HARD DISK WISDOM
by Bill Dieck, KUB, September, 1987

(Common sense about how to treat hard disks)

The Hard Disk is a fairly rugged and reliable piece of hardware,
but since it represents a considerable investment, I was thinking
of ways to increase the time between failures.  Preventative
maintenance can be broken down into four simple rules:

     1. Keep it Kool
     2. Don't Move
     3. Park It
     4. Let 'Em Run

It helps to know the reasons behind the rules.

[Keep it Kool]  the disk is both an electrical and mechanical
device.  In general the life expectancy of any electronic device
is dramatically increased when the operating temperatures are
kept low.  Normally the only things we as hard disk users can do
is make sure the ventilation is correct.  This translates to
keeping filters clean, fans operating, and keeping the room
environment clean and at a reasonable temp.  (65 to 70 degrees). 
Make sure the ventilation slots are not blocked by books, papers,
etc.

[Don't Move It]  Well at least while the disk is power on
(remember the disk spins as long as you have power to the
computer).  The disk pick-up heads that read/write the data 'fly'
just a few thousands of an inch above the disk.  If the heads
come in contact with the disk surface (called Head Crash) they
can permanently and catastrophically damage the disk.  Even if
the disk is not running (power up), you should take care and
treat it for what it is.  That is a High Tech., specialized close
tolerance precision machine.  A couple of G's impact force can
mis-align the delicate Head/Disk alignment.  Just a few inches of
drop to a hard surface can create a G or two of impact force. 
Portable computers are generally more rugged by use of "shock
mounts" to install the disk into the case.  Remember, less
movement is less chance of damage.

[Park It]  This is for the owners of disks that require parking. 
Not all disks require this (check your operators manual). 
Parking the heads means removing the heads from the data area of
the spinning disk BEFORE you power off.  The heads 'float' or
'fly' on a Laminar air cushion formed by the spinning disk.  When
the disk stops, the air cushion disappears and the heads can
contact the recording material on the disk, potentially damaging
the heads/disk.  The command may vary, but the result is the
same.  Shipdisk, Parkdisk, etc. all remove the heads from the
disk.  Most newer models do this automatically when the disk
electronics detects a power loss, and do not require the manual
command.

[Let 'Em Run]  Generally speaking, start-up stress is more
damaging to a machine than letting it run for several hours.  If
you intend to use the computer within a couple of hours, let it
run.  You will limit the stress due to variations in speed,
temperature, voltage, etc. that occur during Power on/off cycles.
