Contents of the PARK.DOC file
PARK -- A new routine to park the heads of one or both fixed disks
The heads of fixed disks should be left in the parked position
whenever the drive is not in use, so that if the machine is jarred
or the power is dropped, the heads will land on an unused portion
of the platter. IBM provides a way to do this, but only in
the DIAGNOSTICS diskette (under PREPARE SYSTEM FOR RELOCATION).
Several BBSs have had PARK routines available for download, but
universally they handle only one hard disk and universally the
cylinder number at which the disk heads should be parked is hard-coded
in the program.
This PARK.COM routine determines, for either or both hard disks,
where to park the heads (by trying ever-higher cylinders until it
finds a cylinder number to which the disk cannot move), and leaves
the heads there. It does it separately for the first and second
drives, so that it is usable even in systems that have two dissimilar
An earlier version did the seeks one cylinder at a time; the current
version first moves 100 cylinders at a time, then 10 cylinders at
a time, and finally one cylinder at a time. On a Seagate 225 (612
cylinders, 4 heads, 20 megabytes), this reduced the time from an
intolerable half-a-minute to less than 1/2 second.
The files are: PARK.DOC this DOC file
PARK.ASM assembler language source
PARK.COM the executable module, obtained
by processing PARK.ASM with the
MASM, LINK, and EXE2BIN programs.
Carl Hayes (SYSOP, NN5I BBS, 214-960-2730)