What is a RAM disk, and why would I use one?

You can set aside a portion of your computer's memory to function like a disk drive, called a RAM disk. With a RAM disk, you can save and retrieve files very quickly, but the files are stored only temporarily. This feature is not available on all models of the Macintosh.

Using a RAM disk is faster and conserves power because the computer uses less energy and time to access RAM than it does to access a hard disk or a floppy disk.

PowerBook users may want to use a RAM disk to maximize battery life. Commonly used files could be stored on the RAM disk, which requires less power to access than a hard disk drives. Also, accessing frequently used files from RAM allows the PowerBook to spin down the internal hard disk more often.

Memory assigned to a RAM disk is not available for opening programs, so keep this in mind when you select the size of your RAM disk. It should typically not be more than 25% to 50% of your available memory or other applications may not have enough RAM to function properly.

To create a RAM disk:

1. Select the memory control panel from the control panels menu item under the Apple menu.

2. Click On to create the RAM disk.

3. Drag the lever to choose the percentage of available memory you want to use for your RAM disk. Choose a size large enough to accommodate what you want to put on the RAM disk, but not larger.

4. Close the Memory control panel.

5. Select Restart from the Special menu.

• Don't store your only copy of a file on a RAM disk. Keep an extra copy on a hard disk or a floppy disk.
• Before using a program on a RAM disk, test the program on another disk (hard disk or floppy) to make sure it works properly.
• Always save the contents of your RAM disk on another disk before turning off your computer.

• Click on the RAM disk icon on your desktop then select Erase Disk from the Special menu
• Drag everything in the RAM disk to the Trash then select Empty Trash from the Special menu
• Shut down your computer, then turn it back on.

Note: If file sharing is active, you may not be able to erase a RAM Disk. Use the File Sharing control panel to verify the status of file sharing.

For additional RAM Disk information, see the following articles: