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

[Gordon Henderson <gordon+lug@xxxxxxxxxx>]

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

--
The Mailing List for the Devon & Cornwall LUG
http://mailman.dclug.org.uk/listinfo/list
FAQ: http://www.dcglug.org.uk/listfaq