core memory

On a sunny day (Sat, 05 Dec 2009 20:10:52 -0500) it happened PeterD wrote in :

I have a DVD+R hanging on the wall, shiny side front, looks nice, stores more data. Do not remember what is on it.

Reply to
Jan Panteltje
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Yep ! Seeberg or was it Seaberg made them. Bloody great big block !

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                     Baron.
Reply to
Baron

Many a poor woman's eyesight in the third world ruined making those, I'll be bound.

Sylvia.

Reply to
Sylvia Else

I remember using those back in the early 70s. Made in Ireland.... 16K and

32K, but I forget the width. It was for a PDP 'clone' that was designed by some Ex Uni boffins from Sussex. Controller board was a nightmare ( as I remember), full of 121 and 123 monostables :( Was used as a CNC controller ( one of the first) on Herbert Machine Tools in Coventry. The machine had a 64x24 bit diode microprogram matrix ( replaced by otproms)and could do x+y+z in one instruction (software, that is), in a few microsteps...ALU had about 100+ logic chips.... Ahh the good old days.
Reply to
TTman

The first 11, the PDP-11/20, was an asynchronous hairball, like the PDP-8s. It was full of RCs, delay lines, and bizarre logic paths, and was all MSI TTL, over 500 packages on two boards, no microcode. There was a short assembly program that used the paper tape reader to cause a metastability that totally locked up the CPU. Early 70s was about when people started getting religion about synchronous logic design.

Actually, I don't miss them all that much.

John

Reply to
John Larkin

Do you think that doing close work ruins vision? What about sewing? Or reading?

John

Reply to
John Larkin

I recall seeing the last one (or two) as examples. Semis had just taken over. I assume somebody who later owned a guide dog got to thread them...

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Dirk

http://www.transcendence.me.uk/ - Transcendence UK
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Reply to
Dirk Bruere at NeoPax

TTman... as in Audi?

John

Reply to
John Larkin

I still have a box full of memory boards for the VAX, made by National Semiconductor.

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Reply to
Michael A. Terrell

There are still tens of thousands of VAXen in use. And there's some excellent VAX/x86 emulator software.

John

Reply to
John Larkin

Do you have more details about these clones ?

The only PDP-11 clones that I am aware of are the Russian SM4 (PDP-11/34 clone) and the E60 (LSI-11/03 clone).

Reply to
Paul Keinanen

Haha .... 450 bhp Supra MkIV.... Actually TomTom, cos I used to repair them. Absolute crock of shit design...

12V source from the Cigar lighter...with 5V switcher..... with the sense wire running down the cable to the power socket in the TT. So far, so good.... then the cable gets a break and the switcher decides it needs to up the voltage to 'close the loop'Up to 12V that is.... Inside the TT, the boards are ful of 6V MAX chips, so they all blow. Marvellous!
Reply to
TTman

It probably wasn't a clone in the true sense of the word. I don't actually know.But it was very similar in architecture. Probably not.... The whole thing was in a 19" rack. We designed /made most of it in house. The PSU was bought in. 5V @ 20 A + , +/- 15V @ 5 amps.Boards were all A4 size, with a backplane motherboard. As I remember: ALU board Register board I/O board Core stack ( 3/4 boards in all, all bolted together, inc, cores) TTY interface DC Servo control boards with encoder feedback (14 bits) + dither control for anti stiction Front panel with 'Boot' switches Boot code was entered in octal, using 8 data switches and 10? address switches, and a 'load' switch. Data and address leds, + run led ? Simplest boot loader was a paper tape input loader, that then loaded the main program. Company naame was Micro Computer Systems, in Woking, Surrey. circa 1970 -

1977
Reply to
TTman

Another benefit I did for GM... sense wire breaks, regulator shuts down (I sensed if there was current in that wire). ...Jim Thompson

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| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
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Reply to
Jim Thompson

SNIP

More info, taken from The Hansard, 1972............

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For example, Alfred Herbert Ltd. has produced a superb development. It is not a machine but a computerised development called the Batchmatic, which makes it possible to have multiple control of batches of machines. It has not been seen before in British industry. It is the high point of the second industrial revolution. But these tremendous machines, which no doubt competitors in Western Germany and elsewhere will copy and produce, will not go into production simply because firms are doubtful. They are hesitant because there is a lack of confidence. Firms are unwilling to place orders for these machines.

Reply to
TTman

Yikes. For, say, the last 12,000 years it's been standard practice to add a local resistor to close the loop when a remote sense connection opens.

I got an Audi because it's the only 4WD vehicle that doesn't look or drive like a 4WD vehicle.

ftp://jjlarkin.lmi.net/A3a.jpg

This was used, purchased at absurd expense by a guy who had six boy-toy cars in 2008, back when he had a job.

John

Reply to
John Larkin

There were at least two pre-Mentec PDP-11 clones made in the USA. One was commercial and unauthorized, one aerospace and apparently blessed by DEC. I can't recall the names.

John

Reply to
John Larkin

The last one looks like the one I was just looking for. I took it out of a Linc 8 I believe.I still have the front panel. When I first started working, I was at DEC in 1969. I seem to recall seeing the women making memories. A real programmer could really toggle those front panel switches fast.

greg

Reply to
GregS

Almost square B-H loops.

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Reply to
Fred Abse

Ampex made some very small core memories in the '70s. 32K in the size of a paperback book. You needed a magnifier to see that the cores were toroids. God knows how they threaded three wires through each one.

I must have dumped dozens. Wish I'd kept one, now. The only thing I saved was a few of the mumetal screening plates.

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"Electricity is of two kinds, positive and negative. The difference
is, I presume, that one comes a little more expensive, but is more
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Reply to
Fred Abse

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