espen@well.UUCP (Peter Espen) (11/28/87)
Does the ShutDown command under the 'Special' MenuBar item in Finder 6.0 set the R/W heads on third party SCSI disks to save areas for power-down and moving? What exactly does this command do? espen@well
dlw@hpsmtc1.HP.COM (David Williams) (12/01/87)
Well on the jasmine innerdrive 90 on the mac II it parks the heads, on the jasmine Direct drive 80 on my Plus it parks the heads. So I guess it does the same thing on any mac drive that can park its heads!
dbw@crash.cts.com (David B. Whiteman) (12/03/87)
Whether the "Shutdown" command from the Finder parks the heads on 3rd party drives depends on the 3rd party. From my experiments in trapping the SCSI dispatch trap while shutting down, all the SCSI drivers that I have tested, which is in noway representative of all drives, do not sent a shutdown command to the drive. The volume is flushed, ejected, and unmounted, but there is no head seek to the innermost cylinder, nor is the Start/Stop SCSI command issued. I wrote a special head parking program which does send the Start/Stop command on shut down. When I use it I can actually hear the heads park on my drives. According to Seagate's manual for my drive, which is a Seagate 225N, the drive can withstand 40g's as opposed to 10g's if the heads are parked. The Seagate 225N is used in some of Apple's HD20SC's, all of GCC FX20's, Jasmine 20's, MacMates Reflex 20 and none of these drivers parked heads during shutdown from the Finder when I tested them about 7 months ago. Of course this may have changed with a software upgrade since then. Most of the larger drives park heads automatically when the power is turned off, so no shut down command is actually needed in this case.
jdm@ut-ngp.UUCP (Jim Meiss) (12/04/87)
In the documentation that came with my DataFrame 30-XP it says that automatic head parking is done by holding down the option key when you select shutdown. Perhaps this works on other drives as well. Jim Meiss jdm@ngp.utexas.edu