Jeremy Chadwick <free...@jdc.parodius.com> wrote: > On Tue, Aug 30, 2011 at 11:04:43PM -0700, Kevin Oberman wrote: > > ... the standrad does not specify EXACTLY what triggers a > > transition from standby to ready (PM2 to PM0). Only that it is > > something that requires media access. A write does not > > necessarily require media access if you define "media" as the > > disk platter. > > You're correct -- "media access" could mean, literally, "accessing > the platter" OR it could mean "LBA read/write I/O". Then comes > into question whether or not the drive returning something from > its on-board cache would count as "media access" or not. > > T13 should probably clarify on this point, and this is one I do > not have an answer for myself. I strongly believe "media access" > means "LBA read/write I/O" and regardless if it's data that's in > the on-board cache on the disk or not. I wonder if this behaviour > varies per drive model.
Given a standard which is, shall we say, "open to interpretation", I think the liklihood approaches 100% that it has been interpreted differently by different manufacturers -- or even by different firmware authors within a single manufacturer. I would be amazed if the behaviour did _not_ vary among drive models. _______________________________________________ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org"
