19 Dec
2023
19 Dec
'23
7:54 p.m.
On Thu, Dec 14, 2023 at 06:29:35PM -0500, Noel Chiappa wrote:
Interestingly, other early systems don't seem to
have thought of this structuring technique.
How early does that have to be? MP/M-1.0 (1979 spec) mentions this,
as "Resident System Processes"
http://www.bitsavers.org/pdf/digitalResearch/mpm_I/MPM_1.0_Specification_Au…
It was a banked switching, multiuser, multitasking system for a Z80/8080.
It mentions 5 such processes.
Later versions, and the 8086 version still had them. The MP/M-86 docs mention
'Terminal Message', Clock, Echo and 'System Status' processes. I
believe the
first was spawned one per console.
(Some of the internal structures suggest it was intended to support swapping,
but I don't know if that was implemented in terms of disk swapping)
DF