Billy Pettit real disappointment

Roger Holmes roger.holmes at microspot.co.uk
Thu Jun 28 06:01:16 CDT 2007


On 28 Jun, 2007, at 04:59, cctalk-request at classiccmp.org wrote:

> Message: 3
> Date: Wed, 27 Jun 2007 15:23:32 -0700
> From: "Billy Pettit" <Billy.Pettit at wdc.com>
> Subject: What are the really unusual or weird computers?
> To: <cctalk at classiccmp.org>
> Message-ID:
> 	<5BC121186B788C48A0EE35A16FD0D34D29C6E2 at wdscexbe01.sc.wdc.com>
> Content-Type: text/plain;	charset="us-ascii"
>
> This thread has been a real disappointment.  Almost all of the  
> responses
> have been about computers using standard microprocessors - off the  
> shelf
> components.  Yes a few had non-vanilla flavored OS's, or idiotic I/O
> schemes.  A few were even painted different colors from PC Beige.

Then you are not reading all the replies.



> But nobody got into the really weird internals that have made the  
> industry
> so fascinating.  Go back to the real early days, like the Atlas,  
> that let
> you build your instruction set from scratch using micro-code.   
> Nobody seemed
> to remember that most of the late 50's and early 60's used 40 bits  
> as a
> standard.

MOST?????    STANDARD?????    Rubbish!     IBM 7094 - 36 bits. ICT  
1301 - 48 bits. CDC 6600/7600 60 (or was it 64?) bits. CDC SC17 (not  
sure exact era) - 16 bits. Elliott 903/920B/905/920C/920ATC - 18  
bits. Many of the BCD machines used 4 bit words I believe. Mid 60s  
ICL 1900 - 24 bits. What used 40 bits?



> What about the MicroData machines with a build your own
> instructions on the fly?


Tell us more please. Microcoded or 'Extra code' ?



> And then there were the ultra-strange like the G-15 - 29 bit word  
> size, all
> instructions were modified moves through arithmetic logic or I/O  
> devices.
> The I/O devices were actually part of the internal logic - no  
> channels.

Actual physical memory, access my DMA from the device or just memory  
mapped I/O ?


> Burroughs had some fascinating ideas on virtual memory in the 5500  
> series.
> Seymour Cray lived weird and unusual in most of his designs.   
> Several people
> have developed machines to run high level languages in native mode:  
> ADA at
> Rational, APL on the Star 100, LISP, COBOL, etc.
>
>
>
> There's not much unusual about putting some glue logic around a $3  
> micro
> chip.  We've all done it.  How about the truly weird machines?   
> Doesn't
> anyone remember when logic didn't come in million transistor packages?

Remember? I am restoring/maintaining an ICT 1301 which has individual  
Germanium transistors, wire-OR, four and gates to a PCB, one flip- 
flop one a PCB, a clock derived from the timing track of the last  
addressed drum store, a core store unit weighing half a ton an stores  
just 2000 x 48 bit words (plus 2000 x 2 parity bits). Its got Ampex  
TM4 mag tape drives (not industry standard 7 or 9 track, these are  
ten track units with hubs the same design as professional audio tapes  
and the 2 and 3 inch wide video tapes once used by TV broadcasters).  
Its got readers and punches for 80 column cards and 5, (6 or 7?) and  
8 track paper tape, its got a 600 line per minute barrel printer with  
120 print positions. The mag tape transfers are done by DMA but the  
rest and unbuffered peripherals, if you want to print a line on the  
printer, you check to see what character is in line with the hammers,  
see if you have any of them in your line, and fire those print  
hammers which match, then wait until the print barrel moves on then  
repeat until you have printed the whole line. Then you look up where  
the paper advance mechanism currently is and select the next sprag  
and release current one. If you want to page feed, release all the  
sprags and count the 60 lines as they go past.

To punch a card, in software, turn the 3 phase contactor on to start  
the motor, wait until its at the correct speed, activate the picker  
knives to start the card in motion (sideways), look to see which if  
any of your 80 columns need a hole in the first (10) row, wait until  
that row is under the punch bail, fire those interposers, repeat for  
the 11 row, then the 0,1,2,3,4,5,6,7,8 and 9 rows. Then feed the next  
card and at the same time get ready to verify the card you just  
punched. Wait until the 10 row is under the check reading wire  
brushes, read them in and see if they match, repeat for all the other  
eleven rows, if anything fails to verify, send the card (and the  
following one) to the reject hopper, stop the punch and inform the  
operator.


> Come on people: there were computers long before there were  
> microcomputers.

And some of them still work and have 'design council' award winning  
control consoles 4 feet wide and 2 and a bit feet tall, consume 13KVA  
three phase and weigh about 5 tons.

> And many of them were wonderfully different and creative.

Indeed. And some of them almost make you cry because so much more  
could have been done with the same amount of electonics. My machine  
has been modified to implement an index instruction. Previously all  
indexing and indirection had to be done by program modification, and  
even now subroutine return is done that way (see my previous e-mail).  
I have one machine in 'conserved' state, unmolested, unrepaired non- 
runner, and one with extra tweeks and darn right mass rewiring which  
runs and I can't stop thinking about how it could be improved, yet  
somehow manage to stop myself doing so. There are so many gaps in the  
instruction code and spare bits in the instructions etc. The only  
modification I am working on plugs into an extension port lashed up  
by a previous owner. This is to capture the data from the machine  
onto modern media. May replace with an RS232 interface later to drive  
a teletype and/or pen plotter, and/or a parallel inteface for a  
Friden Flexowriter.

Anyone got a spare plug for the i/o port of the Flexowriter, or for  
an IBM keypunch (model 836) or spare patch leads for the patch panel  
(4mm with a ball in them).

Anyone got a spare Ellliott paper tape reader, preferably 1000  
characters per second but a 300cps unit would do. My machine  
originally had two readers but somehow I only ended up with one of them.

Anyone got any spare 'ICL Standard Interface' peripherals I could  
plug into the vacant port on the machine?

Anyone in the UK want an Elliott surface grinder which leaks  
hydraulic fluid or want an Alba shaper (a planing machine for steel,  
a brutal thing, takes out about 1/16 - 1/8 at every stroke, comes off  
bright red). Or a really old pillar drill, large capacity, looks  
prehistoric. All three phase of course.

Again in the UK, anyone got any punched card trays, the steel type,  
preferably with the racks too, but the trays only would be a help.

Willing to pay (reasonable) price for any of the above.

Roger Holmes.
Classic computer collector, classic car collector, machine tool  
collector/user (for the prior mentioned hobbies), and for a job,  
programmer of CAD and graphic software and printer/plotter drivers  
for Apple computers.

>
>
>
> Billy
>
>




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