25 Sep
2015
25 Sep
'15
6:20 p.m.
On 9/25/15 4:43 PM, dwight wrote:
Boot strapping a machine isn't impossible. It may
be difficult but not impossible.
I boot strapped a IMSAI with a "DigitalSystems" disk drive and controller.
I'll admit I did know 8080 code but I had to start from scratch on the
disk controller.
No nice little WD controller chip to start with, just a 12X12 board to TTL.
I didn't even know it was a DMA device when I started.
I've trouble shot a 20 bit mini with no schematics.
A lisp machine would clearly be difficult but not impossible for a determined
hacker.
If it was designed to run it can be made to run again.
Dwight
No, it's not impossible but damned difficult. First there is the FE
code that gets loaded from disk.
The FE then loads the LM uCode. Once the LM uCode is running, it then
loads Genera. In addition,
I don't think the disk format was described (at least at the level
necessary for booting). Oh and
neither the micro-instructions nor the macro instructions are documented
in any way.
Some work has been done to build an emulator but it was based upon
trying to emulate the code
that ran on the Alpha. No one to my knowledge has created an emulator
for the 36xx series
machines.
TTFN - Guy