29 Oct
2017
29 Oct
'17
6:27 p.m.
From: Jon Elson
I'm not sure the original DEC PDP-10 (KA-10) used
microcode
No, it didn't; in part because it pre-dated fast, cheap ROMs (the development
of which was a considerable task in the /360 project - the wonderful "IBM's
360 and Early 370 Systems" covers this is some detail). The KA10 is built out
of FLIP CHIPs which carried individual transistors.
Another fun KA10 fact: it used 'hardware subroutines' - i.e. a clock pulse
would get to a certain point, and get conditionally diverted through some
other circuitry, later to come back and continue where it left off. Whee!
Noel
2 Nov
2 Nov
12:30 p.m.
On 29/10/17, Noel Chiappa via cctalk wrote:
Another fun KA10 fact: it used 'hardware
subroutines' - i.e. a clock pulse
would get to a certain point, and get conditionally diverted through some
other circuitry, later to come back and continue where it left off. Whee!
When I was taking a look at the CDC 1604 lately (btw, sadly two documents
are missing on bitsavers) I saw pretty much the same thing. Something
would set a flip-flop, go through the memory sequence, and continue from
the point it left off. This reminded me of the PDP-6 immediately (which
I'm very familiar with because of a logic-level emulator and verilog
implementation I've written [1]). The indexing and indirection mechanism
was also very similar. I suspect Gordon Bell was inspired by this
machine a bit. I think I'll mail him about the 6 again...
aap
[1] https://github.com/aap/pdp6
2639
days inactive
2643
days old
1 comments
2 participants
participants (2)
-
aap＠papnet.eu -
jnc＠mercury.lcs.mit.edu