Thursday, March 01, 2007

"By, you were lucky..."

My friend, erstwhile mentor and visiting professor colleague Rod Goodman and I were reminiscing a few days ago about our first experiences (~1977) with the Intel 8080, which arrived on a circuit board with 1K bytes RAM, a 1K byte EPROM and absolutely no software. We were having one of those conversations inspired by Monty Python's four Yorkshiremen sketch (and thanks to Dave Snowden for this link from his excellent blog):

"When I were a lad, we only had 4K bytes of RAM and a hex keypad"

"Hex keypad! By, you were lucky. We only 'ad 1K of memory and had to key in t'boot loader by 'and in noughts and ones before we could even start work".

"Well you were lucky. We were so poor we could only afford noughts..." and so on.

But the truth is (and I realise how perilously close I am to becoming a grumpy old man parody here) that my fellow graduate students and I really did have to start from scratch and make all of our own development tools. I recall that we first had to write a cross-assembler, in Algol-68, on the university mainframe: an ICL 1904S. We took advantage of the fact that the mainframe was accessed by electro-mechanical 'teletypes' which were fitted, as standard, with paper-tape punches. We got hold of a paper tape reader and interfaced it to the Intel 8080 development board (designing by hand the necessary interface electronics and device driver code - remember this is long before 'plug and play'). Then we were able to write symbolic 8080 assembler on the mainframe, generate 8080 machine code on paper tape, and load that directly into the 8080 development board to test it. Of course the edit test cycle was pretty long, and not helped by the fact that our lab was two floors from the mainframe terminals, so to speed things up we invested in a special device that allowed us to directly 'edit' the paper tape. The device allowed us to make extra holes and cover over - with a special kind of sticky tape - unwanted holes. Here's a picture of this marvellous device.

So, to anyone out there who grumbles about their software development tools I have only one thing to say. "You're lucky you are. When I were a lad..."

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