🚀 go-pugleaf

andrew@cubetech.com (Andrew Loewenstern) writes:
[...]
>It would be nice if NeXT would either beef up the cache allocation, or
>make it settable via a file...  It would be cool if Mach did what
>NetWare does...  NetWare uses ALL unused memory for file, FAT, and
>TurboFAT caching.  A 32-meg NetWare server just cranks, even with a
>LOT of disk access going on.  So if Mach turned all available memory
>into disk-cache and then released it as memory was needed (until the
>disk cache reaches a certain point), we'd prabably get more speed.

But Andrew, it DOES!  Mach keeps pages of files resident after they've
been read (not just executable).  Check out the "filemem" command, it
tells you what pages of a given file are resident.  It doesn't have
a manpage.

I came across this when  wanted to test disk throughput with a 10-20MB
file (to swamp small buffering schemes).  Second time around was several
times faster, and it couldn't have been those puny buffers the kernel
tells us about at boot-up.  Coming to think of it, what ARE those buffers
anyway?

>But Chris Lloyd is right...  the SCSI drivers (and many more low-level
>drivers) seem to be pretty screwed up.

Yeah, 700K max. throughput on those fast 520Meg Fujitsus is ridiculous.  So
is < 1 MB/sec on a 3.5" Gigabyte drive that can do 1.2 MB/sec physical (from
the platter, or so I'm told) and something like 4 + MB in burst mode.

>andrew

Marcel