Ok Megan, I'm officially Jealous.....
Nice Gear! (Especially the RK05 drives I've been looking for)... Congrats!
Jay West
-----Original Message-----
From: Steve Robertson <steverob(a)hotoffice.com>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Monday, March 29, 1999 10:15 AM
Subject: RE: Picture of my latest haul
>
>>
>> For a quick route to the picture...
>>
>> http://world.std.com/~mbg/move_step00.jpg
>>
>> Megan Gentry
>> Former RT-11 Developer
>
>
>Very nice!!!
>
>Steve Robertson -<steverob(a)hotoffice.com>
>
>
-----Original Message-----
From: Marvin <marvin(a)rain.org>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Tuesday, 30 March 1999 4:00
Subject: Re: Decwriter II
>It looks like the Paper Out signal goes into J3-6 of the keyboard assy. and
>goes into the main logic board on J2-AA/BB; the main board test point is
>TPZ17. It looks to be lo true judging by the pullup resistors.
Looks right, IIRC, the microswitch is tied to ground.
>it goes into E37 pin 12 (7474) and comes out on pin 9 as MPC8 Ready H.
Ok, that's what I needed to know, I'll have a play in that area, I think we
have a stuck
output here.
>test point is TPV20. I might add that the logic board I am looking at is
the
>M7728. I can scan in that portion of the schematic if you need it.
Ok, thanks, that would be great. I'll don't recall offhand the main board
id, I'll have a look later today.
Kindest Regards
Geoff Roberts
Periodically I swing by Surplus Property here. It's very disappointing;
there hasn't been anything exciting in a few years. Also, the University
gets first dibs at surplussed things; whatever survives is auctioned off in
big lots. So whatever interesting things ARE there tend to either disappear
again or be sold with a pallet of uninteresting things.
Having said that, I did see a good amount of Model 100s and their
accessories (disk drives, manuals) and a couple of other Tandy things
(cassette recorders). Is any of this especially rare? Some machines might
be model 102s, since I saw the 102 tecnical manual. It would be a fair
amount of effort to get everything; I might be able to convince the surplus
people to make the Tandy stuff their own lot, but I'm not optimistic about
that.
-- Derek
please see comments imbedded below.
regards,
Dick
-----Original Message-----
From: Allison J Parent <allisonp(a)world.std.com>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Monday, March 29, 1999 5:30 PM
Subject: Re: Rebirth of IMSAI
><signals? I guess it's no wonder people liked the 8085, with its silly
muxed
><data/address bus better than the 8080 . . .
>
>The 8085 had different control signals, didn't require 3 voltages, a clock
>chip, a bus control chip, was faster and allowed better memory timing.
Yes, but, moreover, it had two signals to tell you when to read and when to
write, and it had two signals telling you whether your target was memory or
I/O. The fact that it had those essentially useless (for this environment)
multi-level interrupts internally, or that it had the bizzarre (for the
time) serial I/O on chip, was relatively uninteresting in light of the
benefits of fewer power supplies, faster operation, internal clock
generation, less critical timing, and lower parts count.
><Soooo . . . the signals were named the same also, eh? pSYNC, /pWR, sMEMR,
><etc???
>
>Follow them back to the 8080. it should answer themselves. Also the 8080
>muxed status on the data bus at the early part of the cycle so the control
>signals reflect the raw 8080 status and control for the most part.
Unfortunately, all my 8080's appear on Multibus-I cards. I've NEVER owned
an S-100 8080 CPU. In fact, it wasn't until there were some single-board
computer boards on the S-100, e.g. SD Sales' SBC-100 that I even considered
using S-100 for anything.
>That's why board with 8085 and Z80 had all sorts of screwy logic to take
>their mostly decoded controls and encode them.
I certainly agree on that one! Half the logic on most of my later CPU cards
was dedicted to making the processor create the 8080-compatible signals
required for the bus. It takes less logic to implement a floppy controller,
two serial ports, a parallel port or two, and a full compliment of DRAM on
an S-100 board than it takes to make the a Z-80 or 8085 appear to the bus to
be an 8080.
>Allison
>
<be cross-referenced to the '696 standard signal names. I do hve the 8080
<data in house, but nothing tying it to the S-100 bus pinout or timing.
Someone must have the imsai or altair cpu board schematic on the net.
If not get Bursky's The s100 Bus Handbook.
<One of the reasons the S-100 required such fast memory for its relatively
<slow processors was that you had to operate relatively complex timing
<structures to create proper timing. That's a reason the standard, in my
<considered opinion, killed the S-100 rather than perpetuating it. Intel
No. The 8080 had short timing thats all. Then the later z80s wer faster
and wanted fast (relatively) memory. Bus speed was never a problem and was
good for 10mhz if terminated.
<result of course, was the chaos that results when surplus vendors e.g.
<CompuPro/Godbout (cited here because they were BIG, not because they were
Compupro was one of the closest to 696 early on!
I say this as I likely have more operational and in use S100 hardware than
most.
Allison
<For one thing, I want to ask what a few of these items are. For one thing,
<what are the three identical units on the rightmost rack? Also, what is
<the tall unit right above the green PDP in the middle rack? Also, what is
<the top unit in the short blue rack?
I'll leave this for Megan to map.
<Next question: Is there anything you can do with these that my DECMate
<can't do (besides peripherals that the DECMate doesn't have)
Not much other than the difference in expansion capability. However for
much of the PDP-8 software the 8E is the "standard" for many devices in
the IO realm. One thing does stand out... you can load core with a
program, power off and years later power up and execute that program.
Allison
<I would mention that I had 128K in each of my Systems Group systems and
<never used it under CP/M. MP/M had a mechanism for cashing in on extra
<memory, but it was awkward at best under CP/M 2.2.
<
<Needless to say, the use of a RAMdisk would speed things up, but unless
<there was an extensive amount of software for managing it, and that took u
<too much TPA, even a RAMdisk didn't help much.
Way off. Caching disks for CP/M-any (especally 2.2) is a huge performance
boost. CPM suffers from waiting on the disk and often the difference
between a slow system and a fast one is how the disks were handled. Having
run ram disks, caches, caching controllers I have studied where the
bottlenecks are and the most common is the CPU spinning in PIO or worse
waiting for the sector to come around to do PIO.
the software over head for caching is small. once you go over 128 byte
sector size yo need a host buffer to deblock it... you can read a whole
track in and deblock that. Free cache.
Allison
<>The problem in a nutshell, don't open any messages in a Microsoft E-Mail
<>program with the following title "Important Message From: {persons name}"
<
<The solution in a nutshell... run Linux, or some other more reasonable
<OS...
Actually it's the problem of word and email tightly meshed. Add to the
mix a programming language (VB macros) and you've got an open door to an
otherwise insecure system.
I run win3.1 and don't have Word so I have no problem. Though another OS
or better yet another processor would kill the bug straight out.
Allison
<signals? I guess it's no wonder people liked the 8085, with its silly muxe
<address bus better than the 8080 . . .
The 8085 had different control signals, didn't require 3 voltages, a clock
chip, a bus control chip, was faster and allowed better memory timing.
<Soooo . . . the signals were named the same also, eh? pSYNC, /pWR, sMEMR,
<etc???
Follow them back to them 8080 it should answer themselves. Also the 8080
muxed status on the data bus at the early part of the cycle so the control
signals reflect the raw 8080 status and control for the most part.
That's why board with 8085 and Z80 had all sorts of screwy logic to take
their mostly decoded controls and encode them.
Allison
If you have to align an 8"drive, the alignment diskette is pretty essential,
i.e. you can't really do well without it. The 5.25" diskettes are about as
easy to manage with software and one of the "digital alignment diskettes" if
you can get them.
Dick
-----Original Message-----
From: Joe <rigdonj(a)intellistar.net>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Sunday, March 28, 1999 6:46 PM
Subject: followup: Rinky dink hamfest
> Today I went to see a couple of the people that I meet at yesterday's
>hamfest. One of them used to service XEROX computers. He told me that he
>threw out three rooms full of old XEROX computers less than a year ago. :-(
> He gave me part of the stuff that he had left, I have to take a Truck
>(note capital) back to get the rest (estimated at two cubic yards but no
>complete machines). So far I've found lots of docs and 8" flopppy disks
>for the 820 and 16/8. The 16/8 looks pretty interesting, it ran CPM,
>CPM-86 and MS-DOS. Does anyone have one of these? What's your opinion of
>them?
>
> He has a floppy disk drive control box to manual operate 3.5", 5.25" and
>8" drives during alignment. Anyone have an idea of what one of these is
>worth with the alignment disks and manuals?
>
> Alos found a Lisa mouse to go with the Lisa that I got yesterday.
>
> Joe
>
