15 Nov
2007
15 Nov
'07
5:04 a.m.
On 14 Nov 2007 at 23:36, Roy J. Tellason wrote:
Multi-user in an 8-bit context doesn't sound real
terrific to me, for some
reason, though I don't see a problem with multiprocessing if it's done
right.
It could be remarkably good, but you have to work within the
limitations of the architecture. The x80 CPUs didn't have any good
way to dynamically relocate code and data and had a fairly small
addressing space.
We simply went to a (pcode-type) interpreter that serviced all of the
users. It cut down on redundant code and since we were executing
BASIC programs, the speed penalty wasn't too awful.
I received a note last week from a one-time customer in Japan who
mentioned that they were talking about phasing out the old code
they'd written back in the 80's for the system we wrote in 1979 for
an 8085 (supporting 5 users) and later ported to SCO Xenix. He
remarked that they'd added to the programs over the years with no
problems. This is more than 20 years after the company offering the
language went out of business.
I've still got the source code somewhere.
Cheers,
Chuck