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Even Older Man Yells At Whippersnappers


On Wednesday 20 September 2017 10:29:08 Larry Martell wrote:

> On Wed, Sep 20, 2017 at 5:09 AM, Gregory Ewing
>
> <greg.ewing at 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.

Chuckle, love it Larry. But then I am sure it was not that much of a 
problem for you.

That super elf? Used a broadcast audio cart in an old machine whose 
capstan was badly worn so it played a regular cart at about 90% speed 
for its non-volatile memory. Didn't bither the elf a bot, never had it 
fail to load and run the next copy of my program.  I had saved 4 or 5 
copies on a 2 minute cart. Then did another for backup, and a 3rd cart I 
took home. Fast fwd to 2017, it and a paper copy of that machine code is 
on the top shelf here in this room.  Yeah, I've had packratitis all my 
life.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>