On 2022-11-01 11:20 a.m., Paul Koning via cctalk wrote:
tents. The result is that the OS only has to deal with the device every
30 characters or so (RSTS case) or even less often if the buffer size is
larger.
Consider disk for another example. With very rare exceptions, disks do DMA: the OS
points to the place where the data lives, supplies a transfer length and starting disk
position, and says "go do it and tell me when it's finished". Newer devices
like the MSCP controllers support a queue of requests, but even simple devices like the
RK05 will do a full transfer without CPU involvement.
How mqny old systems required partial transfer for disk io, for swapping
overlays in and out?
paul
Ben.
