Hard Disk Drive
Troubleshooting
The troubleshooting of hard disk drive
problems could probably fill an entire book. When it gets down to
the bottom line, however, there are three basic kinds of problems you
might have with a hard disk drive. Each requires very different
troubleshooting actions and different levels of risk.
I’ve been working in the computer industry for almost 20 years
now. During that time, I’ve heard a number of my less-technical
friends and co-workers tell me that they’re “running out of
memory” on their computer. After I ask a few questions about
what they mean, it’s clear to me that they don’t understand the
difference between “memory” and “disk space”.
If they were to ask a salesperson at a computer store to sell them some
“memory” for their computer, they might get some very
expensive hardware that wouldn’t solve the real problem. Just so
that this doesn’t happen to you, I thought I might give you a few
different explanations of what “memory” and “disk
space” really are, so that you know what to ask for and why.
Journaling is a feature of Mac OS X that is intended to protect the
integrity of the files stored on your hard disk drives. Using this
feature can protect against some of the kinds of file corruption that
frequently caused crashes, startup problems, etc., in Mac OS 9.
To learn more about journaling, read the excellent article at:
http://www.larryjordan.biz/articles/lj_journaling.html
The
scripts below will turn on (or off) journaling for all connected
drives.
While these scripts have been tested by me and appear to
work fine on OS X 10.3.x and 10.4, I provide them here without warranty
or support, just “as is”. If they work for you and solve
a problem for you, great! If they don’t work, cause you to lose
data, lose your hair, or anything else, you agree that you assumed all
responsibility and liability when you decided to try the script out on
your system.
The scripts can be executed from the command line or
a cron task.
A power-saving and disk-life-saving aspect of modern operating
systems is the ability to shutdown the hard disk drive when it is not in
use. This activity, called “spindown” occurs
automatically any time the operating system determines that the hard
disk drive hasn’t been accessed in a while.
Normally, this is a
good thing. It reduces wear and tear on disk drives, lowers system
temperatures (because spinning drives generate heat), and saves electric
power. But there are times when spindown can be a problem.
For example, if spindown is set to a very short value (like one minute),
the drive may spin down more often than it should. As a result,
you might find normal activities on the Mac being much slower than you
expect. Paging through a Microsoft Word document as you read it,
for instance, might take an unusually long time because the computer has
to spin up the hard drive before it can read and display the next
page.
The script below adjusts the spindown time for a disk.
If you enter “0″ for spindown time, you disable spindown and
the disk drive will always run. This might be OK for a server
that’s running constantly and needs to respond quickly to requests at
all hours, but is probably overkill for a desktop Mac, and would likely
drain the battery of a Mac laptop very, very quickly. A value
larger than “0″ will specify the number of minutes of disk
inactivity the computer should wait before spinning down the hard disk
drive. For example, entering “csh setspindown 30″ would
cause the computer to wait for 30 minutes of inactivity before spinning
down the hard disk drives.
To use this script, copy and paste the
lines below into TextEdit. Save the file as
“setspindown” onto your Mac’s hard drive. Go to a
Terminal window and navigate to the location of the file. Enter
“chmod a+x setspindown” to make the script executable.
When you want to use it, type “csh setspindown xx” where
“xx” is the number of minutes you want the computer to wait
before spinning down the hard disk drive. If the computer prompts
you for a password when you execute the script, the password it needs is
that of an administrator. If you don’t have administrator
permissions, you probably can’t run this script.
This script has
been tested in MacOS X 10.3.x and 10.4, and appears to work as
designed. No warranty of any kind is made by me that this script
will work on your system, though I see no reason why it wouldn’t.