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back to article Remembering the Commodore PET 2001

Bah. Kids today with their Nintendo Wiis, iMacs, 30-inch HDMI screens, PDAs and CD-Romses. This old box logo Back in the Golden Years of electronics, personal computers required a Master's degree or a crippling social disorder to operate and it was better that way. And colors? You had two options: stunning beige or get the …

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Real computers

I started with a Northstar and then moved onto a Superbrain - with *two* floppy drives (and an unfortunate experience with a Gemini S100 machine).

We laughed scornfully at Pet owners as we spent hours trying to work out the cabling for RS232 dot-matrix printers. No games for us (except Zork of course), we were running social security calculations written in Z80 Cobol.

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Ah! The old days ...

And nostalgia isn't what it used to be, either.

But being serious, I'm currently writing a degree level course part that has to use the command line - what I take for granted I'm having to explain in great detail. And I;im sure that I'm missing a load of things that I'll have to explain in greater detail.

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Happy

I feel old

I use to dream of having a Commodore Pet but we could not afford it and my dad bought a Video Genie (TRS-80 rip-off) which was my first real intro into computers and programming. I loved that machine to-bits and it is was amazing what you could do with a small amount of RAM.... I feel that some programmers today could learn a lot about how to write good, tight, efficient programs or maybe I am just getting old....

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Ahhhh nostalgia...

... just the mention of those part numbers starting 65... brings back happy memories.

First computer I learned to program on was a PDP8e that we had at school, followed by a SWTPC 6800 system with Flex (ahhh, the days of the +++ prompt).

The first computer I owned was an Acorn Atom, 1MHz 6502 with 12K RAM. Didn't stay 1MHz for long since I found I could overclock the processor to 2MHz, although the RAM was nominally 650ns 2114s, so I had to swap them all around until the ones that couldn't cope with the exrta speed were at the bottom of the display memory.

Back in those days it was fun trying find ways of squeezing as much as possible into that amount of memory. Life just doesn't have the same challenge with 2GB to play with, and I haven't touched assembly code on a PC in about 4 years.

When I want the fun of the old days, I get out my PIC development board and see just how much I can do in 2K of assembly language on the thing.

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@Dave Lawton

That's what I meant - stick an ethernet card in the Arc and use it as a bridge. Like I say, it'll never never work, but that hasn't stopped me hitting Ebay hard for the bits that I need...

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Re:Overclocking - ZX81

The ZX81 had two modes, FAST and SLOW, unfortunately in FAST mode you lost the display. By switching modes at an appropriate rate you could get a tune out of the TV.. 16 whole K of memory. My still working ZX81 still boots in under two seconds, somewhere it all went horribly wrong..

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Paris Hilton

Still alive

The college I went to, in the mid-1990s, had one sitting near the entrance of the computer department. The man in charge was wont to say that it was the most expensive machine in the room, which was otherwise filled with Apple Macintoshes. It was a later model PET, with a proper keyboard, and it still worked. In fact it felt indestructable, and I expect it still works today. When we're dying it will be still alive. When we're dead it will be still alive.

I choose Paris Hilton as my avatar, because she also only has a tiny amount of processing power.

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Pirate

How to destroy a PET

Did you know the PET was probably the only computer you could down by writing a BASIC program?

There was a certain poke command you could do which shorted the 5v line and eventually caused the power supply to shut down.

Oh how we would enter a computer shop (not many back then), enter a quick program with a suitable delay and stand outside the shop watching the computer go off. he he.

Happy hacking days....

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@Stuart Halliday - blowing things up from BASIC

Seem to remember Monochrome IBM PC monitors were quite prone to blowing if they got the wrong line sync frequency.

Once upon a time I hit the 6845 video controller timing registers with a few OUT instructions from BASIC (I think it was on a Hercules graphics card rather than the original text-only display card), pushed up the line sync rate, got a high pitched squeal out of the monitor and blew the horizontal scanning circuits.

The flame icon seems appropriate in the circumstances.

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Unhappy

You cynical bastards !

I can see the editorial meeting:

' OK so we chuck out a few cheap and cheerful articles about a few old computers and let the greybeards fill a few pages with 'When I were a lad' responses'

Shame on you El Reg, such cynical manipulation of a large portion of your readership !

Mind you, if the Dragon 32 makes the list .....

:)

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Magazines

I remember at the time the different magazines such as Byte. They had articles on most of the platforms. It was interesting to see what the other brand users where doing with their computers.

Billy Higinbotham, Bellport, NY

The ASCI guy

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Heart

@ Alan Potter

The shop i worked in in TCR was Eurocalc (about half way up on the right - I think it's a Carphone Warehouse now?).

Here's one that will throw many people - the ITT 2020, Apple licenced the Apple ][ to ITT (mainly because Apple couldn't make enough of them) and ITT botched it by having an extra bit in the graphics output, consequently in grahics mode every 8th pixel was a solid vertical line - also it was a really cheap looking silver/grey colour (although the same case design as the standard Apple ][).

In those days TCR was run by The NLJM (Loretta Cohen out of Lion House, Peter Ingoldby owned Eurocalc - et al)....it's now run by SEAM......good days though.

Reading this thread gives me a desperate need to type in a Yorkshire accent for some reason?

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re: Stuart Haliday

FYI, the command was "poke59458,62", and it didn't short the 5V line (as it would be pretty hard to do that from software) This command would speed up the display on older machines--don't remember the tech details, but you can probably Google it--think it had something to do with fooling the display not to wait for the CPU. Newer machines with the larger monitor ("fat 40" they were sometimes called) had a CRT controller chip. Poking to this location on these machines would cause the equivalent of turning the refresh rate too high on a modern monitor, and CRTs with weak flybacks could be made to smoke and die. And also, as someone else mentioned, this did NOT have several 6502s, just one. It had several 6522s (VIAs--versatile interface adapters) which provided many IO functions that were pretty far ahead of their time. (and the 8050 floppy drive could store half a meg per side of a 5 1/4 floppy--not too bad for 1979--you could also issue the drive a command to format a disk or copy one disk to another, turn off the computer and walk away--the drive had its own 6502 and OS)

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Alert

bloatware: an epiphany

The coin finally dropped while reading the posting about a tiny endless loop that ran till overflowing a counter:

A classic optimization is loop unrolling, in which loop code is repeated in many juxtaposed sets of mostly the same instructions. This technique minimizes the test-and-branch-if-... logic and probably allows peephole optimization much wider scope to work in the unrolled loop than in the direct and obvious translation of the loop with one test/branch sequence each time through the loop.

I have been reading, and sympathizing with, complaints about bloatware for years, but nobody has ever provided any figures about how much bloat comes from aggressive loop-unrolling versus featuritis, so I'm going to get off my bloatware soapbox until I hear from the experts.

Are there any out there that care to chime in? (Quantitative data earnestly desired.)

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Thanks for the memory.

Still got this one, After reading the article , I convinced my Pops to pull it out of the attic, and take some pics,. - The thing still works , but the tape deck is pooched, we think the drive belt has decayed. The only other problem is the *A* key which was the fire button in 'Commodore Invaders' , might have taken a bit of a beating :) .- Learnt to program on this baby, and realized there is life for a social retard, been with computers ever since and liking it very much thank you !. I remember when we had this I bragged about it at school, got called a liar by my teacher Mr. Jenkins , So I sneaked the manual to school to show everyone, and got a break time detention for being a smart ass.- all at the tender age of 7, Ahh the happiest days of our lives !!

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OMfG

I am 30, I was programming at 5. say no more...

ok I will then. By the time I was 10, I had tried nearly 95% of the available machines on the market, Spectrum, Texas 80 (TRS80), Commodore, Dragon 32 and 64 and prototype 128 just before they went bust (again), Amstrad CPC (all 4 models), EINSTIN (This was a fantastically advanced machine, so much so they went bust in development and just couldn't afford a launch for a product 3 times more expensive than the next best toy on the market, but at the time nothing else would allow you to edit the software while it was running in the background and still allow a second process to be started. I remember the OIRC? and MSX designed machine (the Idea with MSX was to allow people to design there own machine and so long as it met certain design spec all applications would run on it)

I the Dragon 64 1st edition was made on the cheap, by piggybacking memory on top of other memory to double up on it, with a small switching circuit to flip between the 2 quickly (in usage) this was to stop people from rejecting there product when everyone else had 64k or 128k machines out there. later models had proper memory design, but having 2 different machines with 64k memory did lead to some software issues, and some times the machine wouldn't run big software packages like 'sprite' etc without a 'poke' entered before running it, fortunately they only had about 1000 machines with this problem. I remember most (nearly all) games were microsoft, and the basic OS was microsoft, and when loading many games there was a 4bit colour image of gates himself to look at while you made tea and waited for the games to load.

Memory's.......

take me back any day. :)

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Anonymous Coward

Why this didn't sell well in Germany...

I heard that this did not sell very well in Germany becuase 'PET' meant something else in German. But Commodore did not learn from their mistake and named the next model 'vic' which when pronounced in German sounds like an even ruder word!

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Anonymous Coward

My first large program was on a PET

My father ran a hotel business and had a staff payroll of about 25 people to do every week. It took him ages looking up all the tax tables and filling in the accountys sheets. I said I would computerise it for him if he bought me a PET and he did. I was only a teenager at the time.

The program worked well (but took ages to load). I had to EXACTLY match the tax tables (including rounding down in exactly the same way as the goverment did) so that the end result exactly matched the manual calculations he did. After a month, my father just used my system and it took him 30 minutes rather than 3 hours!

Only problem was he did not want me to use the PET after that in case I mucked it up!

Steve

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All our yesterdays

Didn’t the PET have Micro$oft Basic, complete with garbage collector bug, no change there then, whatever happened to them!! I upgraded from a UK101 kit to the PET and spent many a happy hour under the hood learning 6502 assembler and burning eproms. Oh to be young again *sigh*

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Unhappy

I feel bad about continuing this thread, but...

@Anonymous coward - I think it's likely that we worked opposite each other. What's more, I then moved over the road, as it were...

If only we could communicate directly...

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Those were the days

I learnt to program in Basic and Comal on one of these beauties when I did my YTS at Portsmouth ITeC.

It had a IEEE488 bus with 5¼" disk drive.

I wrote a snazzy, text graphical, fruit machine simulator with it

Tho' if you hit return at the READY. form, it did throw a "Can't read Y." error message.

Class!

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Go

Oh, the humanity!

I'm with Steve Scott in that I also spent very many hours back in the late 70s typing listings into our school PET from magazines. The only ones that worked first time were a 'Jumbo Jet Simulator', which was a dot on the screen(!) which you had to keep on a downward flight path and a fantasy RPG which was called something like 'The Tower and The Valley'.

Ah, happy days! I'm waiting for the Spectrum, Dragon and Atari ST articles...

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Heart

too young too remember but not too old to care

i'm no tecchie (wordsmithing's my game) but yeah, that machine makes great sounds ! i got an emulator and dled some funny files that makes all the original sounds from that machine. ideal for chip tunes ! viva el commodore! and thanks to 8 bit weapon for the fantastic idea :D i do love those sounds...

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And only £1000 (+cassette recorder)

My software business's roots are with a PET: I took out a bank loan to buy one of the first 32K large keyboard models, and the program which has earned me good money since 1989 was first written on my PET (then moved to BBC then PC). Back c.1980 the UK Commodore Users Group used to send out magazines with code listings printed (IIRC) black on green - perhaps the world's first copy protected software!

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Tsk, computers in boxes?

You're all soft - real men used stuff on PCBs with dodgy power supplies and bolted on expansions.

Bring back the MK14 and the Tangerine!

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Happy

Re: ITT 2020

It wasn't botched, it was a "europeanised' Apple ][

The extra memory bit was added deliberately, I think for the 60Hz/50Hz frame difference between US and Europe so UK-spec displays could be used. There was extra RAM added for the extra bit required, but it was 'on the end' of the display space. Official ITT software, and things which didn't bypass the monitor (the BIOS, for the youngsters), worked fine. It was the Apple-specific programs, especially those which wrote directly to video RAM, which had every 9th bit blank. I vaguely remember at least one chess program like that. The 'official' software knew where to get that 9th bit's value from.

I remember a friend who went to the US on holiday to buy an Apple ][. Compuer + holiday cost him less than just buying the computer in the UK. A few years ago I was in a surplus store in California, where there was a big cardboard bin full of Apple ][s, going for $15 each. Sad...

I also know of one large UK Telco that, back in the early 80s, used an Apple ][ as the main link between a VAX and a telephone switchboard in their call centre. The switchboard console was connected via a serial line at some weird bitrate, and the apple serial card was the only thing they'd found that could be easily programmed to match it. It sat there for years without a problem, with the lid off to keep it cool, converting between 9600bit/s RS232 and the switchboard console.

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Flame

Overclocking an Amstrad 1512

I remember being told how to by a new crystal from Maplin or Tandy, to get another 1mhz or so out if it.

Although I now know we've lept forward a decade....

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Happy Days

My first computer was the PET2001 which I bought on HP - took ages to clear that debt! I played around with the built-in Basic and eventually progressed to Assembler on the later PETs. I was fascinated by the idea of connecting external equipment to the expansion facility, which was a huge connector along the right hand side of the motherboard. So I played around with fairly simple interfaces to start with - switch inputs, LED outputs, DC motor controls etc. all implemented using mostly assembler coded software.

At work, we had a contract to provide a control system for an automated robotic inspection system, which used several Stepper motors, position encoders (Grey Code) and miscellaneous switch inputs and control outputs. I was of the opinion that this could be best achieved using a 4032 PET and a purpose built interface, connected to the expansion port, rather than trying to implement the entire system in hardware, which was the original concept. The hardware was based around several 6522 via devices and the software was a hybrid of Basic and Assembler.The system worked very well for a long time and was later adapted to suit several other robotic inspection devices.

Although I really liked the instruction set for the 6502, I also experimented with the Dragon 32 with its 6809 processor - now that one had a great architecture and a super instruction set !! Several later projects were built using that processor............ Happy Days indeed!

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Dragon 32!!!

god i still got a working one of those

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Ben
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MSX anyone?

Still a great machine, even though it failed to take off anywhere other than japan. Mind you not a bad thing considering it was MS-Basic based....

Spectrum, Spectrum plus, C64, electron, bbc, RM 380Z (yes - the school where chucking it out in 88/89 and said i could have it and it even had the graphics adapter. B+W graphics rule). I even had a Superbrain with a 5MB (I think) winchester. Nemesis on the MSX though, what a game. Used to know Mark Butler too from Imagine. He lived up the road from me.

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Stop

Comments

Do we need a thousand and one comments about "my first computer was a blah blah"? Let's keep any future comments in this series to the reviewed computer in general - especially if you came to the computing scene late in life (and by late I mean 1981 onwards)!

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Pillick

I knew some idiot would post up the poke code required to give Curators of computer museums a headache!

My excuse for not remembering the exact reason why it would go up in a puff of smoke is easy. Hey man I was only 14 at the time!

I always wanted a PET since I was 14, but of course could never afford one.

When Ferranti finally closed its doors 20 years later, I wandered around an empty factory floor seeing what I could pick up cheap.

There in a corner was an unwanted broken Pet. I had to own it! This was my very last chance of owning my first technological icon!

How much did they want for it?

I pay a fiver and it sat in my living room staring back at me for a further 3 years before I gave it to a loving museum. (I got married).

Sniff...

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@Andy Gibson

Apart from the fact that your comment makes no reference to the Commodore Pet 2001, I think most people here are actually enjoying this discussion. Before you ask, did join the "Computer Scene" as you so eruditely put it, before 1981.

But I have this feeling that you are either (a) someone who's been made redundant recently and is feeling ill-will to any sort of merriment, or (b) the sort of project manager I hate, being a project manager myself.

I also think you mean "specifically" rather than "in general", but that's just my pedantic side coming out...

Please go and find a thread which shares your lack of humour

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Anonymous Coward

Wow!

There was 4 of us with these. We had a contact within Commodore so upgraded our 8K machines to 64K, needed to upgrade power as well so the cassette had to go external. We developed games for the "PET" using these machines and then compiling them to get into the 8K, if we could'nt do it we had tools to shift some of the code into the input/output memory to fit, which was also a neat way to stop people copying them because as soon as they "saved" program it would overwrite the buffer memory. We also made "sound" boxes out of old metal tobacco tins with components inside and attached to the output serial port. What "geeks" we must have appeared but as all of us where IBM'ers working on "real" computers it was just a social thing.

The day IBM brought out there PC we were all called to meetings with our managers and given the option of stopping work on our "hobby" or leaving IBM. Unfortunately we all made the wrong decision and stayed with big BLUE.

One thing I do remember about these were how easy it was to fix them when they went wrong. You could juggle the memory to isolate errors...

Raptor.

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:( I want one

first computer I ever had was the relativly new IBM PS1 (pre-HDD think it ran from a Rom chip but I could be mistaken) and I miss that shed loads.

I also had a Sinclare Spectrum but it wasn't the same :(

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Heart

Second life

In 1982 I won a Commodore 4000 and disk drive for my school in a competition. It was the first disk drive the school had ever owned - my maths teacher kissed me when she found out ...

Years later - about 1990 - it was surplus to requirements, and they offered it to me. These things had an IEEE488 parallel interface as standard, so they were brilliant for instrumentation, so "my" PET took on a new role doing superconductor characterisation tests in Oxford. I understand that it only retired from that about 2000.

My greatest feat was to write a VT52 (subset) terminal emulator for it, in basic. The only connection I had was done by going IEEE488 -> RS432 (current loop) with one convertor, then RS432 -> RS232 with another, then through a Gandalf box into the university network. 50 baud was pushing it.

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Nev
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Good Book

"On The Edge" by B. Bagnall

Really good history of Commodore's Computer years.

Great insight into everything from 6502 design to the

last Amigas.

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