This article is from the Apple II Csa2 FAQ, by Jeff Hurlburt with numerous contributions by others.
A RAM disk is a block of memory which your computer uses like a disk. To create a RAM disk on your IIgs ... o- Boot a ProDOS-8 or DOS 3.3 diskette; or, start your computer with no boot and press CONTROL-Reset to get to the Applesoft prompt. o- Press OpenApple-Control-ESC (all three keys at once) to get to the Desk Accessories menu and select "Control Panel". o- In the Control Panel menu, select "RAM Disk". o- Set "Minimum RAM Disk Size" and "Maximum RAM Disk Size" to the the same value = size of the RAM disk you want. If you have enough RAM left over to start your operating system and run your favorite application, a good RAM disk size is 800k. o- Press Return to set the value. Exit the Control Panel. Exit the Desk Accessories menu. Turn OFF the computer. When you next power up your computer, your RAM disk will be ready to use. By: David Empson