old processor architectures [was Re: The Strange Birth and Long Life of Unix - IEEE Spectrum]

[D. Hugh Redelmeier]

| From: James Knott <james.knott-bJEeYj9oJeDQT0dZR+AlfA at public.gmane.org>

| > I still have some paper tapes for them.
| 
| Anyone recall using the PDP-8 RIM loader?

Yes.  You had to enter it using the switches.  It was just used to
read in the BIN loader tape.

The actual code was silk-screened on the console.  Roughly 16
instructions.  To key each in, you had to set the 12 data switches and
then press "deposit".

Self-modifying to cut down on the size.

Since memory was core (magnetized doughnuts), it was non-volatile.
Most of the time the BIN loader stayed intact, even across power
cycles.

The Altair was similar.  In fact, I'm sure it's system design was
inspired by minis like the PDP-8.  But its ram was volatile.  I'm sure
glad mine had an add-on board that held EPROM (it could read and
program 2708s).

The original Altair kit had only 256 bytes of memory.  You had to buy
expansion kits for more.
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