Keeping your Macintosh well maintained

All computer systems rely on its files to perform most of their functions. To ensure a healthy system, make sure the components on the computer that manages your files are in good order. There are typical problems found on Macintoshes, namely Desktop Files and Parameter RAM corruption. This article describes tools and procedures to deal with each of these problems, and describes disk repair and preventive measures.

Disclaimer: I am not responsible for damage to your computer and loss of data, arising from the use and/or misuse of these instructions.

Many of the Macintosh maintenance procedures described here, can be carried out easily by using a free software utility called "TechTools", which is available from MicroMat.

Desktop files

On a Macintosh equipped with System 7.x, there are two index files that are used to speed up file retrieval; these are known as "desktop files". Throughout the time a computer is operational, files will be deleted, overwritten, and added to the hard disk. When desktop files go out of sync with the true contents on the hard disk, system performance slows down; in the extreme, corrupted desktop files can lead to bizzare system behaviors, such as an unusable Trash icon, and inaccessible files.

There are two ways to rebuild desktop files: a) Hold the Option and Command (the open Apple) keys down when the computer is booting up; b) Delete the Desktop DB and Desktop DF files. The first approach is easiest to do if you only need to rebuild one computer's desktop files at a time; the second approach works only if you have special software to delete these two invisible files, and is recommended for administrators of public computer labs.

Floppy disks also have desktop files that are prone to corruption. These can be rebuilt by holding the Option and Command keys down while inserting the floppy disk into the computer.

Parameter RAM

This computer memory is used to store information about the computer's startup disk, monitor resolution, and network type. When information in the Parameter RAM becomes corrupted, the computer may refuse to boot properly, and the monitor may refuse to display a picture. To fix this, you can "zap" the Parameter RAM by holding Command, Option, "p" and "r" keys when the computer is booting up. If your computer's monitor does not display a picture, and you are certain the monitor is OK, the battery that keeps your Parameter RAM alive may need replacement.

After zapping the Parameter RAM, your network settings may need to be reconfigured. If you are connected to your network through an Ethernet port, you need to run the Network, or AppleTalk Control Panel to set the appropriate port. Do nothing if you normally connect to the network through the LocalTalk port.

Disk repair

Hard disks and floppy disks are prone to storage errors and physical defects. Because a hard disk is hermetically sealed, one finds fewer physical defects on hard disks than floppy disks. Most serious problems on floppy disks are due to poor disk handling.

Apple Inc. has a utility called Disk First Aid, which can be used to perform basic repairs on disks. Disk First Aid CANNOT repair the disk you used to start the computer, but can Verify if the disk needs repair.

To repair your hard disk, boot the computer with a CD-ROM, or a floppy disk that has the appropriate system files (Finder, System, and Enablers), and run Disk First Aid from the CD-ROM or floppy disk. Select the hard disk icon, and click Repair. To repair your floppy disk, run Disk First Aid from your hard disk, select the floppy disk icon, and click Repair.

More powerful disk repair

Norton Disk Doctor is capable of performing minor file problems Disk First Aid is not able to detect or repair. In many cases, it can repair the startup hard disk; you may need to run several scans to make sure the problem is resolved; I would however recommend booting your computer with a CD-ROM, and running Norton Disk Doctor from a floppy disk.

Preventive measures

About half of all floppy disk repairs performed at MICOL fail because these disks contain media damaged by dust particles or physical scratches. Usually, physical damage occurs on the file(s) people need most. The best prevention is to keep several copies of important files in different disks, and keep disks in different locations.

Floppy disk drive heads should be cleaned once a month with a floppy drive cleaning kit. These kits are sold in mosts electronics appliance stores. Simply put a few drops of Isopropyl Alcohol (which is what the "cleaning solution" is) on the cleaning disk's felt surface; insert the cleaning floppy disk into the drive, and ignore your computer's complaints that the disk is not readable. If you're using TechTools, there is a Clean button you can click on to treat the floppy drive heads with your cleaning disk.

Run Disk First Aid once a week to verify the health of your hard disk. Run Norton Utility's Speed Disk once a month to defragment your hard drive.

Clean the rollers and the tracking ball in your mice once every month. Shutdown the computer BEFORE unplugging the keyboard or mouse; failure to do so may result in serious damage to the Apple Desktop Bus circuitry found on the motherboard.