Re: safe file systems

Larry McVoy (lm@cobaltmicro.com)
Wed, 24 Sep 1997 12:22:23 -0700

: [write re-ording]
:
: I think even my cheapish SCSI disks (which have a 1 (maybe 2?) MB cache)
: will do this. I assume here a system reset will not affect them, but
: power-failure did last time I checked. (But you can twiddle with the tables
: on them and modify the way it writes data back, etc).

The default on every SCSI & FC disk I've ever seen (and I've seen a
fair number including drives from HP, Seagate, Quantum, IBM, Maxstor,
and probably others I'm forgetting) is to /not/ do write caching. If
the drive says the write is done, it is done.

You can, as you mentioned, change this behavior, but the default as shipped
from the vender is that it does not do write caching.

And no work station vendor (Sun/SGI/HP) that I know of turns them on - it
would be highly unreasoable to do so.