Test Equipment Anonymous (TEA) : Discussion and Group Therapy Thread

[Zenith]

Spend much time sitting at a keypunch writing up test cases for MECL 10K array boards that were going into an interface tester for the under development 3081. The punched cards were inputted to an IBM 1130 computer. Results printed out on a 1403 chain printer. As I recall the 1130 had a massive 1MEG removable hard drive.

Aaagh! Don't do that. I was trying so hard to forget stacks of bloody Hollerith cards, or rather bloody stacks of bloody Hollerith cards held together with a bloody elastic band. The elastic band was possessed of a malevolent intelligence. If you went to the extra trouble of numbering the cards for easy ordering, the band would never break, but it was so much extra work. If it broke it would be at the least convenient time. Either just in time to miss a run, or most of the cards would end up in a muddy puddle, which seemed put there for the precise purpose of spoiling them.

[tggzzz]

Spend much time sitting at a keypunch writing up test cases for MECL 10K array boards that were going into an interface tester for the under development 3081. The punched cards were inputted to an IBM 1130 computer. Results printed out on a 1403 chain printer. As I recall the 1130 had a massive 1MEG removable hard drive.

Aaagh! Don't do that. I was trying so hard to forget stacks of bloody Hollerith cards, or rather bloody stacks of bloody Hollerith cards held together with a bloody elastic band. The elastic band was possessed of a malevolent intelligence. If you went to the extra trouble of numbering the cards for easy ordering, the band would never break, but it was so much extra work. If it broke it would be at the least convenient time. Either just in time to miss a run, or most of the cards would end up in a muddy puddle, which seemed put there for the precise purpose of spoiling them.

I never used cards, only 5 and 8 channel paper tape.

I thought the standard trick with punched cards was to mark a big X on the stack's top edge, which would simplify restoring their order.

[MED6753]

Spend much time sitting at a keypunch writing up test cases for MECL 10K array boards that were going into an interface tester for the under development 3081. The punched cards were inputted to an IBM 1130 computer. Results printed out on a 1403 chain printer. As I recall the 1130 had a massive 1MEG removable hard drive.

Aaagh! Don't do that. I was trying so hard to forget stacks of bloody Hollerith cards, or rather bloody stacks of bloody Hollerith cards held together with a bloody elastic band. The elastic band was possessed of a malevolent intelligence. If you went to the extra trouble of numbering the cards for easy ordering, the band would never break, but it was so much extra work. If it broke it would be at the least convenient time. Either just in time to miss a run, or most of the cards would end up in a muddy puddle, which seemed put there for the precise purpose of spoiling them.

I never used cards, only 5 and 8 channel paper tape.

I thought the standard trick with punched cards was to mark a big X on the stack's top edge, which would simplify restoring their order.

Used paper tape too on another project that used an IBM System/7 as a driver for the tools.. Loading code on that machine was via standard cassette.

Damn I'm freaking old.


.

[tautech]

Just as an interest, what sorta card feed rate /s was achievable ?
How might that convert to a data baud rate ?

[tggzzz]

My recollection for paper tape being read from a spool/roll was 1000cps. The tape spat out horizontally several feet, and was captured in a large bucket. [1]

The sprocket holes were not used to pull the tape, and would probably have ripped the paper. Pulling was via a roller which clamped down across the complete paper width; clamping/releasing provided very fast start/stop. The sprocket holes acted as a clock signal, so the tape speed was not critical.

There are many yootoob vids of a DEC PC05 "high speed" reader fanfold (!) paper tape at 300cps. Certainly much slower than the ones I used.

Punching/copying was much slower. I had to use an ASR33, so 10cps.

IIRC colossus was 5000cps, but continuous loop no start/stop.

[1] Edit: correct, 2.5m/s https://moca.ncl.ac.uk/iomedia/pt2.htm

[Zenith]

Card feed rate would depend on the model of card reader. So anything from a few hundred to over 1,000 cards per minute. Dividing by 60 and multiplying by 80 gives a character per second rate of up to around 1,500. Dunno about baud rate. Up to 15,000?

Data density is another interesting question. The cards were 7 thou thick, (0.007") so 143 per inch. 143x80 =11,440. So a 1" stack of cards could hold up to 11KB. A 64GB SD card is about the size of a postage stamp and costs maybe 10 USD.

[Zenith]

IIRC colossus was 5000cps, but continuous loop no start/stop.

That was the highest speed they could attain without too much risk of the paper breaking. Colossus could go faster. The paper must have been a special grade. The ends had to be glued together to make the loop. I'm sure I read that when they reconstructed Colossus, the original glue was considered too dangerous to use, and it took some effort to find a modern substitute.

[tggzzz]

Data density is another interesting question. The cards were 7 thou thick, (0.007") so 143 per inch. 143x80 =11,440. So a 1" stack of cards could hold up to 11KB.

Paper tape would have been higher: one character occupied 0.1in length by ~1in wide, i.e. 0.1sqin/character. The card equivalent would have been 3.25*7.4/80 or 0.3sqin/character. Plus paper tape was about half the thickness.

One came from census / sorting use cases, the other from comms.

[Zenith]

I never used paper tape. 3.25*7.4" so the 1" stack holding up to 11KB would be around 24 cubic inches. From what you say, paper tape holding 11KB would be 1100" - about 90 feet long. It would have to go on a spool.

Then there was magnetic tape. 10" reels of ½" tape. In my dealings with it, it was used for backup or data transfer. Years before, when disc storage was very expensive, there were tape operating systems. What early 60s sci-fi film with a computer, would have been complete without a bank of tape drives with wildly spinning reels?

[tggzzz]

I never used paper tape. 3.25*7.4" so the 1" stack holding up to 11KB would be around 24 cubic inches. From what you say, paper tape holding 11KB would be 1100" - about 90 feet long. It would have to go on a spool.

Spools were about 8in in diameter (and I remembered that correctly!)
https://taylorandfrancis.com/knowledge/ ... Paper_tape

Given a length of 2000ft, that was 240kchars in a volume of 64in³ (i.e. in a square box), or 3.75k/in³. From your figures, looks like punch cards were 11kchars in 3.25*7.4*1=27in³, or 0.4k/in³. Just as well land area is cheap in the USA!

And looks like I was right about 1000cps readers, i.e. 2.5m/s. Paper cut? Serves you right for not paying attention.
https://moca.ncl.ac.uk/iomedia/pt2.htm
N.B. the paper was guided onto that spooler by hand. I never had a problem

Then there was magnetic tape. 10" reels of ½" tape. In my dealings with it, it was used for backup or data transfer. Years before, when disc storage was very expensive, there were tape operating systems. What early 60s sci-fi film with a computer, would have been complete without a bank of tape drives with wildly spinning reels?

The Elliott 803 had mag film, not mag tape - i.e. with sprocket holes down the edges. Elliott was in Borehamwood, which also had a the largest movie studio outside Hollywood

[tggzzz]

Card feed rate would depend on the model of card reader. So anything from a few hundred to over 1,000 cards per minute.

Yup. And punched at 600 cards/min. Eeek!
https://moca.ncl.ac.uk/iomedia/pc.htm

[Zenith]

It was all horrible and a PITA. I don't feel the slightest bit of nostalgia for the days of cards, big spools of mag tape and computers, which had to sit in air conditioned rooms with a Halon drop in case there was a fire.

[EC8010]

What early 60s sci-fi film with a computer, would have been complete without a bank of tape drives with wildly spinning reels?

The Elliott 803 had mag film, not mag tape - i.e. with sprocket holes down the edges. Elliott was in Borehamwood, which also had a the largest movie studio outside Hollywood

Not just sci-fi; "The Italian Job" plot relied on introducing a naughty program to the Turin traffic computer via a big reel of magnetic tape.

16mm film entirely coated with magnetic material was "sepmag" (separate magnetic) and 16mm film with a magnetic strip was "commag" (common magnetic). I don't know if there was such a thing as 35mm sepmag, but I saw a lot of 16mm sepmag. Dreadful stuff. The film was nothing like as flexible as 1/4" tape so the head to tape contact must have been poor, resulting in poor and unstable high frequency response despite the 25 frames per second (TV) recording speed. From memory, a 16mm frame was about 13mm wide, and you could view it without twisting on a PicSync tabletop editor, so the frames must have been side by side rather than one on top of the other (35mm cinema film), so a 16mm frame would have been about 17mm long, call it 18mm to allow for a guard strip between adjacent frames. 25 x 18 = 450mm, so the film speed was about 18 ips. 15 ips gave excellent quality on 1/4" tape, easily reaching 15kHz. I have a feeling that commag managed 14kHz. Just about. Oh, and it was full track. A typical dubbing suite would have a full height bay with three sepmag transports and a fourth transport that was a crude telecine. It took a lot of power to shift that stuff and motion was locked by synchronous motors; it could be quite dangerous, especially when controlled remotely. But not as dangerous as the early Marconi/Stille machine https://creativeaudioworks.com/history/ ... eproducer/ that was essentially a bandsaw. It had multiple heads, not to be an early Watkins Copicat, but because a duff edit (improperly deburred weld) could take out a head.

Commag was even worse audio quality, with a magnetic stripe alongside the pictures. That's why films recorded their audio on a Nagra 1/4" tape machine synchronised to the camera by the clapperboard.

By the way, film people get really upset about "sprocket holes"; they are perforations, darling, or "perfs".

[Zenith]

What early 60s sci-fi film with a computer, would have been complete without a bank of tape drives with wildly spinning reels?

The Elliott 803 had mag film, not mag tape - i.e. with sprocket holes down the edges. Elliott was in Borehamwood, which also had a the largest movie studio outside Hollywood

Not just sci-fi; "The Italian Job" plot relied on introducing a naughty program to the Turin traffic computer via a big reel of magnetic tape.

Benny Hill did that. He was arrested later for indulging certain proclivities, which came out when he was helping a lady onto a bus.

I remember reading about an early video tape recorder with incredibly high tape speed. It was considered too dangerous to use back in the day - the 50s?

[tggzzz]

What early 60s sci-fi film with a computer, would have been complete without a bank of tape drives with wildly spinning reels?

The Elliott 803 had mag film, not mag tape - i.e. with sprocket holes down the edges. Elliott was in Borehamwood, which also had a the largest movie studio outside Hollywood

Not just sci-fi; "The Italian Job" plot relied on introducing a naughty program to the Turin traffic computer via a big reel of magnetic tape.

16mm film entirely coated with magnetic material was "sepmag" (separate magnetic) and 16mm film with a magnetic strip was "commag" (common magnetic). I don't know if there was such a thing as 35mm sepmag, but I saw a lot of 16mm sepmag. Dreadful stuff. The film was nothing like as flexible as 1/4" tape so the head to tape contact must have been poor, resulting in poor and unstable high frequency response despite the 25 frames per second (TV) recording speed. From memory, a 16mm frame was about 13mm wide, and you could view it without twisting on a PicSync tabletop editor, so the frames must have been side by side rather than one on top of the other (35mm cinema film), so a 16mm frame would have been about 17mm long, call it 18mm to allow for a guard strip between adjacent frames. 25 x 18 = 450mm, so the film speed was about 18 ips. 15 ips gave excellent quality on 1/4" tape, easily reaching 15kHz. I have a feeling that commag managed 14kHz. Just about. Oh, and it was full track. A typical dubbing suite would have a full height bay with three sepmag transports and a fourth transport that was a crude telecine. It took a lot of power to shift that stuff and motion was locked by synchronous motors; it could be quite dangerous, especially when controlled remotely. But not as dangerous as the early Marconi/Stille machine https://creativeaudioworks.com/history/ ... eproducer/ that was essentially a bandsaw. It had multiple heads, not to be an early Watkins Copicat, but because a duff edit (improperly deburred weld) could take out a head.

Commag was even worse audio quality, with a magnetic stripe alongside the pictures. That's why films recorded their audio on a Nagra 1/4" tape machine synchronised to the camera by the clapperboard.

By the way, film people get really upset about "sprocket holes"; they are perforations, darling, or "perfs".

Silicon/silicone

The 803 used 35mm stock with sprockets, dahling I haven't seen it working at TNMoC, and I wouldn't be surprised if it never works again.

Given the 803 was a 39 bit 2kIPS serial machine (576µs/instruction), bandwidth was irrrelevant! The mag film was primarily used as a more convenient form of paper tape.

[tggzzz]

It was all horrible and a PITA. I don't feel the slightest bit of nostalgia for the days of cards, big spools of mag tape and computers, which had to sit in air conditioned rooms with a Halon drop in case there was a fire.

5 channel 5/10cps teleprinters were the PITS; figure-shift letter-shift were a PITA. Mind you, card hand punches were worse; three fingered salutes were normal, FFS. Fortunately all that disappeared when ASR33s/DecWriters/Silent 700s were available. Fast forward to CTRL/META/ALT/ALTGR/etc, plus fondleslabs and smartphones, and scream.

But they were all we had - and sufficient for me to understand what a[1] compiler does (not how!) and for me to unwittingly re-invent the concept of an FSM.

[1] Tony Hoare's (RIP) seminal Algol 60 compiler. Met him at work once

[EC8010]

I remember reading about an early video tape recorder with incredibly high tape speed. It was considered too dangerous to use back in the day - the 50s?

VERA; designed by the Beeb. You need high tape to head speed to record frequency modulated (narrowband) video. So VERA ran the tape very fast. Ampex put four heads on a drum (quadruplex) and spun that drum at 15,625 rpm on an air bearing. Head signals were coupled by rotary transformers. The spinning heads wrote near-vertical tracks on 2" tape and produced cracking quality pictures (much better than the later 1" "C" helical format). However, audio quality was indifferent because the tape was optimised for video.

[tautech]

WOW thanks lads for the card and tape history lesson.

Never seen such up close but punched some card with a pen at HS which was sent away to be run somewhere Ahrs.
We got marked if out code ran properly and how complex it may have been.
IIRC we got a dot matrix printout back...well over 50 yrs back now.

[Robert]

All this talk of punched tape and film took me back to the late 70's. As a teenager I looked after a phototypesetting machine for a local advertising graphics company. I don't recall the make never mind model. It was a 2 bay 5ft high 19" cabinet mostly full of small plug-in discrete transistor logic PCB. It also had a flashlamp, rotating drum, stepper driven mirror and paper holeder and a lens. Data input was 8 level punched tape. Output was 4" "bromide" paper A 35mm film carrying the desired font was fitted to the drum and the lamp flashed when the correct image was in front of the lens. The mirror stepped the image across the paper. Linefeed was by stepping the paper up. No processors involved. You then developed the bromide, stuck it to the layout with cow gum. The layout was then photographed with a copy camera and a printing plate produced. This was ra huge advance on a IBM golfball typewriter and Letraset (dry rub-down transfers). Common faults seemed to be transistor failure. Fortunatly they had a full set of manuals for the machine. Input was prepared on a ASR-33. They had a hand punch for minor corrections. Tape punchings are called chad and are a hazard if you get then in your eye. I had Creed teletypes for RTTY at the time...
I did learn how to use Letraset properly and handle small bits of sticky paper from the layout artists.

I think I'm getting old....

[Zenith]

Typesetting was a problem well-heeled customers were prepared to pay for solutions to. There were alternatives to having compositors arranging movable type in frames; hot metal machines which could cast a complete line of type as dictated by a keyboard, then phototypesetting. When minicomputers and VDUs came along in the 70s, makers of typesetting equipment were early adopters. Word processors and personal laser printers have been commonplace since the mid 90s.

[tggzzz]

Odd facts...

Logica made early 80s dedicated standalone word processors with a portrait screen. Saw one, but didn't see it being used. Don't know the output device(s). Since it was sold to large companies, probably dot matrix and photo typeset.

~1985 I used a Mac to "typeset" a letter to an insurance company. They paid up, because I was right and maybe they hadn't seen a proportionately-spaced Times New Roman letter before. Printer: Apple ImageWriter dot-matrix.

~1987 I worked with a university which ran an AI benchmark (8 queens' problem) on a Mac and the contemporary Apple LaserWriter. The printer had better performance - its 68000 ran at 12MHz vs 8MHz.

[Zenith]

About 1985 the Amstrad PCW 8256 came out. Z80 based, no hdd, a floppy disc drive. Amstrad realised the application valuable to most home computer users was word processing. It had very good word processing software and it came with a printer. They were £399 as I recall and were a very versatile replacement for a typewriter. I knew a couple of people who bought and were happy with them.

Although it was positioned as a word processor, it was a capable 8 bit microcomputer. Interpreted BASIC was included and other applications, such as language compilers and a spreadsheet, were available at extra cost.

I'm sure if you paid more there were contemporary offerings that were better.

[mansaxel]

But not as dangerous as the early Marconi/Stille machine https://creativeaudioworks.com/history/ ... eproducer/ that was essentially a bandsaw. It had multiple heads, not to be an early Watkins Copicat, but because a duff edit (improperly deburred weld) could take out a head.

We have a Marconi / Stille machine at work. Also an Ampex 2" VTR. And a bunch of other interesting machines. If one of you lot show up here, I can take you on a tour.

[EC8010]

Good grief! I haven't seen a quadruplex machine for a very long time. But I think you may be a bit more than a motorcycle ride away?

[mansaxel]

Good grief! I haven't seen a quadruplex machine for a very long time. But I think you may be a bit more than a motorcycle ride away?

Central Stockholm. https://omoss.svt.se/about-svt.html