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The MacOS is fairly vocal when it has a problem. When an error occurs, dialog boxes appear with slightly useful information, or encrypted dire warnings. (Repeat after me, a Buss error has occurred...)

Linux OS is a little more bashful about proclaiming a problem, but if you know where to look, you'll find volumes of information. And I'll show you how the same can be said of MacOS X!

The kernel and most applications log errors in a series of text files in the /var/log directory. If you want to keep you system humming along smoothly, you should visit there often. In fact, if you have a rather small root partition, /var/log can choke your hard disk in no time!

One of the most helpful files is /var/log/messages. I consider it so important, I keep a link on my desktop. Any time an application acts up or crashes, viewing messages can provide clues as to what happened.

Here is an example:

Sep 14 15:14:30 Pismo_Linux httpd: httpd: cannot determine local host name.
Sep 14 15:14:30 Pismo_Linux httpd: Use the ServerName directive to set it manually.
Sep 14 15:14:30 Pismo_Linux httpd: httpd startup failed

After startup, I noticed that httpd (the Apache web server) displayed [FAILED]. While this log entry may not look as if it is much help, it allowed me to open the Apache config file and follow the instructions for setting the ServerName, allowing the web server to launch.

Another very helpful file is /var/log/XFree86.0.log. An incorrect font path can prevent the Xserver from running. This log file contains information on the XFree86.config file and even provides a key code for the severity of errors:

When I checked the log file, it had the following warning:

(WW) The directory "/usr/X11R6/lib/X11/fonts/CIP/" does not exist.

A quick look at the font directory told me I had a typo. CIP should have been CID.

Many of my initial errors in messages revolved around bad permissions on required files, missing directories, or errors in config files. Once eliminated, my system behaved much more predictably.

Because of its BSD/UNIX roots, this log files are also present in MacOS X! If you have the beta installed, look at the following file: /private/var/log/system.log.

The format is identical to /var/log/messages in Linux. Below are two text segments, one from each OS:

Linux log identifying the hard disks:

Pismo_Linux kernel: hda: IBM-DARA-212000, ATA DISK drive
Pismo_Linux kernel: hde: MATSHITADVD-ROM SR-8174, ATAPI CDROM drive
Pismo_Linux kernel: hde: ATAPI 24X DVD-ROM drive, 512kB Cache
Pismo_Linux kernel: hda: IBM-DARA-212000, 11513MB w/418kB Cache

MacOS X log identifying the same hard disks:

localhost mach_kernel: IOHDDrive drive: , IBM-DARA-212000, rev AR4AA51A [ATA].
localhost mach_kernel: IODVDDrive drive: MATSHITA, DVD-ROM SR-8174, [ATAPI].
localhost mach_kernel: IOATAHDDrive: Using U-DMA/66 transfer
localhost mach_kernel: IOHDDrive media: 23579136 blocks, 512 bytes each, write-enabled.

So it seems that no matter which OS you are running, you will be able to monitor log files to keep your computer running in tip-top shape!