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Re: [LUG] Operating Systems We Have Known And Loved (And Hated)

 

On Sat, 5 Jan 2013, Simon Waters wrote:

I've seen multics and pdp-11s is my professional life. Mostly you know which people didn't have a well worked out upgrade policy ;)

My first Unix computer was a PDP 11/40.

I learned C on it, I also had a summer job sysadminning/developing some stuff for it. It ran Unix v6. I remember modifying the line printer daemon and I think my changes were fed back up the line, but it's hard to tell. We had no network then. The machine was expensive to maintain, but the chap in-charge was clever enough to work out that cancelling one quarters maintenance on the core memory would pay for an upgrade (from 256KB to 512KB) to DRAM. And on-going maintenance on DRAM was nothing compared to core, so it made sense. It was also twice the speed - reading core destroys it, so you need to write it back again which takes more cycles) That was a little over 31/2 years ago now. I know it was latterly upgraded with a 20MB winchester drive (From the 3MB internal one, and 1.5MB removables - 14" diameter, single platter) and ran Unix V7. It supported half a dozen "glass teletypes", a potter and printer. Programs were smaller then.

The universitys main computer was a Prime P550. They latterly upgraded to a 750 and later a 9950, but by then it was too late. Sun workstations had taken over for the computing department and CP/M, BBC Micros, Apple had taken over everywhere else.

I hated Primos - it just never seemed "right" at all. Then again the uny tried to shove 100 students onto one machine that had 4MB of RAM, all compiling COBOL, FORTRAN, Pascal and assembler. There was no C compiler, and wasn't a "commercial" programming language anyway, so it was never formally taught.

It was a funny old time as I'd started at school on BASIC mini/micro computers, learned IMP77 (a high level structured language) outside school, then stepped back in time when I went to the uny. Rooms of thundering TTY33's and having to enter programs initially on coding sheets where the girls in the operator room would type them in for us... (c1980) and COBOL )-: at its busiest it would take 2 days to get a program compiled and run... I think they were completely overwhelmed by the genration at the time who'd had prior access to 1:1 computing with Apples, Pets, CP/M boxes and so on, and wouldn't embrace "interactive" for a long time.

I also owned a pair of PDP8's too. Never did much with them and gave them away to a local school when I left Edinburgh.

The oldest computer I programmed was an Elliot 903. I had another summer job working for the hospital (mostly writing CAL software in Pascal), and they needed the software for the 903 upgrading due to a new (paper) tape format that their blood analysis machine produced.... It was backup to an ICL2900 monster. There is a working Elliot 903 in TNMoC.

The most "fun" old system I used was when I was still at school and I used to visit the local computer centre (Moray house) and I got to program/use their Interdata 7/32 in IMP77. They'd written their own OS for it (in IMP77) based on the Edinburgh system (EMAS) called Mouses. Going from that to the "old world" of batch processing on the Primes was a bit of a shock. (and disappointment)

Mouses/EMAS and Imp is an intersting parallel to the Unix and C of today.

The oldest computer I own is: http://unicorn.drogon.net/stuff/mk14.jpg although my Apple II's are almost as old: http://unicorn.drogon.net/lode.jpg

I almost bought a PDP11 last summer, but I'd have struggled to find somewhere to put it.

In-between then & now... Arc/RISC-OS, Transputers, Sparcs, i860's, ATmegas, PICs, the Internet... Raspberry Pi.

I don't find modern PCs exciting at all, but they're a means to an end.

Gordon

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