[conspire] Last Year's Supercomputer

[Heather Stern]

> > Seduced by the Friday Fry's ad, I'm planning to spend 
> > my last $300 on upgrading my pentium 133MHz/64MB computer....
> 
> Yeah, it's time, isn't it?  ;->

I usually upgrade these sorts of systems by leaving K and Gnome out of
the distro I install on them.  Funny how much faster than MSwin they
seem then.  

But yes :) 

>> [RAM pricing]
> [good RAM, bad RAM, Linux' behavior about same]

The fact that Linux has means to work around iffy RAM, and can be
patched to actually avoid really bad spots in it, doesn't really excuse
buying iffy RAM unless you're close to broke.

That marvelous computer described below will end up bottlenecked on RAM
most of the time.  ECC RAM may actually be slightly slower in some
circumstances - and if you think you'll encounter those, then it's your
call whether speed or perfection-of-bits is most important to you.

As Rick says, the worst danger is some sort of slow corruption that
sinks into a database or something, leaving you with a queasy feeling
and bad backups later.

> > $100 AMD Athlon XP 2400+ CPU 1.93GHz, 266Mhz bus, 
> >      128KB L1 cache, 256KB L2 cache.
> 
> God knows this is a fast enough CPU, and then some.  I'm sure you know
> that Linux is _not_ a CPU-intensive operating system, and for general
> computing purposes, I'm still perfectly happy with my PII and K6 systems.  
> The general run of Intel-style hardware tends to be system-limited in
> other areas like RAM, I/O, video speed, and mass storage much more than
> it is CPU-bound, because the units are system-tuned to match the heavy
> CPU demand of Microsoft OSes.
 
What I refer to one one of my older systems as "co processor'd up the
wazoo".  Yes, this philosophy can work wonders.

Scattering your workload across multiple SCSI spindles can allow the
SCSI controller to put drives in disconnected mode and take advantage
of a few extra-tiny CPUs more.

Havign a way-cool enough video processor, in addition to just dealing
with that fussy GL stuff for you, can make a number of video uses feel
hyperfast - even if the CPU is still crunching away under the hood,
running its little hamster self into a daze.  For many users the
*appearance* of speed is weirdly, more important than clock time.

RAM bottlenecks mentioned above.

If you plan to print, make sure your parallel port is up to snuff (not
hard) or get a networked printer (network speeds are often faster, esp.
on a private network, and the smart printer is another CPU to aid you).

Also, careful software configuration may allow you to free even more
CPU, but swap is still swap.  If you'll be doing a lot, you'll want RAM
to bear the context switches, not your hard disk :)

Finally, consider what you'll be doing with it.  Grpahic arts really
does need some CPU oomph, and lots of RAM, because photographic work
takes bunches of memory.  Dev work, well, it varies, but my "slow" P550
with 512M RAM (yeah, I know, it's middle-aged and frumpy now ;P)
crunched the LNX-BBC fulle build at the same overall speed as a much
faster CPU (900 I think) with less RAM (128 M).   I assume in matters
of scale that this CPU/memory trade off will continue to apply.   I've
also been advised that while a dual CPU setup helps builds nicely - as
the build crunching along gets tossed to the second and "normal"
operating functions stay on CPU 0, reducing an internal bottleneck
within Linux - that more CPUs than this isn't worth much unless you're
working on things that really use the split nature.  Finally, I've heard
baaaad things can happen to people who get dual CPUs without getting
them at the same time - apparently they are far better behaved as twins.

I approve of a fast CPU but wonder if it'll run hotter (temperature
wise) without giving you the bang for your buck.

> >      ECS K7S5A Pro motherboard, SiS 735 chipset
> >      http://www.ecsusa.com/products/k7s5a_pro.html
> >      5 PCI, 2 DDR -- 

Has it enough IRQs to go around all the goodies you might plug into it,
or will only about 4 of these slots be useful at a time?

>> total 1GB RAM,

yum.

>>  266 MHz FSB,
> [There are much faster memory buses available]

Hmmm :/

If a motherboard has a seperate, faster memory bus from a reasonably
fast PCI bus does this make notable improvement?  (I'm not sure which
this represents, or whether it's combined)

>> AC'97 sound, 

ok, but you'll want better details on the chipset than that.  Lots of
vendors use that codec.

[moved]
> The sound chipset is not known to me:  C-Media CMI9738/4CH AC'97 CODEC 
> You may or may not have an easy time with that.

I haven't heard of it either, though this may not mean much - usually
I'm soaked in laptop discussions, and that doesn't sound like a low
power model.

>>      10/100 NIC, 

Which one?

[moved up]
> The built-in ethernet is a RealTek RTL8201BL.  For that, I believe
> you'll use the 8139too driver, though that's just a guess off the top of
> my head.  RealTek chipsets aren't great, in general, but they're OK.

Oh. Sigh.  

In the case of any motherboards with "really cool" integrated
components, I always find myself wondering if their BIOS or some jumper
settings allow turning them off.  Jumpers you can learn from the little
book with the motherboard.  As for BIOS usually nothing but booting one
up can tell you, sadly.

>> 4 USB 2.0, 

yum. 

>> UDMA 100 IDE, 

which chipset?

>> 4X AGP.  

normal these days. 

> [...] No idea what sort of price
> premium applies for that and the matching RAM, but traditionally that's
> been where the biggest difference in effective computing performance has 
> occurred over the last decade -- that and video performance.

Video performance is often about memory speeds within the videocard,
too.
 
> Note that your system doesn't have a lot of RAM sockets.  You'll want to
> select carefully whatever RAM you put in them, because expansion may
> be problematic.

Check if you're going to be forced to use low-height RAM, too. 

> >   50 512MB 266MHz DDR memory stick (guessing on Fry's price)
> >      http://www.pricewatch.com/
> 
> I personally don't feel happy with Fry's RAM.  I'd get RAM (and CPU, for
> that matter) from SA Technology, www.satech.com .
 
Fry's prices for these two parts usually suck, but they often have some
of the off varieties of RAM in stock.

Fry's, the fast food of computer parts.  I'd like a burger with that.

(yes, you can stuff this in your fave quotes file if you like ;> )


[Me too on the Tekram SCSI looking like good stuff]
 
> >   67 Power supply - PC Power & Cooling 
> >      Turbo-Cool 350ATX/ATX12V noise 42dB(A), or
> >      Silencer 275 ATX/ATX12V noise 34dB(a)
> >      http://www.pcpowerandcooling.com
> >      Can these be bought locally?
> 
> Yes.  Excellent choices, and your motherboard & hard drive will thank
> you.  Central Computer, Santa Clara.

:)  (she says, scribbling it into a notepad for a pal of mine upping his
power supply)

> >   ?? Case
> >      Will a current ATX motherboard and power supply fit in a 
> >      1997 ATX case?
> 
> Yeah, probably.  I'd use a tower case for heat dissipation, but that's
> me.

Just make sure if you get a new case to look at all its features, not
just the bubblegum looks they're starting to have these days. 

> > or   
> >   60 Enermax case and 330W power supply, four 5" & five 3" bays
> 
> I'd want the PC Power & Cooling power supply.  

330 W isn't worth much on a hotter system anyway.  The problems you can
cause yourself by giving the system only barely enough power instead of
plenty-and-to-spare cause just as many heisenbugs as the aforementioned
poor quality RAM.  Except that they have a better chance of leaving
behind permanent damage to underpowered drives.

This applies to old systems as well as new, and *especially* to reallly
old systems.  I didn't realize this until I swapped out 3 pre-historic 
drives for a merely wimpy old one and listened to the power supply stop
whining to keep up.  So keeping it over-powered will probably help
silence the cabinet, too.  

Of all the parts you can dream of replacing with better someday, power
is a serious pain to swap out, and you'd really rather get to ignore it
for years on end.  Get a decent power supply at the get-go.
 
> but a careful choice of system case will also help.  

For my happy desktop and dev station, I got a case which has a built in
space for an extra fan.  The fact that this spare fan sounds like a jet 
engine when plugged in is a replaceable feature;  the shape of the case
being prepped already isn't. 

> >   20 (after rebate) Pacific Digital Mach52 CD-RW 52x24x52 IDE
> >      http://www.pacificdigitalcorp.com/products/522452ide.htm
> 
> Gee, I wouldn't.  I'd get a SCSI CD-RW from Ricoh, Yamaha, or Toshiba.
> Yes, I know I'm a notorious SCSI bigot.  However, I keep reading
> people's complaints about their entire systems freezing up just because
> of a media problem during CD burns.  This is because of the way the
> ide-scsi shim driver operates:  If it has a problem while in
> I/O-addressing mode, your operating state is toast.  (Also, software
> setup for SCSI burners is dead-easy.)

In the land of IDE burners I have to say the following -

0) append="hdc=ide-scsi"
   {modprobe or modutils or modules.conf} ide-scsi sg
   cdrecord -scanbus to learn where it is
   set a file in /etc/defaults to feed cdrecord all that obvious stuff

1) the immed flag can really help but I hope you have a brand that
   doesn't need it to stay well behaved.  the immed flag does a fast
   return on a number of common features which reduces the I/O window
   you could get trapped in.

   1.a) if you do get trapped be patient; unlike some other kinds of 
        device wedging, CDs have been known to return after 8 to 10
        minutes.

2) my vaguely recently purchased burner is a GCE-8400N - merely 40x
   but I'm very happy with it.

3) Don't buy Memorex media.  It sucks asteroids through nanotubes.

> >    8 50 CD-R blanks, 52X, GQ brand
> >      Are these reliable? 
> 
> God only knows.  But blanks are so cheap, who cares?

These are an OK brand.   I use Phillips.

If you plan to play with minidiscs or bizcard media bear in mind that
they aren't rated for nearly this good.  I burn my favorite minirounds
at about 12x, but 40x makes coasters.

> > Various AGP 4X video cards are available for $25, but for now 
> > I'll keep the RIVA TNT PCI card with the fan blowing on it.  

RIVA has its headaches, but if you're used to them, it's your baby.
I have numerous video cards which have outlasted the rest of their
system package.

> > Is AGP 4X faster than PCI anyhow?

It's a memory bus thing, so see the above comments about RAM
bottlenecking for a start.

AGP is a means to allow cards to do bulk memory transfers, so you can
think of it as vaguely analogous to "burst mode" features that real SCSI
or UDMA/IDE offer over a boring old IDE bus.   People who geek out about
AGP wouldn't be asking about "4x" - which is normal nowadays - they'd be 
asking about its memory aperture.  This can be learned in its BIOS, if 
you get a chance to see the motherboard in a machine and turned on.

> As always, it depends on what you're doing.  Obviously, you're not one
> of those 3D gamer guys, or you'd have said other things entirely.  ;->
> 
> Me, I'd probably just look around for a used Matrox G400 AGP.  But I
> don't do anything video-intensive.  (There's nothing wrong with your
> RIVA TNT, thougn.)

Matrox are well behaved video beasties.  I'm afraid I had to suck up to
an ATI Radeon to handle my powerful monitor - because it has a DVI
connector.

An increasing number of games want video cards with 128 MB of RAM.
Yowza.  I settled for merely 64 MB and it works fine for me - and
remember, I said I'm into graphics.  Standard system memory is handling
things just fine.  What you definitely need is enough total bytes to
cover your expected pixel size times color depth, and a little bit of
room to spare for textures storage.

X will tell you if you haven't got enough video memory to do what you
asked, and downgrade the pixel width/height to fit within what your card
can do.

Finer quality video cards have a very wide dotclock range.  Sadly this
is another one of those qualities that's easy to ask the card in a
running system (well, kindasorta easy) and may or may not be in its
docs.

  . | .   Heather Stern                  |         star at starshine.org
--->*<--- Starshine Technical Services - * - consulting at starshine.org
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