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The Unix Hardware Buyer HOWTO

Eric Raymond

              <esr@thyrsus.com>

   Revision History
   Revision 4.2 2010-04-11 Revised by: esr
   DVD region-locking firmware is no longer an issue,
   Revision 4.1 2009-07-01 Revised by: esr
   DTX failed. Finally deprecate SCSI. 32-bit is dead. Avoiding the
   printer-consumables trap. Invasion of the netbooks.
   Revision 4.0 2007-11-02 Revised by: esr
   Major revisions by Jonathan Marsden on SATA, bus standards, DVDs and
   other topics, followed by a cleanup pass from me.
   Revision 3.3 2007-18-13 Revised by: esr
   Updated for 2007 conditions. CRTs are dead. BTX is dead. CD-ROMs are
   competely generic now. USB modems are recommended.
   Revision 3.2 2004-10-28 Revised by: esr
   Fix and remove bad links.
   Revision 3.1 2004-08-03 Revised by: esr
   Sound cards don't matter any more.
   Revision 3.0 2004-02-21 Revised by: esr
   Power-protection stuff moved to UPS HOWTO. DIMM memory is gone. Tape
   drives don't make sense any more. Lots of the theory from my
   "Ultimate Linux Box" articles now lives here.
   Revision 2.4 2003-02-22 Revised by: esr
   URL fixes.
   Revision 2.3 2002-08-06 Revised by: esr
   Buying at the low end isn't a lose anymore. I recommend Athlons.
   Nuked the section on video standards, EDID takes care of all that
   now. Also removed the section on older memory types. And keyboards,
   as the "ergonomic" ones all vanished along with the 1990s
   carpal-tunnel scare.
   Revision 2.2 2002-08-05 Revised by: esr
   New section on DVD drives.
   Revision 2.1 2002-07-08 Revised by: esr
   Corrected Kingston URL. Various small updates for the last year. This
   HOWTO is much more stable than it used to be.
   Revision 2.0 2001-08-09 Revised by: esr
   Major update. Revisions based on Ultimate Linux Box experience.
   Caches are on-chip now. DDS4 tape drives are here. 486 machines, CD
   caddies, and most non-DDS backup technologies are gone.
   Revision 1.1 2001-06-13 Revised by: esr
   Mid-2001 update.
   Revision 1.0 2001-02-06 Revised by: esr
   Initial revision; but see the history in the introduction.

   This is your one-stop resource for information about how to buy and
   configure generic PC hardware for cheap, powerful Unix systems.
     ________________________________________________________________

   Table of Contents
   1. Introduction

        1.1. Purpose of this document
        1.2. New versions of this document
        1.3. Feedback and corrections
        1.4. Related resources

   2. Overview of the Market
   3. Buying the Basics

        3.1. Things to Not Care About
        3.2. How To Pick Your Processor
        3.3. One Disk or Two?
        3.4. Getting Down to Cases
        3.5. Power Supplies and Fans
        3.6. Motherboards
        3.7. Monitor and Video
        3.8. DVD Drives
        3.9. Sound Cards and Speakers
        3.10. Modems
        3.11. Printers
        3.12. Power Protection
        3.13. Radio Frequency Interference

   4. What To Optimize

        4.1. First, add more memory
        4.2. Bus and Disk speeds
        4.3. Optimizing your disk subsystem
        4.4. Tuning Your I/O Subsystem

   5. But What If I'm Economizing?
   6. Noise Control and Heat Dissipation
   7. Special Considerations When Buying Laptops and Netbboks
   8. How to Buy

        8.1. When to Buy
        8.2. Where to Buy
        8.3. Computer Fairs
        8.4. Mail Order
        8.5. Computer Superstores
        8.6. Other Buying Tips

   9. Questions You Should Always Ask Your Vendor

        9.1. Minimum Warranty Provisions
        9.2. Documentation
        9.3. A System Quality Checklist

   10. Things to Check when Buying

        10.1. Tricks and Traps in Warranties
        10.2. Special Questions to Ask Web/Mail-Order Vendors Before
                Buying

        10.3. Payment Method
        10.4. Which Clone Vendors to Talk To

   11. After You Take Delivery
   12. Software to go with your hardware
   13. Other Resources on Building Linux PCs

1. Introduction

1.1. Purpose of this document

   The purpose of this document is to give you the background
   information you need to be a savvy buyer of Intel hardware for
   running Unix. It is aimed especially at hackers and others with the
   technical skills and confidence to go to the Internet/mail-order
   channel, but contains plenty of useful advice for people buying
   store-front retail.

   This document is maintained and periodically updated as a service to
   the net by Eric S. Raymond, who began it for the very best
   self-interested reason that he was in the market and didn't believe
   in plonking down several grand without doing his homework first (no,
   I don't get paid for this, though I have had a bunch of free software
   and hardware dumped on me as a result of it!). Corrections, updates,
   and all pertinent information are welcomed at
   [mailto:esr@snark.thyrsus.com] esr@snark.thyrsus.com. The editorial
   �we' reflects the generous contributions of many savvy Internetters.

   If you email me questions that address gaps in the FAQ material, you
   will probably get a reply that says "Sorry, everything I know about
   this topic is in the HOWTO". If you find out the answer to such a
   question, please share it with me for the HOWTO, so everyone can
   benefit.

   If you end up buying something based on information from this HOWTO,
   please do yourself and the net a favor; make a point of telling the
   vendor "The HOWTO sent me" or some equivalent. If we can show vendors
   that this HOWTO influences a lot of purchasing decisions, we get
   leverage to change some things that need changing.

   Note that in December 1996 I published an introductory article on
   building and tuning Linux systems summarizing much of the material in
   this HOWTO. It's available here. In 2001 I published an article on
   building the Ultimate Linux Box.

   This Buyer's Guide actually dates back to 1992, when it was known as
   the "PC-Clone Unix Hardware Buyer's Guide"; this was before Linux
   took over my world :-). Before that, portions of it were part of a
   Unix Buyer's Guide that I maintained back in the 1980s on USENET.

   It may be a matter of historical interest that the page count of this
   guide peaked in mid-2001 and has been declining since. Video, sound,
   and other functions are migrating onto motherboards. Several bus
   types have disappeared, as have all the old-school backup
   technologies that couldn't scale up to match disk capacities, Spec
   sheets are getting simpler. Accordingly, there are parts that used to
   have whole sections to hemselves that I barely even write about
   anymore -- mice, floppy disks, CD-ROM drives, and keyboards, for
   example, are utterly generic now,

   Another consequence of the technology stabilizing is also that I'm
   updating this guide less often than I used to. Years can now go by
   without the PC market changing in any fundamental way.

   In retrospect, the success of the ATX standard for motherboards in
   1998-1999 was probably the turning point. The PC industry has become
   sufficiently commoditized that your choices are now getting simpler
   rather than more complicated. This is a Good Thing.
     ________________________________________________________________

1.2. New versions of this document

   New versions of the Unix Hardware Buyer HOWTO will be periodically be
   uploaded to various Linux WWW and FTP sites, including the LDP home
   page.

   You can view the latest version of this on the World Wide Web via the
   URL [http://www.tldp.org/HOWTO/Unix-Hardware-Buyer-HOWTO/]
   http://www.tldp.org/HOWTO/Unix-Hardware-Buyer-HOWTO/.
     ________________________________________________________________

1.3. Feedback and corrections

   If you have questions or comments about this document, please feel
   free to mail Eric S. Raymond, at [mailto:esr@thyrsus.com]
   esr@thyrsus.com. I welcome any suggestions or criticisms. If you find
   a mistake with this document, please let me know so I can correct it
   in the next version. Thanks.
     ________________________________________________________________

1.4. Related resources

   You may also want to look at the read the
   [http://www.tldp.org/HOWTO/Hardware-HOWTO.html] Hardware-HOWTO. It
   lists hardware known to be compatible with Linux, and hardware known
   to be incompatible. I've also done a series of articles on The
   Ultimate Linux Box.
     ________________________________________________________________

2. Overview of the Market

   The central fact about PC hardware is that de-facto hardware
   standards have created a commodity market with low entry barriers,
   lots of competitive pressure, and volume high enough to amortize a
   lot of development on the cheap.

   The result is that this hardware gives you lots of bang-per-buck, and
   it's getting both cheaper and better all the time. Furthermore,
   margins are thin enough that vendors have to be lean, hungry, and
   very responsive to the market to survive.

   One good general piece of advice is that you should avoid the
   highest-end new-technology systems (those not yet shipping in
   volume). The problem with the high end is that it usually carries a
   hefty "prestige" price premium, and may be a bit less reliable on
   average because the technology hasn't been through a lot of
   test/improve cycles.

   There used to be a real issue with low-end PCs as well, because there
   used to be a lot of dodgy crap PC components out there going into
   boxes made by vendors trying to save a few cents. That's not really a
   problem anymore. Market pressure has been very effective at raising
   reliability standards for even low-end components as the market has
   matured. It's actually hard to go wrong even buying at the bottom end
   of the market these days.

   I put together the first version of this guide around 1992;
   Unix-capable systems are now ten to twenty times cheaper than they
   were then. At today's prices, building your own system from parts no
   longer makes much sense at all --so this HOWTO is now more oriented
   towards helping you configure a whole system from a single vendor.
     ________________________________________________________________

3. Buying the Basics

   In this section, we cover things to look out for that are more or
   less independent of price-performance tradeoffs, part of your minimum
   system for running Unix.

   Issues like your choice of disk, processor, and I/O bus (where there
   is a significant tradeoff between price and capability) are covered
   in the section on What To Optimize.
     ________________________________________________________________

3.1. Things to Not Care About

   An effect of PC commoditization is that there aren lots of things you
   used to have to worry about that don't matter any more, because the
   market has completely flattened out. We list these here to get them
   out of the way.
     ________________________________________________________________

3.1.1. Bus Wars

   The system bus is what ties all the parts of your machine together.
   This is an area in which progress has simplified your choices a lot.
   There used to be no fewer than four competing bus standards out there
   (ISA, EISA, VESA/VLB, PCI, and PCMCIA). Now there are effectively
   just two --PCI-X on servers, and PCIe for desktop/tower machines.
   Even PCI is now legacy technology, and the PCMCIA bus that seemed so
   important a few years back has been reduced to near-irrelevance by
   Ethernet, USB, and WiFi hardware built onto motherboards. The
   newcomer is PCIe, which is (in late 2007) a `video-card-mostly' bus,
   though it seems to be gaining in popularity for other uses too on
   mainstream desktop motherboards, whereas PCI-X is only found on
   higher end `server' motherboards.
     ________________________________________________________________

3.1.2. Memory

   Judging the memory-controller and cache design used to be one of the
   trickiest parts of evaluating a motherboard, but that stuff is all
   baked into the processor itself now. This removed a large source of
   latency and design variations. It also killed off the plethora of
   different RAM types that used to be out there.

   Today's advice is very simple. Make sure the memory is rated for your
   machine's bus speed, then buy as much as you can afford to stuff in
   your machine.

   Note

   DDR3 RAM is beginning to appear. Right now its extra expense over
   DDR2 is not worth paying, for all but extremely specialized needs. It
   is almost always far more useful to have 4GB of reasonably fast RAM,
   than 2GB of very fast RAM, in your machine.

   For more technical stuff on memory architectures, see The Ultimate
   Memory Guide maintained by Kingston Technologies.
     ________________________________________________________________

3.1.3. Keyboards and Mice

   Keyboards are mostly generic nowadays. One useful piece of advice is
   to not buy any desktop machine with "Internet" buttons on it; this is
   a sure sign of a PC that's an overpriced glitzy toy. Nowadays
   keyboards with a USB connector are the norm, rather than the older
   dedicated connectors; modern open-source Unixes handle these just
   fine.

   Mice and trackballs used to be simple; then, thanks to Microsoft,
   they got complicated. Now they're simple again. Again, USB mice have
   replaced the older PS/2-style dedicated connector. XFree86
   autodetects your mouse when it starts up, so configuration is not a
   big deal any more.

   Some PC vendors, being Windows-oriented, still bundle two-button
   mice. Thus, you may have to buy your own three-button (or two button
   and a scroll wheel) mouse. Ignore the adspeak about dpi and pick a
   mouse or trackball that feels good to your hand.

   Your humble editor really, really likes the Logitech TrackMarble, an
   optical trackball that eliminates the chronic roller-fouling problems
   of the older TrackMan. They're well-supported by X, so any Linux or
   BSD will accept them.
     ________________________________________________________________

3.1.4. Floppy Drives

   There's no longer much to be said about floppy drives. They're cheap,
   they're generic, and the rise of CD-ROM and DVD-ROM drives as a cheap
   distribution medium has made them much less important than formerly.
   You only ever see the 3.5-inch `hard-shell' floppies with 1.44MB
   capacity anymore.

   Bootable CD-ROMs killed off the last use of floppies, which was OS
   installation. So go ahead and settle for cheap Mitsumi and Teac
   floppy drives. There are no `premium' floppy drives anymore. Nobody
   bothers.

   It's possible your system won't even include one. No loss.
     ________________________________________________________________

3.1.5. CD-ROM Drives

   Standard CD-ROMs hold about 650 megabytes of read-only data in a
   format called ISO-9660 (formerly "High Sierra"). All current Unixes
   support these devices. Unix and Linux software is now distributed on
   ISO-9660 CD-ROM, a cheaper and better method than the QIC tapes we
   used to use.

   CD-ROM speed used to be a big deal; vendors advertised 2X, 4X, all
   the way up to 52X. Vendors don't bother any more; the drives are all
   about equivalently fast now.

   There are one or two minor features to watch for. Most CD-ROMS will
   include a headphone jack so you can play audio CDs on them.
   Better-quality ones will also include two RCA jacks for use with
   speakers. Another feature to look for is a drive door or seal that
   protects the drive head from dust.

   Increasingly, DVD-ROM drives (and burners) are replacing CD-ROM
   drives as the default optical drive in PC systems. They have
   significantly larger capacity, and will read (and burn) CD media too.
   The cost difference now is so small that it is usually preferable to
   buy a DVD burner instead of a CD-ROM drive.
     ________________________________________________________________

3.1.6. Backup devices

   It's good to be able to make backups that you can separate from your
   system and store off-site in case of disaster. Until about 2001, tape
   drives still seemed like a good idea for personal systems, but I
   found I seldom used mine. Today, tape drives with high enough
   capacity to image today's huge hard disks are too expensive to make
   sense any more.

   For the money you'd spend on a high-capacity tape drive (over $1000)
   it makes more sense to buy a laptop and a pile of CD-R or DVD-R or
   DVD+R media. Sit the laptop on your house Ethernet when you're not
   traveling, and back up the main machine to it every day, or oftener.
   Between the efficiency of rsync and the speed of 100-megabit
   Ethernet, this will be a lot faster than making a tape. Every once in
   a while, burn a set of backup CD-ROMs or DVDROMs.

   But CD-ROMs aren't reusable; the cost piles up over time. An
   interesting alternative is a small external USB hard drive,
   especially if you can salvage an old laptop drive and put it in a USB
   enclosure. These enclosures are available for about $30; Google for
   "USB HD Enclosure". This is faster than a tape, cheaper and lighter
   than a full laptop. For faster transfer speeds, an enclosure that
   accepts eSATA connections as well as USB helps a lot (assuming your
   PC or notebook has an eSATA connector).
     ________________________________________________________________

3.2. How To Pick Your Processor

   Right now (early 2010), the chips to consider for running Unix are
   the the 64-bit AMD Opteron or its Intel equivalents, especially the
   Core 2 Duo. We're long past the point at which 32-bit chips are
   interesting for new desktop systems, presuming you could even find
   one. AMD and Intel built up a buffer before switching their fabs
   fully to 64-bit chips in 2006, and the 32-bit chips you can still
   find are coming out of warehouses rather than off production lines.

   Brands don't matter much, so don't feel you need to pay Intel's
   premiums if you see an attractive Cyrix, AMD or other chip-clone
   system offered. In the last few years I've been a big fan of the AMD
   line. They used to be faster, cheaper, and better-designed than Intel
   processors; today Intel has clawed back the speed advantage, but AMD
   chips still deliver more performance than you're likely to be able to
   use and do it with lower power dissipation (thus, less noise and
   heat).

   On the other hand, Intel-chip motherboards now have the advantage
   that the on-board graphics chip will give you 3D acceleration with
   fully open-source drivers. This will avoid the problems you would
   otherwise face trying to select a supported graphics card from ATI or
   Nvidia.

   Many CPUs now are multi-core -- that is, they have multiple CPUs on a
   single chip. This is very useful for doing something compute
   intensive (re-encoding video, compressing large archives, etc.) in
   the background and still having a responsive system for other work at
   the same time. At current prices, a dual-core CPU makes good sense
   for most desktop systems. If you are building a server or have
   specialized computing needs you expect to be very CPU-intensive
   quad-core is worth considering, but on a desktop system all the two
   extra cores will usually do is emit heat. Only at the very low end
   (sub US$50 CPUs) do single-core CPUs still make sense on desktop
   machines.

   Mainstream desktop CPUs now use one of two sockets: LGA 775 (Intel)
   and AM2 (AMD). Buying a system that uses one of these stands more
   chance of allowing a useful CPU upgrade to extend its useful life
   than systems using other less common sockets.

   Current CPUs are much faster than those of just a few years ago. As a
   result, unless your needs are highly specialized, spending more than
   about US$200 on a desktop CPU is hard to justify. For most users,
   putting extra budget into more RAM or a faster disk subsystem will
   most likely result in greater benefit.
     ________________________________________________________________

3.3. One Disk or Two?

   I usually build with two disks -- one "system" disk and one "home"
   disk. There are two good reasons to do this that have nothing to do
   with the extra capacity. One of them is the performance advantage of
   being able to interleave commands to different physical spindles that
   we'll explain a bit later in the section on disks. The other is that
   I am quite a bit less likely to lose two disks at once than I am to
   trash a single one.

   Let's suppose you have a fatal disk crash. If you have only one disk,
   goodbye Charlie. If you have two, maybe the crashed one was your
   system disk, in which case you can buy another and mess around with a
   new Linux installation knowing your personal files are safe. Or maybe
   it was your home disk; in that case, you can still run and do
   recovery stuff and basic Net communications until you can buy another
   home disk and restore it from backups (you did keep backups, right?).

   Given today's high capacity drives, another way to use two disks well
   is to set them up as a RAID1 (mirrored) array. This can be done in
   software or with a hardware RAID controller. This way if either of
   the two drives fail, the system will continue to function, no data is
   lost, and upon replacing the failed drive, the array can be rebuilt
   from the remaining working drive. Hard drives are consumable media,
   they do fail, so this approach (as well as good backups) is well
   worth considering.

   Buy SATA. The older IDE and EIDE buses are now obsolete, and SCSI no
   longer has enough of a cost advantage to justify the premium. In
   fact, SCSI has effectively nerged into SCSI; SATA is SCSI commands
   being shipped over a single-wire data line.
     ________________________________________________________________

3.4. Getting Down to Cases

   I used to say that cases are just bent metal, and that it doesn't
   much matter who makes those. Unfortunately, this isn't true any more.
   Processors run so hot these days that fans and airflow are a serious
   concern. They need to be well designed for proper airflow throughout.

   Look for the following quality features:

     * Aluminum rather than steel. It's lighter and conducts heat
       better.
     * Unobstructed air intake with at least one fan each (in addition
       to the power supply and processor fans)
     * No sharp metal edges. You don't want to shred your hands when
       you're tinkering with things.
     * There shouldn't be any hot spots (poor air flow).
     * Sturdy card clips. Some poorly-designed cases allow cards to
       wiggle out of their slots under normal vibration.
     * Effective and easy to use mechanisms for attaching hard drives,
       CD-ROM, CD-R/W, DVDs, etc.

   If you're fussy about RFI (Radio-Frequency Interference), it's worth
   finding out whether the plastic parts of the case have conductive
   coating on the inside; that will cut down emissions significantly,
   but a few cheap cases omit it.

   Should you buy a desktop or tower case? Our advice is go with tower
   unless you're building a no-expansions personal system and expect to
   be using the floppies a lot. Many vendors charge nothing extra for a
   tower case, and the cost difference will be trivial even if they do.
   What you get for that is less desktop clutter, more and bigger bays
   for expansion, and often (perhaps most importantly) a beefed-up
   power-supply and fan. Putting the box and its fan under a table is
   good for maybe 5db off the effective noise level, too. Airflow is
   also an issue; if the peripheral bays are less cramped, you get
   better cooling. Be prepared to buy extension cables for your keyboard
   and monitor, though; vendors almost never include enough flex.

   The airflow thing is a good argument for a full- or mid-tower rather
   than the `baby tower' cases some vendors offer. However, smaller
   towers are getting more attractive as boards and devices shrink and
   more functions migrate onto the motherboard. A state of the art
   system, with all 3" disks, 300W power supply, half-size motherboard,
   on-board SATA and 4GB of RAM sockets, and half-sized expansion cards,
   will fit into a baby or midsized tower with ample room for expansion;
   and the whole thing will fit under a desk and make less noise than a
   classic tower.

   For users with really heavy expandability requirements, rackmount PC
   cases do exist (ask prospective vendors). Typically a rackmount case
   will have pretty much the same functionality as an ordinary PC case.
   But, you can then buy drive racks (complete with power supply), etc.
   to expand into. Also, you can buy passive backplanes with up to 20 or
   so slots. You can either put a CPU card in one of the slots, or
   connect it to an ordinary motherboard through one of the slots.

   Since USB has taken over most forms of detachable peripheral, a good
   feature to look for in a case is USB ports mounted at the top forward
   edge where it's easy to plug in digital cameras and the like.
     ________________________________________________________________

3.5. Power Supplies and Fans

   A lot of people treat power supplies as a commodity, so many
   interchangeable silver bricks. We know better -- cheap power supplies
   go bad, and when they go bad they have a nasty habit of taking out
   the delicate electronics they're feeding. Also, the power supply
   tends to be the noisiest component in your system.

   Give preference to supplies with a Underwriter's Laboratories rating.
   There's some controversy over optimum wattage level. On the one hand,
   you want enough wattage for expansion. On the other, big supplies are
   noisier, and if you draw too little current for the rating the
   delivered voltage can become unstable. And the expected wattage load
   from peripherals is dropping steadily. On the other hand, processors
   and their cooling fans eat a lot more power than they used to.

   The choice is generally between 200W and 300W. After some years of
   deprecating 300W-and-up supplies as overkill, I'm now persuaded it's
   time to go back to them; a modern processor can consume 50-75W by
   itself, and for the newer dual-processor board the power supply needs
   to be rated 450W or up.

   Processors on modern motherboards run hot enough that all vendors
   have gone to embedded temperature sensors and variable-speed
   thermostat-controlled fans, out sheer self-defense (this used to be a
   high-end only feature).

   To cut noise, look for 120mm fans rather than the old-style 80mm
   muffin fans. These can move the same amount of air per minute
   rotating at a lower tip speed, which means less vortex formation and
   less noise. These are now becoming standard even on cheap white-box
   hardware.

   In garden-variety tower cases there often isn't enough airflow to
   cool all components effectively with a single fan, even going at full
   speed. And the single fan in the power supply was basically designed
   to cool the power supply, not the components in the case. This is why
   processors and some graphics cards have their own fans now.

   A few years ago PCs often had two or more case fans in addition to
   the power-supply fan. This made sense in the era of 80mm fans and
   lots of expansion cards obstructing the airflow, but it was noisy.
   Nowadays, with sound and graphics and Ethernet integrated onto
   motherboards, expansion cards are much less common (and processors
   carry their own mini-fans). Thus, today's standard is to mount one
   120mm fan, usually low and forward just beneath the disk-drive stack.
   This is much quieter, like by a factor of three or four.

   The noise produced by a fan is not just a function of the speed with
   which it turns. It also depends on the nature of the airflow produced
   by the fan blades and the bearings of the rotor. If the blades cause
   lots of turbulent airflow, the fan produces lots of noise. One brand
   of fans that is much more silent than most others even if going at
   full throttle is [http://www.papstplc.com/] Papst.
     ________________________________________________________________

3.6. Motherboards

   Provided you exercise a little prudence and stay out of the price
   basement, motherboards and BIOS chips don't vary much in quality.
   There are only six or so major brands of motherboard inside all those
   cases and they're pretty much interchangeable; brand premiums are low
   to nonexistent and cost is strictly tied to maximum speed and bus
   type. There are only four major brands of BIOS chip (AMI, Phoenix,
   Mylex, Award) and not much to choose between 'em but the look of the
   self-test screens (even the "name" vendors use lightly customized
   versions of these). One advantage Unix buyers have is that Unixes are
   built not to rely on the BIOS code (because it can't be used in
   protected mode without more pain than than it's worth). If your BIOS
   will boot properly, you're usually going to be OK.

   Some good features to look for in a motherboard include:

     * Gold-plated contacts in the expansion slots and RAM sockets.
       Base-metal contacts tend to grow an oxidation layer which can
       cause intermittent connection faults that look like bad RAM chips
       or boards. (This is why, if your hardware starts flaking out, one
       of the first things to do is jiggle or remove the boards and
       reseat them, and press down on the RAM chips to reseat them as
       well --this may break up the oxidation layer. If this doesn't
       work, rubbing what contacts you can reach with a soft eraser is a
       good fast way to remove the oxidation film. Beware, some hard
       erasers, including many pencil erasers, can strip off the
       plating, too!)
     * The board should be speed-rated as high as your processor, of
       course. It's good if it's rated higher, so upgrade to a faster
       processor is just a matter of dropping in the chip and a new
       crystal.

   (I used to have "Voltage, temperature and fan speed monitoring
   hardware." on this list. But processors run so hot nowadays that all
   current motherboards have it.)

   The dominant form factor is still ATX. Intel tried to replace it with
   a new standard called BTX in late 2004-2005, but failed; the proposal
   was effectively withdrawn in 2006. In January 2007 AMD announced a
   [http://www.dtxpc.org/] DTX specification for small-form-factor PCs;
   it seems also to have sunk without trace.
     ________________________________________________________________

3.7. Monitor and Video

   The largest user-visible change since the last major update of this
   guide is that the CRT (cathode-ray tube) is dead. The manufacturers
   shut down their production lines in late 2004; the remaining CRTs out
   there are old stock that's been sitting in warehouses. The only
   reason to buy one since then has been to get high-end resolution at a
   price lower than the insanely expensive high-end flatscreens; with
   1920x1440 flatscreens having become generally available at reasonable
   prices even that reason is gone. It's all flatscreens now, baby.

   On flatscreens, only two statistics matter; pixel size and response
   time. The biggest functional drawback of flatscreens relative to CRTs
   is that they refresh more slowly, because cheical reactions in a
   flatscreen pixel take longer than remodulating a flying electron
   beam. You'll never notice this during ordinary desktop use, but it
   can cause streakiness and artifacts when you're playing games or
   viewing movies. If you're going to do that a lot, the price premium
   for a flatscreen with better response time may be worth it.

   Next, buy your card (if you have to; see next paragraph). This used
   to be complicated, with issues like matching the video bandwidths of
   the card and the CRT, and the amount of display memory. Now (unless
   you are a gamer or have similarly extreme 3D acceleration
   requirements) it's simple; all cards have enough display memory for
   every resolution in use, and the issues are software (does it have an
   open-source driver, and do you care?)

   It's actually fairly likely you'll never buy a video card again. Very
   capable graphics chips are routinely integrated onto motherboards
   now; unless you're a gamer or somebody else who absolutely must have
   the latest wheeze in 3D acceleration, they'll be good enough. Even
   this is not a stable situation, as 3D acceleration is commoditizing
   too.

   I used to carry a lot of material on different video standards,
   interlacing, and flicker. That stuff is all obsolete now.

   Here's what to look for on the monitor spec sheet:

     * Screen size and format. Usually measured in diagonal inches. Most
       displays are now in a "widescreen" format (16:10 ratio of
       width:height) rather than the older 5:4 or 4:3 ratios common for
       CRTs and older flat panel screens. A "19 inch" widescreen monitor
       generally has considerably fewer pixels than a "19 inch" 5:4
       ratio one. Unfortunately, this chane is bad for pogrammers, as it
       tends to lose us the vertical pixel resolution we want for editor
       windows.
     * Screen resolution. 1280x1024 is now low end on the desktop.
       Seventeen inch 1280x1024 screens are the bargain basement now,
       many manufacturers have already switched production to 19 inch
       widescreen 1440x900 screens instead. The cost difference between
       such screens and 20 inch 1680x1050 screens is very small, making
       the 20 inch screens a better choice unless funds (or desktop
       space!) are very tight.
     * 5ms or lower response time. 3ms is better. There is some
       marketing-speak going on in the way the response time is
       specified (grey to gray rather than black to white) but since
       most manufacturers do it this way these times are usually
       comparable between different manufacturers screens.
     * Does it have a tilt-and-swivel base? Adequate controls, including
       both horizontal and vertical size and horizontal and vertical
       centering? A color-temperature control is a plus; the last is
       particularly important if you compose graphics on screen for
       hardcopy from a printer.

   If you can, buy your monitor from someplace that will let you see the
   same monitor (the very unit you will walk out the door with, not a
   different or `demo' unit of the same model) that will be on your
   system. There's significant quality variation (even in "premium"
   monitor brands) even among monitors of the same make and model.
     ________________________________________________________________

3.8. DVD Drives

   DVD drives have two main uses in computer systems: playback of video
   DVDs, and use for data storage (either installation media or backups,
   or even as a primary drive in a few specialized systems).

   DVD video playback used to be problematic on Unix due to various
   stupid copy-protection schemes in firmware, but they have long since
   been cracked. These days, any SATA DVD will do fine.

   DVD burners (drives that can read and write CDROM media as well as
   several kinds of DVD media) are now low cost and useful. The SATA
   interface has taken over here, too. Linux and most current PC
   Unix-like systems will work fine with either interface, which is good
   as most PCs now ship with one.
     ________________________________________________________________

3.9. Sound Cards and Speakers

   You can't buy a really bad sound card any more. Even low-end sound
   cards or the sound chips embedded in a lot of PC motherboards these
   days support support all these features:

     * 16-bit sampling (for 65536 dynamic levels rather than 256).
     * Mono and stereo support.
     * Full-duplex mode.
     * Sampling rate of 44.1KHz (CD-quality).
     * MIDI interface via a standard 15-pin D-shell connector.
     * RCA output jacks for headphones or speakers.
     * A microphone jack for sound input.

   If you are interested in multi-track digital recording, two
   particularly good choices are the M-Audio Delta, or RME Hammerfall
   series of cards. Decent (and lower cost!) two-channel cards for more
   normal use are those using the ICE1712 (Envy24) and ICE1724
   (Envy24HT) audio chips. For normal users, though, the on-motherboard
   chips will work fine.

   A rather comprehensive list of sound cards and chips supported by the
   ALSA project, which is the main way sound cards are supported under
   Linux, can be found at ALSA Sound Card Matrix.

   In speakers, look for a magnetically-shielded enclosure with volume,
   bass and treble controls. Some speakers run off the card's 4-watt
   signal; others are "self-powered", using batteries or a separate
   power supply. Your major buying choice is which one of these options
   to pursue. Usually you'll want separately-powered speakers. If
   appropriate for your listening habits, a pair of decent headphones
   will get you better quality sound for the money compared to speakers.

   One final, important tip: that audio cable from your CD-ROM back to
   the sound card is used only when you play audio CD-ROMs through your
   speakers. Software-generated sound goes through the system bus, so
   you can play games with sound even if your sound board or motherboard
   won't accept the audio cable connector.
     ________________________________________________________________

3.10. Modems

   Demand for (dialup telephone) modems is dropping as more and more
   people get broadband Internet through DSL and cable. This section
   still has as much detail as it does only because (a) there are people
   out beyond the exurbs who can't get broadband, and (b) there are one
   or two remaining traps for the unwary.

   The modem market has stabilized and standardized. If you can spend
   $59, get a U.S. Robotics V.92 USB external. You can then know that
   you've got the best and skip the rest of this section. If you really
   must economize, spend $39 for the internal-card version (but you'll
   probably regret the $20 first time you have to do diagnostics).

   Note

   If you live somewhere with really bad telephone lines, the U.S.
   Robotics V.92 Business Modem may be truly "the best" for your needs,
   though it is about four times the price of the U.S. Robotics V.92 USB
   external, which is marketed for home use. See the
   [http://www.usrobotics.com] U.S. Robotics web site for current
   product numbers and more detailed specifications.

   The modem market is like consumer electronics (and unlike the
   computer market as a whole) in that price is a very poor predictor of
   performance. For ordinary file transfers, some $50 modems are better
   than some $150 modems. Paying top dollar mainly buys you better
   tolerance of poor connections and better performance at heavy-duty
   bi-directional transfers (such as you would generate, for exmaple,
   using SLIP or PPP over a leased line to an Internet provider).

   In today's market all modems do a nominal 56kbps --V.90 and V.92 plus
   V.29 or V.17 fax transmission and reception (over plain old phone
   lines you won't get more than 53K of that). You don't see much in the
   way of slow/cheap to fast/expensive product ranges within a single
   brand, because competition is fierce and for many modem board designs
   (those featuring DSP (Digital Signal Processor) chips run by a
   program in ROM) adding a new protocol is basically a software change.
     ________________________________________________________________

3.10.1. Internal vs. External

   Most modems come in two packagings: internal, designed to fit in a PC
   card slot, and external, with its own case, power supply, and
   front-panel lights. Typically you'll pay $20 to $30 more for an
   external modem than you will for the internal equivalent. You'll also
   need a serial or USB port to connect your external modem to.

   Pay that premium -- being able to see the blinkenlights on the
   external ones will help you understand and recover from pathological
   situations. For example, if your Unix system is prone to
   "screaming-tty" syndrome, you'll quickly learn to recognize the
   pattern of flickers that goes with it. Punch the hangup/reset button
   on an external modem and you're done -- whereas with an internal
   modem, you have to go root and flounder around killing processes and
   maybe cold-boot the machine just to reset the card.

   See Rick's Rants for extended discussion of this point.
     ________________________________________________________________

3.10.2. Pitfalls to Avoid

   Don't buy a serial (RS232C) modem. This used to be the only kind
   there was, but they were always a bitch to configure and
   troubleshoot. Go USB instead; the sanity you save may be your own.

   If the abbreviation "RPI" occurs anywhere on the box, don't even
   consider buying the modem. RPI (Rockwell Protocol Interface) is a
   proprietary "standard" that allows modem makers to save a few bucks
   at your expense by using a cheap-jack Rockwell chipset that doesn't
   do error correction. Instead, it hands the job off to a modem driver
   which (on a Unix machine) you will not have.

   Also avoid anything called a "Windows Modem" or "WinModem", "HCF", or
   "HSP"; these lobotomized pieces of crap require a Windows DLL to run.
   They will eat up to 25% of your processor clocks during transfers,
   and hog high-priority interrupts (causing your machine to stall under
   Windows even if your processor still has spare cycles).

   A good way to avoid falling into the WinModem trap is to look for the
   designation "OEM modem". This is apparently the new industry-speak
   for a modem with an on-board harware DSP. Occasionally you'll see
   these called "gaming modems".
     ________________________________________________________________

3.10.3. Fax Modems

   Many modems come with bundled Windows fax software that is at best
   useless under Unix, and at worst a software kluge to cover inadequate
   hardware. Avoid these bundles and buy a bare modem -- it's cheaper,
   and lowers the likelihood that something vital to your communications
   needs has been left out of the hardware.

   Avoid "Class 1" and "Class 2" modems. Look for "Class 2.0" for the
   full EIA-standard command set.

   Fax capability is included with effectively all modems these days;
   it's cheap for manufacturers, being basically a pure software add-on.
   The CCITT also sets fax protocol standards. Terms to know:

   V.29
          CCITT standard for Group III fax encoding at 9600bps

   V.17
          CCITT standard for Group III fax encoding at 14400bps

   There's a separate series of standards for software control of fax
   modems over the serial (or USB) line maintained by the Electronics
   Industry Association and friends. These are:

   Class 1 -- base EIA standard for fax control as extensions to the
   Hayes AT command set.

   Class 2.0 -- enhanced EIA standard including compression, error
   correction, station ID and other features.

   Class 2 -- marketroidian for anything between Class 1 and Class 2.0.
   Different "Class 2" modems implement different draft subsets of the
   2.0 standard, so "Class 2" fax software won't necessarily drive any
   given "Class 2" modem.

   There's also a proprietary Intel "standard" called CAS, Communicating
   Applications Specification. Ignore it; only Intel products support
   it.
     ________________________________________________________________

3.11. Printers

   The most important thing to optimize nowadays is cost of consumables.
   Printer manufacturers, especially at the low end, have adopted a
   model under which they sell printers with near-zero or even negative
   margin, then gouge you horribly on the cost of cartridges and ink.
   Common tactics include (a) shipping half-filled "starter" cartridges
   with your printer, so you have to replace much sooner than you'd
   think, (b) toner-empty sensors deliberately miscalibrated to blink
   the error light on your printer when they're still a quarter to a
   third full, and (c) electronic countermeasures to lock out cheap
   third-party refills - in one notorious case, a printer manufacturer
   used the DMCA to sue refill vebdoers who circumvented these!

   Better dealers (the Staples chain, for example) will show you a chart
   covering price and consumable-cost-per-page for all the models they
   carry. If you don't see this, leave. When you do, estimate your
   monthly print volume and trade off up-front against consumables
   price. appropriately. Hint: The vendors count on you underestimating
   your volume and consumables cost, and you usually will. Payiing a few
   extra bucks up front to lower that cost is smart.

   Other than that, there really isn't all that much to be said about
   printers; the market is thoroughly commoditized and printer
   capabilities pretty much independent of the rest of your hardware.
   The PC-clone magazines will tell you what you need to know about
   print quality, speed, features, etc. The business users they feed on
   are obsessed with all these things.

   (There used to be a problem with "GDI printers" and "WinPrinters"
   that only worked with Windows --they required special drivers that
   took over your CPU to do image processing, These were such a bad idea
   that they have basically disappeared off the market.)

   Most popular printers are supported by GhostScript, and so it's easy
   to make them do PostScript. If you're buying any letter-quality
   printer (laser or ink-jet), check to see if it's on GhostScript's
   supported device list -- otherwise you'll have to pay a premium for
   Postscript capability! Postscript is still high-end in the Windows
   market, but it's ubiquitous in the Unix world.

   Warning, however: if you're using ghostscript on a non-Postscript
   printer, printspeed will be slow, especially with a serial printer. A
   bitmapped 600 dpi page has a lot of pixels on it. At today's prices,
   paying the small premium for Postscript capability makes sense.

   If you're buying a printer for home, an inkjet is a good choice
   because it doesn't use gobs of power and you won't have the
   toner/ozone/noise/etc mess that you do with a laser. If all you want
   is plain-ASCII, dot-matrix is cheaper to buy and run -- if you can
   find one. Inexpensive ink-jets and lasers have almost driven them off
   the market.

   Inkjets are great in that they're cheap, many of them do color, and
   there are many kinds which aren't PCL but are understood by
   Ghostscript anyway. If you print very infrequently (less than weekly,
   say), you should be careful to buy a printer whose print head gets
   replaced with every ink cartrige: infrequent use can lead to the
   drying of the ink, both in the ink cartrige and in the print head.
   The print heads you don't replace with the cartrige tend to cost
   nearly as much as the printer (~$200 for an Epson Stylus 800) once
   the warranty runs out (the third such repair, just after the warranty
   expired, totalled one informant's Stylus 800). Be careful, check
   print head replacement costs ahead of time, and run at least a
   cleaning cycle if you don't actually print anything in a given week.
   (Conversely, toner starts out dry, and ribbon ink won't evaporate for
   years...if you truly print only rarely, but neither a dot matrix nor
   a laser makes sense, consider buying no printer and taking your
   PostScript files to a copy shop...)

   Nowadays, a lot of printers are moving away from parallel-port
   interfaces to USB. This is a good idea, because USB devices announce
   themselves to the host computer and can be automatically configured.
   Parallel ports (and serial ports for that matter) are becoming
   obsolete. Many new PC motherboards no longer include them.

   Many printers (even some sub-$100 models) now come with a network
   (10/100 Ethernet) interface. This make sharing them trivial, and also
   avoids having to leave a desktop PC powered on so others (using
   notebooks perhaps) can print to your printer. Therefore, such
   printers are worth considering in many networked environments,
   including home networks.

   In the near future, new motherboards may stop including parallel and
   serial ports altogether. That's another good reason to go with a USB-
   or Ethernet-capable printer.
     ________________________________________________________________

3.12. Power Protection

   I strongly recommend that you buy a UPS to protect your hardware and
   data. MOV-filtered power bars make nice fuses (they're cheap to
   replace), but they're not enough. I have written a UPS HOWTO that
   provides more complete coverage of what used to be in this section.
     ________________________________________________________________

3.13. Radio Frequency Interference

   (Thanks to Robert Corbett <Robert.Corbett@Eng.Sun.COM> for
   contributing much of this section)

   Radio Frequency Interference (RFI) is a growing problem with PC-class
   machines. Today's processor speeds are such that the electromagnetic
   noise generated by a PC's circuitry in normal operation can degrade
   or jam radio and TV reception in the neighborhood. Such noise is
   called Radio Frequency Interference (RFI). Computers, as transmitting
   devices, are regulated by the Federal Communications Commission
   (FCC).

   FCC regulations recognize two classes of computer:

   If a PC is to be used in a home or apartment, it must be certified to
   be FCC class B. If it is not, neighbors have a legal right to prevent
   its use. FCC class A equipment is allowed in industrial environments.

   Many systems are not FCC class B. Some manufacturers build boxes that
   are class B and then ship them with class A monitors or external disk
   drives. Even the cables can be a source of RFI.

   It pays to be cautious. For example, the Mag MX17F is FCC class B.
   There are less expensive versions of the MX17 that are not. The Mag
   MX17 is a great monitor. It would be painful to own one and not be
   allowed to use it.

   An upgradeable system poses special problems. A system that is FCC
   class B with a 33 MHz CPU might not be when the CPU is upgraded to a
   50 or 66 MHz CPU. Some upgrades require knockouts in the case to be
   removed. If a knockout is larger than whatever replaces it, RFI can
   leak out through the gap. Grounded metal shims can eliminate the
   leaks.

   Even Class B systems don't mix well with wireless phonesets (not
   cellular phones, but the kind with a base station and antennaed
   headset). You'll often find a wireless phone hard to use withing 20
   feet of a Class B machine.

   To cut down on RFI, get a good metal case with tight joints, or at
   least make sure any plastic one you buy has a conductive lining. You
   can also strip the painted metal-to-metal contacting parts of paint
   so that there's good conductive metal contact. Paint's a poor
   conductor in most cases, so you can get some benefit from this.
     ________________________________________________________________

4. What To Optimize

4.1. First, add more memory

   Max out your memory. Having lots of free memory will improve your
   virtual-memory performance (and Unix takes advantage of extra memory
   more effectively than Windows does). Fortunately, with RAM as cheap
   as it is now, a gigabyte or three is unlikely to bust your budget
   even if you're economizing.
     ________________________________________________________________

4.2. Bus and Disk speeds

   Most people think of the processor as the most important choice in
   specifying any kind of personal-computer system. But for typical job
   loads under Linux, the processor type is nearly a red herring -- it's
   far more important to specify a capable system bus and disk I/O
   subsystem. If you don't believe this, you may find it enlightening to
   keep top(1) running for a while as you use your machine. Notice how
   seldom the CPU idle percentage drops below 90%!

   It's true that after people upgrade their motherboards they often do
   report a throughput increase. But this is often more due to other
   changes that go with the processor upgrade, such as improved cache
   memory or an increase in the clocking speed of the system's
   front-side bus (enabling data to get in and out of the processor
   faster).

   If you're buying for Linux on a fixed budget, it makes sense to trade
   away some excess processor clocks to get a faster bus and disk
   subsystem. If you're building a monster hot-rod, go ahead and buy
   that fastest available processor -- but once you've gotten past that
   gearhead desire for big numbers, pay careful attention to bus speeds
   and your disk subsystem, because that's where you'll get the serious
   performance wins. The gap between processor speed and I/O subsystem
   throughput has only widened in the last five years.

   How does it translate into a recipe in 2010? Like this; if you're
   building a hot rod,

     * Do buy a machine with the fastest available "front-side" (e.g.
       processor-to-memory) bus.
     * Do get the fastest SATA disks you can get your hands on.
     ________________________________________________________________

4.3. Optimizing your disk subsystem

   For the fastest disks you can find, pay close attention to average
   seek and latency time. The former is an average time required to seek
   to any track; the latter is the maximum time required for any sector
   on a track to come under the heads, and is a function of the disk's
   rotation speed.

   Of these, average seek time is much more important. When you're
   running Linux or any other virtual-memory operating system, a one
   millisecond faster seek time can make a really substantial difference
   in system throughput. Back when PC processors were slow enough for
   the comparison to be possible (and I was running System V Unix), it
   was easily worth as much as a 30MHz increment in processor speed.
   Today the corresponding figure would probably be as much as 300MHz!

   The manufacturers themselves avoid running up seek time on the
   larger-capacity drives by stacking platters vertically rather than
   increasing the platter size. Thus, seek time (which is proportional
   to the platter radius and head-motion speed) tends to be constant
   across different capacities in the same product line. This is good
   because it means you don't have to worry about a capacity-vs.-speed
   tradeoff.

   Average drive latency is inversely proportional to the disk's
   rotational speed. For years, most disks spun at 3600 rpm; most disks
   now spin at 7,200 or 10,000rpm, and high-end disks at 15,000 rpm.
   These fast-spin disks run extremely hot; cooling is becoming a
   critical constraint in drive design.

   For years, your basic decision was SATA vs. SCSI (the older IDE and
   EIDE buses are long obsolete). Not in 2009; SATA 3 devices and
   controllers are good enough that the performance advantage of SCSI is
   marginal unless you are designing a super-high-end server box -
   slightly faster transfer speeds (320MB/s vs. 300MB/s) and slightly
   better susrained throughput.

   The SCSI price premium entailed in an extra controller and more
   expensive disks are no longer worth it for the home builder, even
   from the point of view of grizzled old SCSI partisans like me.
   Accordingly, I've dropped most of the detailed SCSI information I
   used to carry here.

   Final note: Solid-state drives loom on the horizon as replacements
   for SATA disks, but the price per megabyte is still high enough that
   as yet they're only being deployed in small capacities on netbooks.
   Watch this space.
     ________________________________________________________________

4.4. Tuning Your I/O Subsystem

   (This section comes to us courtesy of Perry The Cynic,
   <perry@sutr.cynic.org>; it was written in 1998. My own experience
   agrees pretty completely with his. I have revised the numbers in it
   since to reflect more recent developments.)

   Building a good I/O subsystem boils down to two major points: pick
   matched components so you don't over-build any piece without benefit,
   and construct the whole pipe such that it can feed what your
   OS/application combo needs.

   It's important to recognize that "balance" is with respect to not
   only a particular processor/memory subsystem, but also to a
   particular OS and application mix. A Unix server machine running the
   whole TCP/IP server suite has radically different I/O requirements
   than a video-editing workstation. For the "big boys" a good
   consultant will sample the I/O mix (by reading existing system
   performance logs or taking new measurements) and figure out how big
   the I/O system needs to be to satisfy that app mix. This is not
   something your typical Linux buyer will want to do; for one, the
   application mix is not static and will change over time. So what
   you'll do instead is design an I/O subsystem that is internally
   matched and provides maximum potential I/O performance for the money
   you're willing to spend. Then you look at the price points and
   compare them with those for the memory subsystem. That's the most
   important trade-off inside the box.

   So the job now is to design and buy an I/O subsystem that is well
   matched to provide the best bang for your buck. The two major
   performance numbers for disk I/O are latency and bandwidth. Latency
   is how long a program has to wait to get a little piece of random
   data it asked for. Bandwidth is how much contiguous data can be sent
   to/from the disk once you've done the first piece. Latency is
   measured in milliseconds (ms); bandwidth in megabytes per second
   (MB/s). Obviously, a third number of interest is how big all of your
   disks are together (how much storage you've got), in Gigabytes (GB).

   Within a rather big envelope, minimizing latency is the cat's meow.
   Every millisecond you shave off effective latency will make your
   system feel significantly faster. Bandwidth, on the other hand, only
   helps you if you suck a big chunk of contiguous data off the disk,
   which happens rarely to most programs. You have to keep bandwidth in
   mind to avoid mis-matching pieces, because (obviously) the lowest
   usable bandwidth in a pipe constrains everything else.

   I'm going to ignore IDE. IDE is no good for multi-processing systems,
   period. You may use an IDE CD-ROM if you don't care about its
   performance, but if you care about your I/O performance, go SCSI.
   (Beware that if you mix an IDE CD-ROM with SCSI drives under Linux,
   you'll have to run a SCSI emulation layer that is a bit flaky.)

   Let's look at the disks first. Whenever you seriously look at a disk,
   get its data sheet. Every reputable manufacturer has them on their
   website; just read off the product code and follow the bouncing
   lights. Beware of numbers (`<12ms fast!') you may see in ads; these
   folks often look for the lowest/highest numbers on the data sheet and
   stick them into the ad copy. Not dishonest (usually), but ignorant.

   What you need to find out for a disk is:

    1. What kind of SCSI interface does it have? Look for "fast",
       "ultra", and "wide". Ignore disks that say "fiber" (this is a
       specialty physical layer not appropriate for the insides of small
       computers). Note that you'll often find the same disk with
       different interfaces.
    2. What is the "typical seek" time (ms)? Make sure you get
       "typical", not "track-to-track" or "maximum" or some other
       measure (these don't relate in obvious ways, due to things like
       head-settling time).
    3. What is the rotational speed? This is typically 4500, 5400, 7200,
       10000, or 15000 rpm (rotations per minute). Also look for
       "rotational latency" (in ms). (In a pinch, average rotational
       latency is approx. 30000/rpm in milliseconds.)
    4. What is the `media transfer rate' or speed (in MB/s)? Many disks
       will have a range of numbers (say, 7.2-10.8MB/s). Don't confuse
       this with the "interface transfer rate" which is always a round
       number (10 or 20 or 40MB/s) and is the speed of the SCSI bus
       itself.

   These numbers will let you do apple-with-apples comparisons of disks.
   Beware that they will differ on different-size models of the same
   disk; typically, bigger disks have slower seek times.

   Now what does it all mean? Bandwidth first: the `media transfer rate'
   is how much data you can, under ideal conditions, get off the disk
   per second. This is a function mostly of rotation speed; the faster
   the disk rotates, the more data passes under the heads per time unit.
   This constrains the sustained bandwidth of this disk.

   More interestingly, your effective latency is the sum of typical seek
   time and rotational latency. So for a disk with 8.5ms seek time and
   4ms rotational latency, you can expect to spend about 12.5ms between
   the moment the disk `wants' to read your data and the moment when it
   actually starts reading it. This is the one number you are trying to
   make small. Thus, you're looking for a disk with low seek times and
   high rotation (RPM) rates.

   For comparison purposes, the first hard drive I ever bought was a
   20MB drive with 65ms seek time and about 3000RPM rotation. A floppy
   drive has about 100-200ms seek time. A CD-ROM drive can be anywhere
   between 120ms (fast) and 400ms (slow). The best IDE harddrives have
   about 10-12ms and 5400 rpm. The best SCSI harddrive I know (the
   Fujitsu MAM) runs 3.9ms/15000rpm.

   Fast, big drives are expensive. Really big drives are very expensive.
   Really fast drives are pretty expensive. On the other end, really
   slow, small drives are cheap but not cost effective, because it
   doesn't cost any less to make the cases, ship the drives, and sell
   them.

   In between is a `sweet spot' where moving in either direction
   (cheaper or more expensive) will cost you more than you get out of
   it. The sweet spot moves (towards better value) with time. If you can
   make the effort, go to your local computer superstore and write down
   a dozen or so drives they sell `naked'. (If they don't sell at least
   a dozen hard drives naked, find yourself a better store. Use the Web,
   Luke!) Plot cost against size, seek and rotational speed, and it will
   usually become pretty obvious which ones to get for your budget.

   Do look for specials in stores; many superstores buy overstock from
   manufacturers. If this is near the sweet spot, it's often
   surprisingly cheaper than comparable drives. Just make sure you
   understand the warranty procedures.

   Note that if you need a lot of capacity, you may be better off with
   two (or more) drives than a single, bigger one. Not only can it be
   cheaper but you end up with two separate head assemblies that move
   independently, which can cut down on latency quite a bit (see below).

   If you find yourself at the high end of the bandwidth game, be aware
   that the theoretical maximum of the PCI bus itself is 132MB/s. That
   means that a dual ultra/wide SCSI controller (2x40MB/s) can fill more
   than half of the PCI bus's bandwidth, and it is not advised to add
   another fast controller to that mix. As it is, your device driver
   better be well written, or your entire system will melt down
   (figuratively speaking).

   Incidentally, all of the numbers I used are `optimal' bandwidth
   numbers. The real scoop is usually somewhere between 50-70% of
   nominal, but things tend to cancel out -- the drives don't quite
   transfer as fast as they might, but the SCSI bus has overhead too, as
   does the controller card.

   Whether you have a single disk or multiple ones, on one or several
   SCSI buses, you should give careful thought to their partition
   layout. Given a set of disks and controllers, this is the most
   crucial performance decision you'll make.

   A partition is a contiguous group of sectors on the disk.
   Partitioning typically starts at the outside and proceeds inwards.
   All partitions on one disk share a single head assembly. That means
   that if you try to overlap I/O on the first and last partition of a
   disk, the heads must move full stroke back and forth over the disk,
   which can radically increase seek time delays. A partition that is in
   the middle of a partition stack is likely to have best seek
   performance, since at worst the heads only have to move half-way to
   get there (and they're likely to be around the area anyway).

   Whenever possible, split partitions that compete onto different
   disks. For example, /usr and the swap should be on different disks if
   at all possible (unless you have outrageous amounts of RAM).

   Another wrinkle is that most modern disks use `zone sectoring'. The
   upshot is that outside partitions will have higher bandwidth than
   inner ones (there is more data under the heads per revolution). So if
   you need a work area for data streaming (say, a CD-R pre-image to
   record), it should go on an outside (early numbered) partition of a
   fast-rotating disk. Conversely, it's a good convention to put
   rarely-used, performance-uncritical partitions on the inside (last).

   Ah yes, caches. There are three major points where you could cache
   I/O buffers: the OS, the controller card or chip in your machine, and
   the on-disk controller. Intelligent OS caching is by far the biggest
   win, for many reasons. RAM caches on controller cards are pretty
   pointless these days; you shouldn't pay extra for them, and
   experiment with disabling them if you're into tinkering.

   RAM caches on the drives themselves are a mixed bag. At moderate size
   (1-2MB), they are a potential big win for Windows 95/98, because
   Windows has stupid VM and I/O drivers. If you run a true
   multi-tasking OS like Linux, having unified RAM caches on the disk is
   a significant loss, since the overlapping I/O threads kick each other
   out of the cache, and the disk ends up performing work for nothing.

   Most high-performance disks can be reconfigured (using mode page
   parameters, see above) to have `segmented' caches (sort of like a
   set-associative memory cache). With that configured properly, the RAM
   caches can be a moderate win, not because caching is so great on the
   disk (it's much better in the OS), but because it allows the disk
   controller more flexibility to reschedule its I/O request queue. You
   won't really notice it unless you routinely have >2 I/O requests
   pending at the SCSI level. The conventional wisdom (try it both ways)
   applies.

   And finally I do have to make a disclaimer. Much of the stuff above
   is shameless simplification. In reality, high-performance disks are
   very complicated beasties. They run little mini-operating systems
   that are most comfortable if they have 10-20 I/O requests pending at
   the same time. Under those circumstances, the amortized global
   latencies are much reduced, though any single request may experience
   longer latencies than if it were the only one pending. The only
   really valid analysis are stochastic-process models, which we really
   don't want to get into here. :-)
     ________________________________________________________________

5. But What If I'm Economizing?

   If you are economizing, here's a simple rule:

     * Do buy a CPU/motherboard one or two levels lower than commercial
       state of the art.

   For best value, look in the middle of the current range of available
   processors. On the desktop, in late 2007, that means a CPU costing
   perhaps $75 to $200, not the latest and greatest quad core marvels
   selling for several times that!

   Why? Because of the way manufacturers' price-performance curves are
   shaped. The top-of-line system is generally boob bait for corporate
   executives and other people with more money than sense. Chances are
   the system design is new and untried -- if you're at the wrong point
   in the technology cycle, the chip may even be a pre-production
   sample, or an early production stepping with undiscovered bugs like
   the infamous FDIV problem in early Pentiums. You don't need such
   troubles. Better to go with a chip/motherboard combination that's
   been out for a while and is known good. It's not like you really need
   the extra speed, after all.

   Besides, if you buy one of these gold-plated systems, you're only
   going to kick yourself three months later when the price plunges by
   30%. Further down the product line there's been more real competition
   and the manufacturer's margins are already squeezed. There's less
   room for prices to fall, so you won't watch your new toy lose street
   value so fast. Its price will still drop, but it won't plummet
   sickeningly.

   Again, bear in mind that the cheapest processor you can buy new today
   is plenty fast enough for Linux. So if dropping back a speed level or
   two brings you in under budget, you can do it with no regrets.

   Consider one drive rather than two. This will reduce overall system
   performance somewhat, but the cost saving as a fraction of total
   system cost is often substantial.

   Another easy economy measure is looking for repaired or reconditioned
   parts with a warranty. These are often as good as new, and much
   cheaper.

   Your display is one of the areas where pinching pennies is not a good
   idea. You're going to be looking at that display for hours on end.
   You are going to be using the screen real estate constantly. Buy the
   best quality, largest screen you possibly can -- it will be worth it.

   Similarly, do not reduce the amount of RAM in your system too far. A
   minimum of 4GB of RAM is helpful in desktop systems today.
     ________________________________________________________________

6. Noise Control and Heat Dissipation

   An increasingly critical aspect of machine design is handling the
   waste heat and acoustic noise of operation. This may seem like a
   boring subject, but cooling is a centrally important one if you want
   your machine to last -- because thermal stress from the electronics'
   own waste heat is almost certainly what will kill it. You want that
   fatal moment to happen later rather than sooner. On the other hand,
   cooling makes acoustic noise, which human beings don't tolerate well.

   This tradeoff bites harder than you think; it's the fundamental
   reason that, despite my money-is-no-object premise in the Ultimate
   Linux Box artcles, I didn't go to relatively exotic technologies like
   liquid-cooled overclocking or RAID disk arrays for a performance
   boost. Sure, they may initially look attractive -- but overclocked
   chips and banks of disk drives require massive cooling with lots of
   moving parts, and it's not good to be trying to do creative work like
   programming with anything that sounds quite so much like an idling
   jet engine sitting beside one's desk.

   In 2001 we had already reached the point at which the thermal load
   vs. cooling-noise tradeoff is the effective limiting factor in the
   performance of personal machines. Ten years ago, even low-end and
   medium "server" machines differed from personal-PC designs in fairly
   important ways (different processor and bus types, different speed
   ranges, etc.) Nowadays specialized server architectures are in
   retreat at the high end of the market and everything else looks like
   a PC. And the difference between a "PC" and a "server" is mainly that
   servers live in server rooms, and are allowed to have monster cases
   with lots of noisy fans.

   So how do we manage this tradeoff for a personal, desktop or
   desk-side machine? Careful choice of components and being willing to
   pay some price premium for cool-running and low-noise characteristics
   can help a lot. Even exceptionally clueful system integrators can't
   generally afford to do this, because they're under constant
   competitive pressure to cut price and costs by using generic
   components.

   Reducing expected noise and heat in a design call for different
   strategies. It's relatively easy to find decibel figures for the
   noisemaking parts in a PC design. And, once you know a little basic
   audiometry and a few basic rules of thumb, it's not hard to form a
   fair estimate of your design's noisiness. Estimating a design's heat
   dissipation is harder, partly because the waste-heat emission of a
   PC's subsystems tends to vary in a more complex way than the acoustic
   emissions of the mechanical parts. This means that you can and should
   try to design ahead for low noise, but on the other hand expect to
   have to monitor for heat-dissipation problems in your prototype and
   solve them by building in more cooling.

   Here's the basic audiometry you need to know to control your design's
   noise emissions:

   Sound is measured in decibels, abbreviated dB, relative to the
   threshold of audibility, "A". (Thus, sound levels above that
   threshold are written "dBA".) The scale is logarithmic, with every
   3dB increment roughly doubling sound intensity.

   For sounds that are not phase-related, decibel levels add as a
   logarithmic sum. Thus if X and Y are uncorrelated sound sources,

   dBA(X + Y) = 10 * log(10 ^ (dBA(X)/10) + 10 ^ (dBA(Y)/10))

   A consequence of the above formula is that dBA(X + Y) cannot be more
   than 3dB above the greater of dBA(X) and dBA(Y) for uncorrelated
   sources (6dB for perfectly correlated ones).

   Sound from a point source decays by an inverse-square law, roughly
   6dB for each doubling of distance.

   Important thresholds on the decibel scale:

   0 dBA
          Threshold of hearing

   20 dBA
          Rustling leaves, quiet living room

   30 dBA
          Quiet office

   40 dBA
          Quiet conversation

   45 dBA
          Threshold of distraction, according to EPA

   50 dBA
          Quiet street, average office noise

   60 dBA
          Normal conversation (1 foot distance)

   70 dBA
          Inside car

   75 dBA
          Loud singing (3 feet)

   80 dBA
          Typical home-stereo listening level

   The acoustic noise emitted by PCs is normally a combination of white
   noise produced by airflow, high-frequency noise produced by bearing
   friction in drive spindles and fans, and the constant frequency
   "blade passing" noise that all propellers emit (the latter is often
   more intense than white noise and bearing whine).

   The best low-noise ball-bearing case fans emit around 20dBA. Typical
   sleeve-bearing fans emit 30-50dBA.

   According to the indispensable [http://tomshardware.com/] Tom's
   Hardware site, you can expect to cut at least 5dB off the interior
   noise level of the computer with a good choice of case. We'll improve
   on that by adding sound-absorbing material to the interior.
     ________________________________________________________________

7. Special Considerations When Buying Laptops and Netbboks

   First, don't be misled by the term "netbook". A netbook is just a
   small, low-priced, low-power laptop with relatively small solid-state
   drives. Because the display and drive capacity are small, netbooks
   are basically just good for email and surfing. If you're going to do
   coding or even much word processing you'll need something more like a
   traditional laptop or desktop.

   Up until about 1999 the laptop market was completely crazy. The
   technology was in a state of violent flux, with "standards" phasing
   in and out and prices dropping like rocks. Things are beginning to
   settle out a bit more now.

   One sign of this change is that there are now a couple of laptop
   lines that are clear best-of-breeds for reasons having as much to do
   with good industrial design and ergonomics as the technical details
   of the processor and display.

   In lightweight machines, I was a big fan of the Sony VAIO line. I
   owned one from early 1999 until it physically disintegrated under the
   rigors of travel in late 2000, and could hardly imagine switching.
   They weigh 3.5 pounds, give you an honest 3 hours of life per
   detachable battery pack, have a very nice 1024x768 display, and are
   just plain pretty. Their only serious drawback is that they're not
   rugged, and often fall apart after a year or so of use.

   If you want a full-power laptop that can compete with or replace your
   desktop machine, the Lenovo (formerly IBM) ThinkPad line is the bomb.
   Capable, rugged, and nicely designed. I now use a ThinkPad X61, the
   lightest and smallest machine in the line, and like it a lot.

   These machines are not cheap, though. If you're trying to save money
   by buying a no-name laptop, here are things to look for:

   First: despite what you may believe, the most important aspect of any
   laptop is not the CPU, or the disk, or the memory, or the screen, or
   the battery capacity. It's the keyboard feel, since unlike in a PC,
   you cannot throw the keyboard away and replace it with another one
   unless you replace the whole computer. Never buy any laptop that you
   have not typed on for a couple hours. Trying a keyboard for a few
   minutes is not enough. Keyboards have very subtle properties that can
   still affect whether they mess up your wrists.

   A standard desktop keyboard has keycaps 19mm across with 7.55mm
   between them. If you plot frequency of typing errors against keycap
   size, it turns out there's a sharp knee in the curve at 17.8
   millimeters. Beware of "kneetop" and "palmtop" machines, which
   squeeze the keycaps a lot tighter and typically don't have enough
   oomph for Unix anyway; you're best off with the "notebook" class
   machines that have full-sized keys.

   Second: with present flatscreens, 1920x1200 color is the best you're
   going to do (and that is on a 17in widescreen, which translates to a
   large notebook. On normal size notebooks, a maximum of 1440x900 is
   more common). On travel machines like the Lenovo X serties, you're
   still stuck with 1024x768. If you want more than that (for X, for
   example) you have to either fall back to a desktop or make sure
   there's an external-monitor port on the laptop (and many laptops
   won't support higher resolution than the flatscreen's).

   Third: about those vendor-supplied time-between-recharge figures;
   don't believe them. They collect those from a totally quiescent
   machine, sometimes with the screen or hard disk turned off. Under
   Windows, you'd be lucky to get half the endurance they quote; under
   Unix, which hits the disk more often, it may be less yet. Figures
   from magazine reviews are more reliable.

   Fourth: You can now avoid many of the driver hassles involved in
   getting some devices on your notebook to work (or week well) under
   Linux by purchasing a notebook with Linux pre-installed. Dell has
   recently started to make noise in this regard in the Linux community.
   Taking this approach limits the set of notebooks you can consider,
   but the one you get is likely to "just work" (including sound, useful
   capabilities like suspend/resume, and even hotplugging of external
   displays and projectors) to a much higher degree under Linux than
   others.
     ________________________________________________________________

8. How to Buy

8.1. When to Buy

   It used to be that good configurations for Unix were what the market
   called `server' machines, with beefed-up I/O subsystems and fast
   buses. No longer; today's `servers' are monster boxes with multiple
   power supplies and processors, gigabytes of memory, and
   industrial-grade air cooling --they're not really suitable as
   personal machines. A typical SCSI desktop workstation is as much as
   you'll need.

   Prices keep dropping, so there's a temptation to wait forever to buy.
   A good way to cope with this is to configure your system on paper,
   get a couple of initial estimates, then set a trigger price, below
   the lowest one, at what you're willing to pay. Then watch and wait.
   When the configuration cost hits your trigger price, place your
   order.

   The advantage of this method is that it requires you to settle in
   your mind, well in advance, what you're willing to pay for what
   you're getting. That way, you'll buy at the earliest time you should,
   and won't stress too much out afterwards as it depreciates.

   Before you shop, do your homework. Publications like "Computer
   Shopper" (and their web site at [http://www.computershopper.com]
   http://www.computershopper.com) are invaluable for helping you get a
   feel for prices and what clonemakers are doing. Another excellent
   site is [http://www.computeresp.com] ComputerESP.
     ________________________________________________________________

8.2. Where to Buy

   The most important where-to-buy advice is negative. Do not go to a
   traditional, business-oriented storefront dealership. Their overheads
   are high. So are their prices.

   Especially, run --do not walk --away from any outfit that trumpets
   `business solutions'. This is marketing code for the kind of place
   that will justify a heavy price premium by promising after-sale
   service and training which, nine times out of ten, will turn out to
   be nonexistent or incompetent. Sure, they'll give you plush carpeting
   and a firm handshake from a guy with too many teeth and an expensive
   watch --but did you really want to pay for that?

   There are two major alternatives to storefront dealerships and one
   minor one. The major ones are mail order and computer superstores.
   The minor one is computer fairs.
     ________________________________________________________________

8.3. Computer Fairs

   I used to be a big fan of hole-in-the-wall stores run by immigrants
   from the other side of the International Date Line, but most of those
   places have been driven out of the regular retail game by the
   superstores and the Web. If you still have one in your neighborhood,
   you're lucky. I do, as it happens, but that is now unusual; the only
   place you normally find diaspora Chinese and Indians selling cheap
   PCs over the counter anymore is at computer fairs. (Usually they're
   doing it to publicize an Internet/mail-order business.)

   You can find good loss-leader deals on individual parts at these
   fairs (they're especially good places to buy disk drives cheap). But
   I call them a minor alternative because it's hard to get a custom
   configuration tuned for Unix built for you at a fair. So you end up,
   effectively, back in the mail-order or Web channel.
     ________________________________________________________________

8.4. Mail Order

   Internet buying makes a lot of sense today for anyone with more
   technical savvy than J. Random Luser in a suit. Even from no-name
   vendors, parts and system quality tend to be high and consistent, so
   conventional dealerships don't really have much more to offer than a
   warm fuzzy feeling. Furthermore, competition has become so intense
   that even Internet/mail-order vendors today have to offer not just
   lower prices than ever before but warranty and support policies of a
   depth that would have seemed incredible a few years back. For
   example, many bundle a year of on-site hardware support with their
   medium- and high-end "business" configurations for a very low premium
   over the bare hardware.

   Note, however, that assembling a system yourself out of parts is not
   likely to save you money over dealing with the Internet/mail-order
   systems houses. You can't buy parts at the volume they do; the
   discounts they command are bigger than the premiums reflected in
   their prices. The lack of any system warranty or support can also be
   a problem even if you're expert enough to do the integration yourself
   -- because you also assume all the risk of defective parts and
   integration problems.

   Watch out for dealers (Spectrum Trading for one) who charge
   ridiculous shipping fees. One of our spies reports he bought a
   hotswappable hard disc drive tray that weighed about 3 lbs. and cost
   $250 and they charged $25 to ship it UPS groud.

   Don't forget that (most places) you can avoid sales tax by buying
   from an out-of-state outfit, and save yourself 6-8% depending on
   where you live. If you live near a state line, buying from a local
   outfit you can often win, quite legally, by having the stuff shipped
   to a friend or relative just over it. Best of all is a buddy with a
   state-registered dealer number; these aren't very hard to get and
   confer not just exemption from sales tax but (often) whopping
   discounts from the vendors. Hand him a dollar afterwards to make it
   legal.

   (Note: I have been advised that you shouldn't try the latter tactic
   in Florida --they are notoriously tough on "resale license" holders).

   (Note II: The Supreme Court has ruled that states may not tax
   out-of-state businesses under existing law, but left the way open for
   Congress to pass enabling legislation. Let's hope the mail-order
   industry has good lobbyists.)
     ________________________________________________________________

8.5. Computer Superstores

   Big chain superstores like CompUSA give you a reasonable alternative
   to the Web. And there are good reasons to explore it -- these stores
   buy and sell at volumes that allow them to offer prices not far above
   the Web. (They make back a lot of their margin on computer games and
   small accessories like mouse pads, cables, and floppy disks.)

   Note, however: Avoid Best Buy. Horror stories about them are legion
   -- predatory salescritters, incompetent service, routine
   bait-and-switch tactics.

   One thing you should not buy remotely if you can avoid it is a
   monitor. Monitors are subject to significant quality variations even
   within the same make and model. Flatscreens haver this [roblem less
   than CRTs did, but you don't want a flatscreen with dead pixels. So
   buy your monitor face-to-face, picking the best out of three or four.

   Another good argument for buying at a superstore is that you may have
   to pay return postage if you ship a system back to the vendor. On a
   big, heavy system, this can eat your initial price savings.

   The only major problem with superstores is that the salespeople who
   staff them aren't very bright or very clueful (it's a sort of
   Darwinian reverse-selection effect; these are the guys who are
   fascinated by computer technology but not smart enough to be
   techies). Most of them don't know from Linux and are likely to push
   things like two-button mice that you can't use. Use caution and check
   your system manifest.

   But if you shop carefully and don't fall for one of their name-brand
   "prestige" systems, you can get prices comparable to
   Internet/mail-order with the comfort of knowing there's a trouble
   desk you can drive back to in a pinch. (Also, you can see your
   monitor before you buy!)
     ________________________________________________________________

8.6. Other Buying Tips

   You can often get out of paying tax just by paying cash, especially
   at computer shows. You can always say you're going to ship the
   equipment out of the state.

   A lot of vendors bundle Windows and variable amounts of apps with
   their hardware. If you tell them to lose all this useless cruft they
   may shave $50 or $100 off the system price.
     ________________________________________________________________

9. Questions You Should Always Ask Your Vendor

9.1. Minimum Warranty Provisions

   The weakest guarantee you should settle for in the mail-order market
   should include:

     * 72-hour burn-in to avoid that sudden infant death syndrome.
       (Also, try to find out if they do a power-cycling test and how
       many repeats they do; this stresses the hardware much more than
       steady burn-in.)
     * 30 day money-back guarantee. Watch out for fine print that
       weakens this with a restocking fee or limits it with exclusions.
     * 1 year parts and labor guarantee (some vendors give 2 years).
     * 1 year of 800 number tech support (many vendors give lifetime
       support).

   Additionally, many vendors offer a year of on-site service free. You
   should find out who they contract the service to. Also be sure the
   free service coverage area includes your site; some unscrupulous
   vendors weasel their way out with "some locations pay extra", which
   translates roughly to "through the nose if you're further away than
   our parking lot".

   If you're buying store-front, find out what they'll guarantee beyond
   the above. If the answer is "nothing", go somewhere else.
     ________________________________________________________________

9.2. Documentation

   Ask your potential suppliers what kind and volume of documentation
   they supply with your hardware. You should get, at minimum,
   operations manuals for the motherboard and each card or peripheral;
   also an IRQ list. Skimpiness in this area is a valuable clue that
   they may be using no-name parts from Upper Baluchistan, which is not
   necessarily a red flag in itself but should prompt you to ask more
   questions.
     ________________________________________________________________

9.3. A System Quality Checklist

   There are various cost-cutting tactics a vendor can use which bring
   down the system's overall quality. Here are some good questions to
   ask:

     * If you're buying a factory-configured system, does it have FCC
       certification? While it's not necessarily the case that a
       non-certified system is going to spew a lot of radio-frequency
       interference, certification is legally required -- and becoming
       more important as clock frequencies climb. Lack of that sticker
       may indicate a fly-by-night vendor, or at least one in danger of
       being raided and shut down! (For further discussion, see the
       section on Radio Frequency Interference above.)
     * Are the internal cable connectors keyed, so they can't be put in
       upside down? This doesn't matter if you'll never, ever ever need
       to upgrade or service your system. Otherwise, it's pretty
       important; and, vendors who fluff this detail may be quietly
       cutting other corners.
     ________________________________________________________________

10. Things to Check when Buying

10.1. Tricks and Traps in Warranties

   Reading warranties is an art in itself. A few tips:

   Beware the deadly modifier "manufacturer's" on a warranty; this means
   you have to go back to the equipment's original manufacturer in case
   of problems and can't get satisfaction from the mail-order house.
   Also, manufacturer's warranties run from the date they ship; by the
   time the mail-order house assembles and ships your system, it may
   have run out!

   Watch for the equally deadly "We do not guarantee compatibility".
   This gotcha on a component vendor's ad means you may not be able to
   return, say, a video card that fails to work with your motherboard.

   Another dangerous phrase is "We reserve the right to substitute
   equivalent items". This means that instead of getting the
   high-quality name-brand parts advertised in the configuration you
   just ordered, you may get those no-name parts from Upper Baluchistan
   -- theoretically equivalent according to the spec sheets, but perhaps
   more likely to die the day after the warranty expires. Substitution
   can be interpreted as "bait and switch", so most vendors are scared
   of getting called on this. Very few will hold their position if you
   press the matter.

   Another red flag: "Only warranted in supported environments". This
   may mean they won't honor a warranty on a non-Windows system at all,
   or it may mean they'll insist on installing the Unix on disk
   themselves.

   One absolute show-stopper is the phrase "All sales are final". This
   means you have no options if a part doesn't work. Avoid any company
   with this policy.
     ________________________________________________________________

10.2. Special Questions to Ask Web/Mail-Order Vendors Before Buying

     * Does the vendor have the part or system presently in stock? Mail
       order companies tend to run with very lean inventories; if they
       don't have your item in stock, delivery may take longer. Possibly
       much longer.
     * Does the vendor pay for shipping? What's the delivery wait?
     * If you need to return your system, is there a restocking fee? and
       will the vendor cover the return freight? Knowing the restocking
       fee can be particularly important, as they make keep you from
       getting real satisfaction on a bad major part. Avoid dealing with
       anyone who quotes more than a 15% restocking fee -- and it's a
       good idea, if possible, to avoid any dealer who charges a
       restocking fee at all.

   Warranties are tricky. There are companies whose warranties are
   invalidated by opening the case. Some of those companies sell
   upgradeable systems, but only authorized service centers can do
   upgrades without invalidating the warranty. Sometimes a system is
   purchased with the warranty already invalidated. There are vendors
   who buy minimal systems and upgrade them with cheap RAM and/or disk
   drives. If the vendor is not an authorized service center, the
   manufacturer's warranty is invalidated. The only recourse in case of
   a problem is the vendor's warranty. So beware!
     ________________________________________________________________

10.3. Payment Method

   It's a good idea to pay with AmEx or Visa or MasterCard; that way you
   can stop payment if you get a lemon, and may benefit from a
   buyer-protection plan using the credit card company's clout (not all
   cards offer buyer-protection plans, and some that do have
   restrictions which may be applicable). However, watch for phrases
   like "Credit card surcharges apply" or "All prices reflect 3% cash
   discount" which mean you're going to get socked extra if you pay by
   card.

   Note that many credit-card companies have clauses in their standard
   contracts forbidding such surcharges. You can (and should) report
   such practices to your credit-card issuer. If you already paid the
   surcharge, they will usually see to it that it is returned to you.
   Credit-card companies will often stop dealing with businesses that
   repeat such behavior.
     ________________________________________________________________

10.4. Which Clone Vendors to Talk To

10.4.1. Some pans

   Gateway: may also be a vendor to avoid. Apparently their newer
   machines don't have parity bits in their memories; memory is tested
   only on reboot. This is dubious design even for Windows, and totally
   unacceptable for Unix.
     ________________________________________________________________

10.4.2. Some picks

   In early August 2001 I designed an `Ultimate Linux Box' with Gary
   Sandine and John Pearson of Los Alamos Computers; you can
   [http://www.catb.org/~esr/writings/ultimate-linux-box/] read all
   about it These guys know what they are doing and are fun to work
   with. If you need a high-end Linux workstation, or your laboratory
   needs a computer cluster, talk with them.
     ________________________________________________________________

11. After You Take Delivery

   Your configuration is custom and involves slightly unusual hardware.
   Therefore, keep a copy of the configuration you wrote down, and check
   it against the invoice and the actual delivered hardware. If there is
   a problem, calling back your vendor right away will maximize your
   chances of getting the matter settled quickly.
     ________________________________________________________________

12. Software to go with your hardware

   I used to maintain an entire separate FAQ on Unixes for 386/486 and
   Pentium hardware. Times change, industries evolve, and I can now
   replace that FAQ with just three words:

   Go get Linux!

   Note

   FreeBSD or OpenSolaris are currently niche choices, but if they offer
   something you need that Linux doesn't, don't let me stop you from
   trying one or both of them.
     ________________________________________________________________

13. Other Resources on Building Linux PCs

   The [http://www.pctechguide.com/] PC Tech Guide offers pretty
   comprehensive descriptions of PC hardware technologies.

   The Caveat Emptor guide has an especially good section on evaluating
   monitor specifications.

   Anthony Olszewski's Assembling A PC is an excellent guide to the
   perplexed. Not Linux-specific.

   Tom's Hardware Guide covers many hardware issues exhaustively. It is
   especially good about CPU chips and motherboards. Full of ads and
   slow-loading graphics, though.

   The System Optimization Site has many links to other worthwhile sites
   for hardware buyers.

   Christopher B. Browne has a page on
   [http://linuxfinances.info/info/linuxvars.html#VARS] Linux VARs that
   build systems. He also recommends the Linux VAR HOWTO.

   There's a Building Your Own PC page. It's more oriented towards
   building from parts than this one. Less technical depth in most
   areas, but better coverage of some including RAM, soundcards and
   motherboard installation. Features nifty and helpful graphics, one of
   the better graphics-intensive pages I've seen. However, the
   hardware-selection advice is out of date.

   The Linux Hardware Database .

   The Silent PC Reviews site has lots of good material on building
   quiet PCs.





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