Friday 4 September 2009

There are computers, and there are 'Real' Computers

In the past I've obviously had a bad habit of throwing out the photo's that mattered, but keeping the photo's that didn't matter. Hence a while ago I found these two pieces of nostalgia from my mainframe computer operating days. And yes I did operate both of these computers, including the constant mag tape loading/unloading, printer stationary changing and alignment, button bashing, etc.

The first shows part of a basic Honeywell 2000 Series mainframe computer of circa 1974 vintage. It was actually from the second major upgrade of a 1968 vintage original Honeywell 200, which originally had just 8K of memory!


The photo clearly shows the punched paper tape readers to the right, the operator's console in the centre, and slightly obscured between them is the 80 column punched card reader. On the edge to the left was an online 132 column revolving cylinder high speed impact printer (probably capable at best at 30 seconds per page, but was actually much slower as the computer printed as it processed). Off the photo to the right was a row of five rather slow and cranky vacuum chambered magnetic-tape drives, one of which held the 'BRT' - the tape containing all the programs required to run each 'batch processed' job, of which only one could be run at a time and which stopped at required intervals to allow operator intervention. Octal (base 8) was used to communicate with the computer via the Teletype console on this 2000 machine as the original 200 version had a large illuminated push button console. (Push 126 into the I address, set Admode from 2 to 3 by pushing once, replace 152 in the Contents with 153 by pushing 153 in, push Enter on the Address line, then push the Run button. - And that was just to restart the currently running program!!).

The second photo is from about ten years later, the early-mid 1980's, and shows part of an ICL 2956 mainframe computer. This machine still used 'batch processing' but could run several jobs at the same time by 'time slicing' the CPU between them, had offline printing (printouts were spooled during processing), and had modem communications link capabilities for remote data input and remote print output. No punched paper tape on this computer, which is a shame as by now I had become an expert in reading all those holes visually myself.


The bottom left of the photo shows the operators console, now a VDU with a PC style qwerty keyboard, and with two higher speed (probably 2 to 3 seconds per page) 132 column impact printers behind. To the right shows part of the row of higher speed and higher density magnetic tape drives. I think we started with seven of these on the original 2946, with at least two more added later. More important to this generation of mainframes was the long row of (originally 'Winchester' style) fixed and exchangeable disk drives, one of which I was obviously sitting on in order to take this photo!

And then I moved on into a new world of PC computing......!

Edit:

For more information on both these computers, and some better photo's, visit:

http://en.wikipedia.org/wiki/Honeywell_200
Which has a superb photo of the illuminated flashing 'button bashing' console of the Honeywell 200.

http://en.wikipedia.org/wiki/ICL_2956
Which also has in the External Links some good photo's of the aforementioned rows of disk drives!