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Vintage Computers Any vintage computer systems, calculators, video games etc., but with an emphasis on 1980s and earlier equipment.

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Old 6th Feb 2016, 12:37 pm   #61
G6Tanuki
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Default Re: Strangest computer you have had?

GPIB/IEE488/HP-IB was used on quite a lot of early mini/microcomputers: I remember wire-wrapping a GPIB-to-RS232 interface for use with a Commodore PET (which also used GPIB as its printer / plotter interface: I wish I'd kept the HP-IB equipped H-P 7475A plotter we used ... ).
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Old 7th Feb 2016, 3:02 am   #62
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Default Re: Strangest computer you have had?

Wasn't Commodore's version of IEE488 serial, as opposed to parallel as found on HP kit? Still, I suppose there's only a couple of shift registers in it either way ...
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Old 7th Feb 2016, 10:57 am   #63
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Default Re: Strangest computer you have had?

Quote:
Are the opamps discrete?...Germanium or silicon?
Discrete, mostly Ge. I haven't got the schematics to hand but the computation amps have something like a 5-stage AC-coupled main amp, in tandem with a 4-stage chopper-stabilised DC amp. I forget the specs, it's good to a few hundred kHz and has respectable O/L gain and offset for its age.
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Old 7th Feb 2016, 11:37 am   #64
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Default Re: Strangest computer you have had?

Parallel.
I used to run HP GPIB kit on a PET
Ian
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Old 7th Feb 2016, 9:59 pm   #65
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Default Re: Strangest computer you have had?

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Originally Posted by julie_m View Post
Wasn't Commodore's version of IEE488 serial, as opposed to parallel as found on HP kit? Still, I suppose there's only a couple of shift registers in it either way ...
Nope - it was fully-parallel, though with a number of odd timing quirks [so sometimes when waiting for a control-line transition you needed to 'go round twice' before trusting that it'd truly settled].
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Old 8th Feb 2016, 7:59 am   #66
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Default Re: Strangest computer you have had?

I think you're both right. As far as I remember, the early Commodore 'professional' machines like the PET used a parallel bus, but the later lower-cost domestic ones like the Commodore 64 used a serial implementation of basically the same bus. The best-known example of a peripheral was the 1541 disc drive. They were famous for being dismally slow because of the serial interface, but because they had an on-board CPU, enterprising developers were able to come up with ways of speeding it up.

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Old 8th Feb 2016, 1:36 pm   #67
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Default Re: Strangest computer you have had?

My first (and probably most unusual) computer:

https://en.m.wikipedia.org/wiki/Texa...ments_TI-99/4A

On the upside, I learned BASIC on it and it whetted my appetite for computing. It was, in many ways, a deeply flawed machine though and I became quickly frustrated with the very low speed of the BASIC interpreter and difficulty in utilising the power of the 16 bit processor, which should have made this one of the fastest machines of its day. Sadly it was a botch job by TI, envisioned as a platform for selling expensive software cartridges (presumably to keep TIs fabrication plants busy) whilst actively suppressing the development of third party software.
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Old 8th Feb 2016, 3:38 pm   #68
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Default Re: Strangest computer you have had?

HI,
I was just going to post about having used briefly a TI-99/4A but PSValves got ahead of me. I never had the option rack mounted floppy drives and expansion ! If only the basic machine had a few more options built into it rather that having to buy additional bits.
regardsPeter B
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Old 8th Feb 2016, 5:53 pm   #69
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Default Re: Strangest computer you have had?

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Originally Posted by Lucien Nunes View Post
Does this count?

EAL TR48, discrete transistor 10V analogue computer with 48 op-amps, c. 1962
I think that one gets the gold medal.
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Old 8th Feb 2016, 6:13 pm   #70
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Default Re: Strangest computer you have had?

When I was at school, we had a brief maths session on mechanical calculators (Burroughs type), followed by a demonstration of the teacher's pride and joy - a binary adder comprising two rows of toggle switches and a corresponding row of indicator lamps. This, we were told, was a digital computer.
Although I never built it, a book I owned included plans for a similar, somewhat more sophisticated device based on uniselectors. One literally dialled-in the input via a telephone dial.
Neither, I suppose, really counted as programmable, but they were certainly educational.
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Old 11th Feb 2016, 3:36 pm   #71
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Cool Re: Strangest computer you have had?

Hello People,

I think what you are looking for is a proper computer. Check out my GEC 4070 in it's original location before I rescued it !!
It has blinking lights and everything, only slight issue is power - +5v @ approx. 70A per box + additional supplies

Enjoy,
Alan.
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Old 11th Feb 2016, 4:19 pm   #72
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Default Re: Strangest computer you have had?

If you want some good photos of old computer kit see the link.
I repaired a very few of these at this site, never owned them but came to know one or two very well.
http://tardis.dl.ac.uk/computing_history/archive.html

Frank
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Old 11th Feb 2016, 5:14 pm   #73
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Default Re: Strangest computer you have had?

Quote:
Originally Posted by BassoonBloke View Post
I think what you are looking for is a proper computer. Check out my GEC 4070...
I must say I'm envious, as I would love to have a memento of the days when I used to program "proper" computers (and to have the space in which to house it). I have to say, though, that to me a "proper" computer filled a room the size of a football pitch, given that I started my working life with the likes of IBM 370 mainframes, where a hard disc drive alone (with a capacity of a few megabytes) was about the size of a large laundrette washing machine.
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Old 11th Feb 2016, 5:37 pm   #74
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Default Re: Strangest computer you have had?

See the link in post #72, IBM 370 photos in those among many others.
Large washing machine size disk drives, either have the "pick signal" enabled (CDC drives)or don't power them up all at once.
Frank
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Old 11th Feb 2016, 8:33 pm   #75
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Default Re: Strangest computer you have had?

Quote:
Originally Posted by BassoonBloke View Post
I think what you are looking for is a proper computer. Check out my GEC 4070 in it's original location before I rescued it !!
*envy*

I was closely involved with GEC 40xx/41xx hardware a while back: a fistful of GEC4160 packet-switches which formed the emergent JANET X.25 network, and a number of 4090A that were used as general-purpose computers and also served as HASP workstations to send/receive batch-jobs to the likes of the UMRCC CDC7600 and a number of IBM mainframes at the likes of RAL, Daresbury and ULCC.

We also had a GEC2050 which was never reliable, and got replaced by a CTL Modular/1 that was rather more impressive because it could drive a 160-column lineprinter at 1600 lines/minute nonstop.
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Old 11th Feb 2016, 9:08 pm   #76
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Default Re: Strangest computer you have had?

Yes, I did have a little nostalgic stroll among the images of both the 370 and the 1800 which was next down - and the first computer I wrote programs for (in FORTRAN IV and assembly language) during my sixth-form days at school.
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Old 12th Feb 2016, 6:47 pm   #77
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Ah... the 370, down a teletype link to Cambridge when I was at school (early 1970's). Who remebers CECIL?

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Old 12th Feb 2016, 7:49 pm   #78
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Default Re: Strangest computer you have had?

CECIL or CESIL?
(I suspect the latter in this context).
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Old 12th Feb 2016, 9:38 pm   #79
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Correct - Computer Education in Schools Instruction Language.
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Old 12th Feb 2016, 9:48 pm   #80
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Well it was a while ago! CESIL
 
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