On Wed, Sep 20, 2017 at 7:29 AM, Larry Martell <larry.mart...@gmail.com> wrote:
> On Wed, Sep 20, 2017 at 5:09 AM, Gregory Ewing > <greg.ew...@canterbury.ac.nz> wrote: > > > > Never mind that fake assembly rubbish, learn a real assembly > > language! And hand-assemble it and toggle it into the front > > panel switches like I did! > > 1979, I was working at Bausch and Lomb in Rochester NY. We had a 16 > bit Data General Nova 'Minicomputer'. It had 4 registers, called > accumulators. It had 16 front panel toggle switches, one for each bit, > one that said 'deposit', and one that said run. It had a dial with > stops for AC0, AC1, AC2, AC3 (for the 4 accumulators), PC (program > counter), address and contents. > > When you powered up the machine it did not boot. You had to hand enter > a short bootstrap program in binary. Do to this you had to turn the > dial to address, key in a 16 bit address, click deposit, turn the dial > to contents, key in a 16 bit line of assembly code, click deposit, and > repeat this for each line of code (there were like 5 or 6). Then key > in the address of where you wanted to run from turn the dial to PC, > deposit, and click run. Any mistake and it would not boot. Often took > 3 or 4 tries. > > After a few weeks of this I was sick of it. I had the boot code burned > into an EEPROM (which I had to send out to be programmed). Then I > build a very small wire wrapped board with the EEPROM and an > oscillator and few TTL chips. I tapped into the 5V power on the CPU > board and used the leading edge of that to trigger a one shot which > 'woke up' my circuit, and caused it to clock out the code from the > EEPROM and load it to the appropriate place, set the program counter > and start the program. I drilled holes in the CPU board and mounted > this with little plastic standoffs. > > I did this all on my own, coming in on the weekends, without company > approval, and when it was working I showed my boss. He was blown away > and he was sure we could patent this and sell it. He had me formalize > the design, write it up, have an actual PCB made, go to the company > lawyers, the whole 9 yards. Then Data General announced the new > version of the Nova .... with auto boot. > -- > https://mail.python.org/mailman/listinfo/python-list > That's crazy! The oldest computer I ever owned was a 1984 Tandy 1000. I actually still miss that thing. It had an option where you could change the 8-bit music that played on startup. Luckily for me, it took 5.25" floppys. -- https://mail.python.org/mailman/listinfo/python-list
