[comp.sys.misc] AT DISKS AS 8\" CLONES

SAC.HQSAC-ACMI@e.isi.edu (02/23/87)

I have a pair of AT style 5 1/4 inch disks connected to an 8 inch
controller.  They work fine but i am not sure of one thing.  I
can set HEAD LOAD for when the drive is selected or when the door
is closed.  Since the motor is set to come on when the drive is
selected, which of the above is best for HEAD LOAD?  The drives
do make a nice "clank" sound when selected now (I have HL set for
when selected).  Will this cause the diskettes to wear faster
then the other method?

Thanks

Marc Frederick

boykin@custom.UUCP (02/24/87)

In article <4610@brl-adm.ARPA>, SAC.HQSAC-ACMI@e.isi.edu writes:
> I have a pair of AT style 5 1/4 inch disks connected to an 8 inch
> controller.  They work fine but i am not sure of one thing.  I
> can set HEAD LOAD for when the drive is selected or when the door
> is closed.  Since the motor is set to come on when the drive is
> selected, which of the above is best for HEAD LOAD?

Loading the head(s) when the door is closed (i.e. most of the time)
will cause the diskettes to wear out faster.  Hence, you want to
load the heads only when the drive is actually going to be used.
The advantage of keeping the heads loaded is access time; you don't
have to wait for the heads to come in contact with the disk.  Wearing
out the disk doesn't make this a big advantage, especially when
most controllers (via hardware or software) allow you to keep the
heads loaded for some number of seconds after the last access.  Doing
this means that the heads will be in contact with the disk ("loaded")
whenever you're doing repeated disk accesses (like a disk copy).
-- 

Joe Boykin
Custom Software Systems
...{necntc, frog}!custom!boykin