24 Oct
2025
24 Oct
'25
8:33 a.m.
On Oct 24, 2025, at 8:00 AM, cz via cctalk
<cctalk(a)classiccmp.org> wrote:
OS level caching of disk devices is a gennable option in M+ with split I/D.
It's actually pretty impressive; the system can do read-aheads, and also writes can
be deferred (which makes turning off the system hot very bad). I think it can also cache
the directory entry table and even a small cache of 256kb or so makes a nice performance
difference.
It's also a standard feature in RSTS/E, which can allocate up to 496 kW to the storage
cache (plus additional memory, if you want, for a ramdisk). I haven't tried to see
what the performance numbers look like with and without, that would be an interesting
experiment.
paul