>I am completely unfamiliar with S-100 systems, so could you
please
>explain... were S-100 technologically superior to PCs (i.e. IBM
>PC 5150), or just aesthetically? As far as I know, they used an
>older processor...
S-100s started out with an Intel 8080, then Zilog Z80. That was
pretty much the end of the 8-bit version, although there were
several other variants (8085, NSC 800, Hitachi 64180, Signetics
2650, etc.). Hmm, I never recall seeing a 6502 or 6800 CPU
board. Once the S-100 was standardized around the IEEE-696
specifications the good 16 bit systems started appearing. One
of the earliest was the 8086 by Seattle Computer Labs (IIRC).
Famous because it came with the ancestor of MS-DOS, which
Microsoft later bought for their IBM PC deal. You might say all
the PC software now in existence owes its existence to the
S-100....
Anyway, there were quite a few 16-bit systems. Many 80286
variants, including a nice one by Macrotech, a dual Z80H/80286
CPU. There were several 68000s, TI 9900, National 32000, Zilog
Z8000, and a variant on the Western Digital LSI-11 bit slice
chipset called Alpha Micro. The AM ran its own multi-user
operating system, very reminicent of RT-11 (there was a strong
DEC influence there).
Was the S-100 technically superior? Well, if you go by the
IEEE-696 specifications then compared to either the XT or AT it
was quite a bit better. Maximum memory was 16MB (24 bit
address, 8 or 16 bit data path), 8 interrupt levels (open
collector! which meant multiple boards could use the same IRQ),
16 DMA levels (still better than the 7 DMA levels on the current
PC). Most 286 based systems ran up to 8Mhz reliably, some made
it to 10 or 12 Mhz (compared to the original AT at 6Mhz). Even
better, it was common practice to use static RAM memory on the
better business systems. If that term doesn't sound familiar,
cache memory on modern PCs is static RAM. The significance is
that there were no wait states or lost cycles to refresh. Think
of how fast your Pentium would run today if all 64MB of RAM was
cache, not DRAM.
S-100s were also very expandable. Motherboards usually had
between 18 and 22 slots for full sized machines. You could put
a lot of RAM, serial, and disk controllers in that many card
slots. I built custom 286 based multi-user systems that
supported 10 or more users running production business work.
The response time compared quite favorably to contemporary low
end DEC PDP-11s, and for a fraction of the cost.
S-100s were also early adopters for much of the current crop of
PC peripherals. Networking, using ARCnet at 2.5Mbps over coax.
Digital Research supported network access to disk drives using
CP/NET on top of MP/M II. No, it wasn't TCP/IP, but it still
compares quite well to a basic Netware system. Disk drives,
both the 5.25" floppy and the 5.25" hard drive showed up on
S-100s before PCs. S-100s using MP/M II could support disk
drives up to 512MB, long before MS fixed the 32MB barrier in the
XT and AT.
The S-100 did have some drawbacks, mostly from the weird control
signals the CPU had to generate (anyone remember how difficult
it was to simulate a PSYNC on a non-8080 processor?). It
suffered terribly from early failures to standardize the bus.
Many of the 8-bit systems had unsolvable compatibilty problems.
(on the other hand, it did make for some extra pocket change for
struggling college students who knew how to tune an S-100 to
make everything work :) )
Another problem was the unregulated power supply. Unregulated
+8 and +/-16VDC was run over the bus itself, right next to
signal lines. Every board required it's own regulation, which
could take 20% or more of the board space, as well as being a
nightmare to keep cool. If you see early pictures of loaded
IMSAIs, the cover was always off. This was a necessity, the
heat was too much with the cover on. I had to use a 16" fan to
keep mine running with 64KB of 2102 based static RAM (not 21L02s
BTW, they cost more than the fan did).
The single worst problem was the absolute lack of any hardware
standardization beyond the 696 specs. There were no I/O
addresses for anything. One manufacturer might use a WD 1791
floppy controller at port 7xH, another would use the NEC 765
floppy controller at address 9xH. There were no standardized
BIOS ROMs either. Systems came with some basic boot ROM for one
particular disk controller/serial interface, and that was it,
everything else was supported by drivers in the machine specific
version of the OS. A boot disk for an Altos wouldn't run on a
North Star, not even close. For those who think it an evil that
the world has standardized on the Wintel architecture for PCs,
trust me, the other choice is far worse.
>Was it just an issue of being used to them?
Sure, but then if you wanted a good hardware oriented micro with
lots of support from 3rd parties, in the mid 70s the S-100 was
the only choice. You could get a board to do just about
anything, tho you had to program it yourself. Nearly all boards
came with schematics, if you didn't like the design or it wasn't
quite compatible, you could cut traces and rewire to your own
choosing. My own IMSAI is far from a standard out of the box
model.
>As for laissez-faire, I never have believed in it. It makes
society
>too concerned about money. This is proven when complete crap
hardware
>is released now, and people don't care because it's good
_financially_
You don't like the profit motive? *gasp* That's, well, that's
just plain un-american (understandable and excusable if you
happen to be european tho).
Jack "show me the money" Peacock
<ISTR an article on alt.folklore.computers a year or so back, giving the n
<the lawyer who sent the first officially-recorded unsolicited email spam.
<he lost his account. I can't remember the details, so it might be hard t
<(and I'm not sure of the details, but 5-6 years ago sounds about right).
The landmark was right around the time I left DEC (1993).
I'd been on the 'net via their gateways since before '87. I was greatly
sadend when I the words went out the internet would permit commercial
ops.
Allison
> From: Wirehead Prime [mailto:wirehead@retrocomputing.com]
> Not all of us ISPs are evil and unconcerned with the
> Internet. I run a
> good, solid business with a 95% customer retention rate
> calculated over 4
> years. I don't do business with spammers or pornographers and have
> written my contracts so that I can immediately terminate any customer
> that violates Netiquette. I've been yelled at about that...that I'm
> ...
> Some of us who started in the early days of commercialization
> wanted the
> Internet to be like we were used to it being when we used it
> from college
> or businesses in the late 80s and early 90s. You can thank
> CompuServe,
> AOL, and hordes of know-nothing little ISPs with wads of cash to
> substitute for business sense for the current situation.
It's easy to blame novice users and get rich quick spammers, but I can't
agree with you. I look on the 'Net as evolution in action. Right now
we have the feeding frenzy of spammers drowning us in unwanted email.
The easy, and wrong, solution is to force them to stop. The right way
is to make it uneconomical for them to send spam. How? I don't really
know, I just ignore it, sort of like background static noise on a
shortwave radio.
But consider, what kind of response rate do spammers get? Now junk
snail mailers have to actually pay per piece, although at a reduced
rate. They have to make the junk mail attractive to readers so they can
get a high enough response rate to justify the mailing. Maybe we need
the same mechanism for mass commercial postings. In other words, the
ISP specifies in the terms of service that mass commercial mailings (aka
spam) are charged at the same mailing rates as the local post office,
something around 20 cents per item. Now you have a legal means to get
back if the ISP catches a spammer, because they are liable for the
contracted costs.
And just to bring it back on topic...when consumer PCs came out (IBM,
PET, Atari, Apple, etc.) those of us who built and used "real" micros
(S-100s of course) lamented that fact that the microcomputer market was
being overrun by large corporations bent on destroying the laissez-faire
market of the mid 70s. Sound familiar?
Jack "I use an IMSAI, not those toy computers" Peacock
On Apr 14, 1:36, Tony Duell wrote:
> Pete Turnbull wrote:
> > Isn't a DX11 an IBM channel interface? Originally a big cabinet with a lot
> > of flip chips and lamps? I've seen two, working.
>
> That's right.
> Where on earth did you see one of those?
A few summers ago, Leeds University were getting rid of an Amdahl mainframe and
supporting equipment, which included several PDP-11s and two DX11s. I managed
to invite myself along with a couple of friends, one of whom acquired a
complete working DX11 and one in bits, plus cables. I think there was a doc
set as well. I got an 11/73 with a much smaller 3rd party Qbus version, which
I've since passed on, as the same friend actually has a 360 which he's hoping
to get going again.
> I really must cable one of mine up again, re-read the printset, and
> figure out what on earth to use it for...
First find a System/360 :-)
Then find a lot of space with a strong floor. Jim put his in a room which he'd
prepared with a false floor. Unfortunately the materials supplier had provided
the wrong grade of board, and apparently the main unit rolled in OK, but when
it came to its proper position, there was a crunching sound, and the 360
settled a few inches as several of the castors punched through the floor
panels. Jim wasn't too pleased (he did get it fixed, though).
BTW, the little DX11-alike in the 11/73 was accompanied by a "Camtech Ethernet
QBus Interface". It's a quad-high Q-bus board, with a 68000 and a 68450 (PGA
types), a 68230, 68564, some memory, and the usual AMD ethernet chip set.
There's a 20-pin header for the ether i/f, and two 26-pin ribbon cable
connectors near a pile of 26LS30s and MC3486's, so I assume this is some sort
of terminal concentrator or PAD (there's also a 2.4576MHz xtal, which implies
standard 300/600/1200... baud rates). I was told the firmware didn't support
TCP/IP, but some other protocol. Anybody know what that would be? Is it any
use for anything? Can it be changed to use TCP/IP?
--
Pete Peter Turnbull
Dept. of Computer Science
University of York
I have an IBM AT Multiprotocol Communications Adapter, new, in the
original carton, with the original vinyl booklet and 5.25" disk for
sale. It's only missing the cable which can easily be made from two 25
pin d-sub connectors (1M, 1F) and a piece of cable.
Anyone in the US want or need this? $10 which includes the postage. It
goes to the big dumpster in the sky if no one lays claim to it by Friday
the 10th.
--------------------------------------------------------------------
Russ Blakeman
RB Custom Services / Rt. 1 Box 62E / Harned, KY USA 40144
Phone: (502) 756-1749 Data/Fax:(502) 756-6991
Email: rhblake(a)bbtel.com or rhblake(a)bigfoot.com
Website: http://members.tripod.com/~RHBLAKE/
ICQ # 1714857
* Parts/Service/Upgrades and more for MOST Computers*
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Does anyone have an ESDI hard drive for a PS/2 Model 70? I have a
60, but want to replace it with a 120 (the other size the PS/2 came
with; I don't want to risk having an incompatible hard drive). I
don't know if others are compatible. However, this is a wide single
ribbon connector.
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<programmer would inadvertantly spool a "binary file" to a lineprinter.. W
<had
<an individual, in the Maynard (Ma. DEC), at one point in time, spool a jo
<to
<the printer that hung off the DECsystem 1090 (serious tractor feeds on th
<unit!) that took a day and a half, and consumed 24 boxes of "greenbar" (
Likely an LP26 or lp14, serious chainsaw (a device than changes trees to
useless pulp).
<have known some of the participants, they used to reside on ML3-6... Sorr
<if
<I digressed too far off topic...
Hahaha!!! YES! than one was infamous!
Allison
<The AMD 2900 series of chips were essentially a build-it-yourself CPU.
<The main ones were :
I have about a dozen 2901s and 2911s, fun parts. Fair amount of work
to make a system around them though.
Allison
<It is an Epson LQ-500. It has a removable set of tractors, which
<mounts on top. However, they mount on the output end. This means that
<there must be paper in the tractors that is beyond the print head,
<which means that about a sheet of paper must be wasted. Could someone
<explain to me what is the idea behind this system?
Serious answer... pulling is more reliable then pushing.
Also if that thins is like my LQ5000 and the LQ570 it can be set up in
push mode.
Allison
Actually, my favorites are the ones where the tractors are right
on the platen. No jams and no wasted paper. I once had an Epson
MX-150 that jammed something awful. I got rid of that. An example
of the former is the Okidata 120, which I used with my C-64. But
to tell you the truth, I can't stand wasted paper almost as much
as wasted hardware ;)
>Most older dot-matrix printers had tractors after the
platten/printhead.
>Some of them, like my Sanders units have 2 sets of tractors, before and
>after the platten.
>
>Yes, it does mean that you waste a sheet of paper when you finish
>printing something - you have to do an extra formfeed. On the other
hand,
>I'm quite sure it saves a lot of paper due to the reduction in the
number
>of paper jams. A lot of 'push' type tractors seem to be great at
mangling
>paper...
>
>-tony
>
>
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