On 17/04/2018 04:12, Charlie Gibbs wrote:
> On 2018-04-16, Martin Gregorie  wrote:
>
>> On Mon, 16 Apr 2018 21:40:21 +0100, Ahem A Rivet's Shot wrote:
>>
>>>  A traditional set of blinkenlights is impossible, the bus lines
>>> aren't exposed where you could attach lights (and they switch a bit too
>>> fast).
>>
>> Disagree: at least one microcomputer (the IMSAI 8080, as seen in the "War
>> Games" movie) had them way back in the mid-70s - and that was based on an
>> Intel 8080, so it must have been possible to write a firmware monitor to
>> emulate the effect of the handswitches and lamps on a PDP-8. However, the
>> 8080 was an 8-bit chip with 8 nregisters and 16 bit addressing, so at
>> least the number of switches and lights was manageable.
>>
>> But do it on a 64 bit chip with 16 32 bit registers and a 32 bit address
>> space? Some how I don't think so.
>
> Depends on how hard-core you are.  Remember the IBM 360/75?
>

Certainly hard core here; I have 7 4K core memory planes remaining
from my first attempt at building a computer (TTL, own instruction set)
45 years ago?

Started out with 96 of them in two blocks of 48 from a Marconi
Leo, reduced to only 8, then someone in Didcot wanted a plane to
experiment with, so just keep the remaining 7 in my mini museum.

I never used them anyway! Got hold of 4 off 256 by 1 static rams
and frigged a 128 by 8 bit memory; 128 bytes more than sufficient
to satisfy the excitement of having your own computer
back in 1973!

--- SoupGate-Win32 v1.05