response 25 of 205:

Mar 30 23:00 UTC 2002

We have 2.5 pentiums from Tim Ryan that we have not found a use for.
They tend to run hotter and need fans.
I solved the computer problem by starting over with an ATT (from Tim, one of
about 50 he donated from Borders' discards) and putting the files on that.
Lynx runs fine there, just like on my office computer which is the same.

On the second 4M RAM computer (it won't recognize a second 1M SIMM, if I add
it I get 1 total instead of 4+1) with one serial port (Com1), controller card
where we don't know how to disable Com2, and sometimes internal modem on Com3
(with Com1 unplugged) I could run PCPlus or Kermit but Lynx will not dial
(unless I change the init string from one that worked with it before) and if
it does dial it wont' connect, and the one time out of 30 it did connect it
would not find the nameservers.  The nonconnect problem occurs with lynx with
all my computers but only half the time.  Something timing out?

Anyway, I have decided this computer will never work with lynx and we will
use it at the building site to draw CAD drawings of the porch.

The ATTS seem to always work (don't have the printer problem that we had with
three other computers and numerous controller cards, work with Lynx, read
floppy disks that other computers won't).  The Pentiums from Tim are ATT.
The only thing I would appreciate more speed for is dealing with images, and
I can stand to wait 20 sec once in a while.  (One program insists on
converting all 2-color images to 8-bit 256 color while I wait, before it will
display them).

Are other people using computers older than pentiums, and what for?

I guess I ought to retitle this item 'obsolete computer hardware'.

response 27 of 205:

Mar 31 02:16 UTC 2002

Most early computer hard drives had one-off interfaces.  That is, the
interface would be designed for that particular model of drive, and the
next generation model would have a completely different interface.
Typically there would be a separate controller, in some cases occupying
a complete 6' tall 19" rack, which would contain the electronics needed
to go from the disk interface, to whatever peripheral interface the
computer supplied.  Typically, the interface on these early 1-off
designs would include separate "control" and "data" busses.  The control
bus would include signals to select drives, heads, plus signals to step
the arm in or out to the desired cylinder.  The data cable would include
the actual data being send to/from the drive and associated timing
signals.

One typical peripheral interface was the IBM channel interface, which
used 2 really big fat cables "bus and tag" to connect between the
channel interface, and individual device "controllers".  The channel
interface proper was capable of doing DMA into main memory independently
of the CPU, and ran short channel "programs" that directed the follow of
data and commands to and from devices.

Several 3rd party disk makers realized that 1-off disk interfaces was
not the way to go, and banded together to create the SMD (storage module
disk) standard.  One advance in SMD was that instead of supplying
stepper motor pulses, the drive itself would move the arm to the proper
position; the interface included a parallel interface on which the
cylinder could be supplied.  The data cable only transfered one bit at a
time, and this became something of a problem as drive capacities went
from 5 megs of removable storage, to 600 or more megs of non-removable
storage.  SMD drives were particularly popular in the minicomputer
market.

The shugart associates SA1000 series was one of the first hard disks to
reach the microcomputer world.  The SA1004 was an 8" 8M drive, which
used a fairly primitive interface design.  Based on earlier floppy drive
interfaces, it was also very typical of the "one-off" designs of earlier
mainframe disk technology.  It used a 50 pin ``A'' cable for control
signals, plus a 20 pin ``B'' cable for data.  Typically the control
cable was bussed in common to all disk drives, while the data cable
would be individual cables going from the controller to each drive
separately.  While the SA1004 was popular in its own right, it was also
important as the starting point for 2 disk interfaces, the ST-506 & SCSI
interfaces.

SCSI originally started off as SASI, and it was in effect the
realization of mainframe disk architecture.  The channel interface of
the mainframe was called a "host adapter" in the microcomputer, and the
device controller became a separate card which went between the SCSI
interface and one or more physical disk drives.  As LSI logic became
cheaper and better, it became possible to incorporate the SCSI interface
directly on the disk.  The original SCSI interface used a single 50-pin
cable, and allowed for an 8-bit transfer path, and up to 7 controllers
(plus the host CPU) on the SCSI bus.

The ST-506 drive came out rather soon after the SA1004, and was the
first popular 5.25" drive.  It only held 5 M.  It used essentially the
same signalling standard that had been designed for the SA1004, but on
only 34 pins, because 5.25" didn't leave enough room on the back of the
drive for anything more.  Like the SA1004, but unlike virtually all
drives that came after it, the ST-506 had a stepper motor interface and
no on-board CPU; the controller was responsible for scheduling stepper
motor pulses.  The ST-412 and successor drives used minor modifications
to what became known as the "ST-506" bus standard; one of those
modifications was the notion of "buffered" seeks, which essentially
meant the controller fired off a bunch of pulses all at once and the
controller would accumulate those in a counter and use those to drive
the actual stepper logic.  The ST-412 had a microprocessor that was
dedicated to just performing those stepper motor calculations.

The IBM PC XT used the ST-412.  The XT controller was capable of doing
DMA to main memory, necessary because of the slow speed of an 8088 at
4.77 Mhz.  The controller also came with its own "disk bios", which
patched into the main bios and extended the disk "INT" interface to
support the hard disk.

The IBM AT came originally with a 20 M drive.  It also came with a new
disk controller.  The 286 in the AT was capable of doing "string" I/O,
which was much faster than DMA on the XT.  The new disk controller used
these "string" I/O instructions instead of DMA, so was both faster and
cheaper.  (A DMA design would have been faster yet, but more expensive).
The original SA1004 interface and later ST-412 allowed for up to 4
drives per interface controller, but on the AT, this was further limited
to just 2 drives.

Later on, IBM and several other companies introduced ESDI, which was
basically an improvement on ST-506/412.  It used the same 34+20 pin
cable scheme, but (I believe) replaced the buffered seek logic with an
actual binary number sent in parallel - much like SMD.  ESDI was never
really popular, and I think the reason is right around this time, the
market became flooded with much cheaper RLL encoded drives using the
earlier ST-506 style interface.

To explain RLL, we have to go back a bit and explain FM and MFM.  The
earliest drives stored data as a series of interleaved timing and data
pulses.  Each pulse had a separate leading & trailing edge, and data
pulses were only present if the associated data was a logic ``1''.  This
was easy to decode in hardware, but expensive in terms of storage.  The
first advance was MFM -- in which each signal *transition* was used for
data and timing alternately.  This could record twice the storage of FM,
at the cost of only a few more gates for the "data separator", the gizmo
that separated the data from the timing signals.  Most early drives,
including SMD and most of the early ST-506 drives, used this.  RLL was
another step in advance of this -- instead of using half the signal
transitions for timing, a different scheme was devised by which 7 data
bits could be stored in 9 signal transitions - using a table in I think
guaranteed at least 2 signal transitions in any possible group of 9
signal transitions.  This was another 50% improvement over MFM, at the
cost of only a slightly more complex data separator.  This scheme could
in fact work with drives originally designed to be MFM, at the cost of a
slightly more expensive RLL controller, which had a data separator that
was slightly fancier than MFM.

RLL and buffered seeks were but minor improvements in storage
optimization.  The drive makers knew that they could get even more
improvement in storage by other tricks, such as storing more sectors in
the outer tracks, but this would have broken the ST-506 interface in
ways that would not have been easy to fix in software.  Rather than do
this, the PC disk world decided to instead move most of the
functionality of the disk controller onto the drive, leaving only the
minimum behind necessary to drive the I/O bus.  The interface these
drives would present to the world would instead be based on the IBM AT,
and so this was sometimes called the ATA interface rather than IDE.
Like the earlier AT drives, this interface would only support 2 drives,
and programmed I/O generally using the "string" input/output
instructions of the CPU.

response 29 of 205:

Mar 31 03:25 UTC 2002

IDE has gone through several generations.  There is EIDE, and
"UltraDMA", and several other buzzwords.  My understanding is that the
latest drives in the IDE technology line are capable of DMA but not of
overlapping seeks.  For one drive, this is fine; for a server with 8
disk drives, IDE is still hopelessly outclassed by SCSI.

response 31 of 205:

Apr 1 04:24 UTC 2002

To each his or her own.  Personally, I could not revert to 10 year old
hardware, dialup modems and text based applications.  When they were
state of the art they were so much better than what preceeded them
(ie pencil and paper) but by todays standards are down right primitive.
You might want to rescue a landfill bound Pentium-133 or thereabouts.

response 33 of 205:

Apr 1 14:29 UTC 2002

My home network setup contains the following:
1 486DX2/66 running as firewall/router
1 Mac clone (PPC603e/160)
1 Pentium-100 (currently in flux; destined to be Linux test-bed)
1 Pentium Pro-166 (Win NT)
1 Pentium-133 laptop (Win98)
1 brand-new (just received on Friday) Athlon-950 being set up as a FreeBSD
server which will be externally visible (replacing the dedicated server I
rent)

How much of that do most people consider "obsolete"?

response 35 of 205:

Apr 1 16:21 UTC 2002

        I've got some seriously obsolete hardware at home.  As in a DEC
Rainbow.  But it'd be pointless to try to upgrade the machine to the point
to which it could actually format its' own floppy disks.

response 37 of 205:

Apr 2 00:59 UTC 2002

I have a TRS-80 Model I sitting a few feet away from me.  The character 
generator has a stuck bit, and the monitor needs some refurbishing, but 
otherwise it seems ok.  It has 16kb RAM.  Very obsolete.

response 39 of 205:

Apr 2 04:30 UTC 2002

For those on a semi-budget, I was at Property Dispo this morning and noticed
a few iMacs being sold "as-is" for $100/ea, no keyboards.  Most were labelled
"bad CD drive".

response 41 of 205:

Apr 2 07:31 UTC 2002

If u want to install PTSDOS send me a mail to : c4f4@mail.univ.kiev.ua
& I'll find this historical OS and send u.

About old machines like z80,286,386,486: refresh rate on this machines
is very dradfull(5 hours in front of the desctop and u ll blind:)).

My friend constructed radar emulator for russian detector on the base
Z80. It is cool but realy slowly.

response 43 of 205:

Apr 2 14:26 UTC 2002

Heh.  Apparently new CD drives for iMacs go for $150.  Oh well, even with that
and a new keyboard & mouse (say $80 for a cheap pair) it's a pretty good deal
if you do your own parts swapping and like Macs.

response 45 of 205:

Apr 2 17:21 UTC 2002

Depends on what you want to do with it, too.  iMacs can be network booted.

response 47 of 205:

Apr 3 11:53 UTC 2002

Why u using licensed copyes os programs? How companies can control software,
wich u use on your computer at home? Hacker's versions of software products
cost less than any other disc.
I have one example: disc with CorelDraw10,Photoshop6.0,PowerQuest Partition
Magic 6.0,WindowsMe and other small programs costs 1.25$ in Ukraine. So we
buy this discs(not licensed). If u know prices on this soft u can feel
difference. Hachker's software works like licensed( 3 years ago we installed
Win98 from licensed disc. This "powerfull OS" failed after two days:).It was
first and last time when I installed licensed programs:).

I don't understand: why u using licensed programms? Who will come and
control u? 

response 49 of 205:

Apr 3 15:38 UTC 2002

John said it, not me!
 
#46> While many people do indeed use "whether I'm going to get caught" as
their sole measure of whether or not to do something, others use a more
subjective scale, trying to balance, "it's proper to pay for software that
I use, and for which the producer expects payment," with "software companies
are huge commercial monstrosities that don't need any more money." Differing
people have differing, but viable, resolutions to that conflict: Some only
pay for smallscale or shareware, others choose to pay for everything, and so
on. Sindi falls in the latter group; the majority of vocal posters on here
appear to belong to the former, and I'm a fence-sitter. ;}