Yes, I believe I have one. I can't lay hands on the manual right away, but
maybe by 10:00 pm (it's about 6:20 pm now) I'll have it in hand.
IIRC, the index pulse is generated from a hall sensor which looks at the
spindle. So long as you get only one index pulse per revolution, and so
long as those revolutions are close to the rated speed (60 Hz) they should
satisfy nearly any controller's needs and allow the drive to be low-level
formatted.
Dick
Dick
-----Original Message-----
From: Tony Duell <ard(a)p850ug1.demon.co.uk>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Tuesday, October 19, 1999 3:33 PM
Subject: Fixing an ST412?
>Short question : Does anyone have a Shugart ST412 service manual?
>
>Long Question : As some people here know, I'm slowly rebuilding a DEC
>rainbow. And today it got to the point where it was worth trying to boot
>it. It booted fine from the RX50 floppy drive, but not from the RD51 (aka
>ST412) winchester.
>
>A little bit of probinf with a LogicDart revealed that the drive was
>producing no index pulses, although it was spinning. There are schematics
>for the older version in the IBM O&A techref, and using these as a
>reference, I quickly found that the index sensor itself was producing no
>output.
>
>Off with the logic board, and I found that the index sensor was loose in
>the clamp, and about 1/4" from the arms on the motor that trigger it.
>I adjusted it closer, tightened it up, put it all together, and it seems
>fine. The 'Bow boots from the winchester and seems to be able to run
>programs, etc.
>
>What I want to know is is there a proper procedure for adjusting this
>sensor? Is there a particular value quoted for the gap between the sensor
>and the arms?
>
>As I said, it's OK now, but I might as well do it right.
>
>-tony
>
> ------------------------------
>
> Date: Mon, 18 Oct 1999 14:41:47 -0400
"Bill Sudbrink" <bill(a)chipware.com> said:
> I've hunted around on the web to no avail...
> Can anybody give me the specs on these?
According to my Tandon OEM Operating and Service Manual
for the TM100-1 and TM100-2:
Tracks per inch 48 TPI both drives
Tracks per drive TM100-1 40 tracks, TM100-2 80 tracks
Disk Rotational Speed 300 RPM +/- 1.5%
Motor Start Time 250 milliseconds
Motor Stop Time 150 milliseconds
Seek Time,track to track 5 milliseconds
Head Settling Time 15 milliseconds
Ave Track Access Time 75 milliseconds
Typ. Recording Modes FM,MFM,MMFM
Data Transfer Rate 250,000 bits per second
Unformated Cap. TM100-1 250Kb per disk, TM100-2 500Kb per disk
Bill,
Let me know if you need a copy of this. Thanks again for the C4P boot
disks. The C4P-MF is coming along nicely. The power supply checks out
and I'm pulling every socketed chip and reseating it during the
cleaning.
So far, I've found 5 chips with pins broken down inside the sockets.
Fortunately, I was able to remove the pins from the sockets.
Now I just need to pick-up some replacement 8T26 bus driver/receivers
and then check all of those 2114s on the two 527 Ram boards and I'll
be ready to fire this thing up. :)
--Doug
====================================================
Doug Coward dcoward(a)pressstart.com (work)
Sr. Software Eng. mranalog(a)home.com (home)
Press Start Inc. http://www.pressstart.com
Sunnyvale,CA
Curator
Analog Computer Museum and History Center
http://www.best.com/~dcoward/analog
====================================================
Yes, I agree that you'd want to approach things differently than you do your
work. Perhaps an attempt at wire-wrapping a processor with "period"
components? I mentioned that I did that once. It wasn't until I tried that
that I came to appreciate how thrifty the processor really is when compared
with others.
Of course, you may not find that to be fun either.
Building an S-100-based 8080 core out of TTL offers an added benefit in that
the 8080 timing logic suits the S-100 bus signal layout and timing. When
you're done, there's a wealth of software you can play with. I would say
you ought to be able to build a processor core twice as fast as the original
8080A, jet using only a single supply.
It's not likely I'll do that, but it is a tempting notion.
Dick
-----Original Message-----
From: daniel <daniel(a)internet.look.ca>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Wednesday, October 20, 1999 11:06 AM
Subject: Re: OT: how big would it be?
>
>-----Original Message-----
>From: Richard Erlacher <edick(a)idcomm.com>
>To: Discussion re-collecting of classic computers
><classiccmp(a)u.washington.edu>
>Date: Wednesday, October 20, 1999 12:33 PM
>Subject: Re: OT: how big would it be?
>
>
>>Why not explore this problem from the standpoint of an FPGA? When you
>>finish you'd still have the flexibility of a hand-built device, yet what
>you
>>learned in the process would potentially be of actual use?
>>
>
>(if this was directed at me)
>
>I have to design that kind of crap now, every day. I just got *into*
>transistor computers and find it quite interesting to see what games I can
>play with old RTL type stuff.
>
>>Why squander your cash and intellectual resources on creating something
the
>>folks in the '70's electronics industry were striving to avoid when you
>>could have the same mental exercise in a productive form that made the
>>design and implementation of your architecture the core of your effort
>>rather than issues which are no longer relevant, like power consumption,
>>packaging, and finding the appropriate materials from which to build your
>>device? Signal routing is the one issue which persists from that era of
>>yesteryear when a CPU lived in multiple racks, but it's handled, at least
>>superficially, by the development software. Sharing flipflop packages or
>>gates between two circuits on a backplane with 50 cards of logic in it is
>no
>>easy matter. What's more, the propagation delays will slow your circuit
>>down to cycles in multiple microseconds, while correcting the associated
>>routing errors will take multiple days for each one. While it's not
>>perfect, the FPGA approach allows you to have these experiences with a
>>"virtual" closet-sized backplane with similarly "virtual" cards (modules)
>of
>>logic which you can design hierarchically and based on your needs, not on
>>what the local parts vendor happens to have.
>>
>
>I design high speed logic (some basic config cpu cores) now using Xilinx
and
>even some AMD chips (yes, I use to use the MACH stuff) all with various
RISC
>chips. I don't want to come home at night and *continue* the same type of
>design work (or code). I find it more entertaining to work on an 8/S , not
>drop one in a chip [though that might be interesting]. I try to spend my
>time on the old systems which is what taught me back in '79 so much about
>the new ones.
>
>This unit will be nothing more than a conversation piece (in my office,
>hopefully doing some small task) and I hope to have some fun with quick and
>dirty logic.
>
>If my PDP-8/S wasn't so *mint* in the rack I'd rip it out, drop it in a 8/E
>table top case and drag it into the office to do something fun.
>
>john
>
>
>>Dick
>>
>>-----Original Message-----
>>From: Mike Cheponis <mac(a)Wireless.Com>
>>To: Discussion re-collecting of classic computers
>><classiccmp(a)u.washington.edu>
>>Date: Wednesday, October 20, 1999 9:35 AM
>>Subject: Re: OT: how big would it be?
>>
>>
>>>> > Say someone were to home-build a CPU from scratch using only
>individual
>>>> > components, no ICs only modern discrete(?) components. How big would
>>the
>>>> > CPU be? For comparison lets say it would be an 8080 clone. Any
>>guesses?
>>>
>>>It seems to me the Right Answer is to approximate the number of
>transistors
>>>required. How many transistors did an 8080 have? (Do remember, however,
>>>that the transistor count is actually less than you'd need with discrete
>>>transistors, because the on-chip transistors can have multpile emitters
or
>>>gates or whatever in the same device.)
>>>
>>>As for how "big" it would be (that is, its size), modern discrete
>>transistors
>>>are available in tiny SOT-23 or even tinier packages. Resistors are
>>>available in 0402 and maybe smaller. Line widths on PC boards can
perhaps
>>>be as small as .002 inches, and they can be many layers, a dozen or more.
>>>
>>>So, in order to compute the size, I think you'd need to make two
>estimates:
>>>
>>>1) The number of transistors per cubic inch (or cm if you like those
>units)
>>>
>>>2) The number of transistors required.
>>>
>>>This assumes some packaging/connector allowance is taken into account to
>>>estimate the number of transistors per cubic whatever.
>>>
>>>------
>>>
>>>IMHO, if you're going to build something from transistors, why not build
>>>something that was originally built with transistors? For example, the
>>>IBM 1620, 1130, 1401, etc. Or if you really want to get funky, try
>>something
>>>like transistorizing a tube machine, like ENIAC or JOHNNIAC or Bendix
>G-15.
>>>-That- could be entertaining...
>>>
>>>-Mike Cheponis
>>>
>>
>
-----Original Message-----
From: allisonp(a)world.std.com <allisonp(a)world.std.com>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Wednesday, October 20, 1999 2:09 PM
Subject: Re: OT: how big would it be?
>On Wed, 20 Oct 1999, daniel wrote:
>
>> Allison: You worked on transistor 8s? How did they impliment the 20mA
>> current loop. I posted a message a while back about how it *was* set up
in
>> this cpu. The schematics of a PT08 show nothing other than one TTY line
>> right into the receiver board.
>
>It was a transistor level converter from logic levels to 20ma. the
>circuit for wich is fairly simple. It was the serial/deserial hardware
>that ate a few boards. As in the case of the most 8's the tx/rx data was
>directly to the Accumulator. There were designs that would stall the
>machine while the bits were serialized/deserialized and written one by one
>to Acc. Saved registers but the cpu was stopped for about 1/10th second.
>
>Allison
>
I know that but do you know the original circuit used between the teletype
and the receiver board? I have a simple circuit running now. The current
backplane shows R107 (inverters)
john
>
>Ok, so who would be interested in creating a repository of "generic" gate
>designs?
>
>Are the flip chip cards copyrighted? (Somehow I doubt Compaq would come
>after us if we started building them :-)
The PC artwork might be copyrighted, but the protection on the circuit
design would be a patent. And the patents have (in the case of
the "classic" technology being discussed) almost certainly expired
by now.
>Are they the correct technology? I like 'em because you can get to parts of
>the circuit easily, but it is more compact to put everything on just a few
>boards.
>
>Have we ruled out using SMT technology? We could easily build a 16 bit
>register on a single flip chip sized card with SMT stuff.
I, personally, don't think that surface mount is the way to go. I'd prefer
to see all the transistors in TO-3 cans, though of course real transistors
on flip chips often were TO-92's, and these offer a definite cost and
density advantage (as does SMT, but I think that's a bit too far!)
Tim.
-----Original Message-----
From: Mike Cheponis <mac(a)Wireless.Com>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Wednesday, October 20, 1999 11:28 AM
Subject: Re: OT: how big would it be?
>> > Say someone were to home-build a CPU from scratch using only individual
>> > components, no ICs only modern discrete(?) components. How big would
the
>> > CPU be? For comparison lets say it would be an 8080 clone. Any
guesses?
>
>It seems to me the Right Answer is to approximate the number of transistors
>required. How many transistors did an 8080 have? (Do remember, however,
>that the transistor count is actually less than you'd need with discrete
>transistors, because the on-chip transistors can have multpile emitters or
>gates or whatever in the same device.)
>
>As for how "big" it would be (that is, its size), modern discrete
transistors
>are available in tiny SOT-23 or even tinier packages. Resistors are
>available in 0402 and maybe smaller. Line widths on PC boards can perhaps
>be as small as .002 inches, and they can be many layers, a dozen or more.
>
>So, in order to compute the size, I think you'd need to make two estimates:
>
>1) The number of transistors per cubic inch (or cm if you like those units)
>
>2) The number of transistors required.
>
>This assumes some packaging/connector allowance is taken into account to
>estimate the number of transistors per cubic whatever.
>
>------
>
>IMHO, if you're going to build something from transistors, why not build
>something that was originally built with transistors? For example, the
>IBM 1620, 1130, 1401, etc. Or if you really want to get funky, try
something
>like transistorizing a tube machine, like ENIAC or JOHNNIAC or Bendix G-15.
>-That- could be entertaining...
>
That might be an interesting thing to do but I have no information on any of
those cpus. Really, have to sit down and find "the ulimate" cpu to
transistorize. 4004 seems reasonable (from the new stuff), I would not want
to try and build a staight 8 from scratch. I work heavily now with xilinx
and embedded applications (pic and scienix).
Allison: You worked on transistor 8s? How did they impliment the 20mA
current loop. I posted a message a while back about how it *was* set up in
this cpu. The schematics of a PT08 show nothing other than one TTY line
right into the receiver board.
>-Mike Cheponis
>
>If my PDP-8/S wasn't so *mint* in the rack I'd rip it out, drop it in a 8/E
>table top case and drag it into the office to do something fun.
Will an 8/S fit in an 8/E table-top case? I don't have an 8/S myself,
but in the pictures I've seen it looks to be a bit taller than the 8/E's
6 SU's (10.5 inches).
--
Tim Shoppa Email: shoppa(a)trailing-edge.com
Trailing Edge Technology WWW: http://www.trailing-edge.com/
7328 Bradley Blvd Voice: 301-767-5917
Bethesda, MD, USA 20817 Fax: 301-767-5927
A PDP-8 or a PDP-8/S. Both were made with transistors alone.
PDP-8/S (filing cabinet)
BTW: I am building an Intel 4004 or possible an 8008 with flip chip modules.
Will tell you when I start it.
john
-----Original Message-----
From: Joe <rigdonj(a)intellistar.net>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Wednesday, October 20, 1999 2:12 AM
Subject: Re: OT: how big would it be?
>I'd say about the size of a HP 9100. But it isn't a 8080 clone.
>
> Joe
>
>At 01:40 AM 10/20/99 -0400, you wrote:
>>I know its off-topic but i figured that since most of the poeple on this
>>list work or have worked on the really big stuff you'd know better than
>>most others.
>>
>>Say someone were to home-build a CPU from scratch using only individual
>>components, no ICs only modern descrete(?) components. How big would the
>>CPU be? For comparison lets say it would be an 8080 clone. Any guesses?
>>
>>pbboy
>>
>
Do you have a list of bit-serial processors [without much integration]?
I would be interested in finding more.......... hopefully.
john
-----Original Message-----
From: CLASSICCMP(a)trailing-edge.com <CLASSICCMP(a)trailing-edge.com>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Wednesday, October 20, 1999 12:57 PM
Subject: Re: OT: how big would it be?
>>Well . . . if you mean really discrete, i.e. no TTL SSI/MSI stuff, you
need
>>to recall that a single flip-flop was resistors, capacitors and a handful
of
>>transistors.
>>...
>>There, methinks you'd be talking about a board as big as your dining room
>>table, with miles of wire, and potentially millions of errors to correct.
>
>No, it doesn't have to be as big as a dining room table. Like I said,
>I own several examples of bit-serial processors implemented using
>discrete components - for example, my Monroe programmable calculator -
>which pack everything onto a few square feet of printed circuit board,
>and not incredibly dense PCB's at that.
>
>There are other examples of bit-serial processors in my collection -
>for instance, the HP 9100A - where there is some, but not much, integration
>used. The big PCB in the 9100A is the ROM, while the processor itself
>resides on a daughtercard!
>
>--
> Tim Shoppa Email: shoppa(a)trailing-edge.com
> Trailing Edge Technology WWW: http://www.trailing-edge.com/
> 7328 Bradley Blvd Voice: 301-767-5917
> Bethesda, MD, USA 20817 Fax: 301-767-5927
>
