RAM: or Ram Disk, which is represented on the Workbench screen by the Ram Disk icon, is an area of the Amiga's internal memory that is set up as a file storage device. Files, directories, and - available memory permitting - entire floppy disks can be copied to RAM: for temporary storage.
The size of RAM: is dynamic. It is never any larger than necessary to hold its contents. Therefore, it is always 100% full. Its maximum size is limited by the amount of free memory.
The primary advantage of RAM: is speed. Since it is electronic, rather than mechanical, storage and retrieval are almost instantaneous. The disadvantage of RAM: is that data stored in RAM: does not survive when the computer is turned off or rebooted.
Applications commonly use RAM: for the storage of temporary files created during the use of the program or backup files created when the program is exited. RAM: can also be used for the storage of experimental script files, as a destination for testing command output, and whenever the creation of a file on an actual disk is too slow, risky, or inconvenient.
The most efficient way to copy information from one disk to another on a single-floppy system os to use the Ram Disk:
Be careful when using RAM: for storing important files. If the Amiga loses power, has a software failure, or you reboot, everything stored in RAM: is lost. Be sure when working with RAM: to regularly back up any important files on a floppy disk.
AmigaDOS also provides a recoverable Ram Disk, which has the device name RAD:. The contents of RAD: survive reboots and most software failures, making it a safer place for work files. (Data in RAD: is still lost if the computer is turned off.)
RAD: is not automatically created. To activate a recoverable RAM Disk, double-click on the RAD icon in the DOSDrivers drawer of the Storage directory. To start RAD: whenever you boot, copy the RAD icon to the Devs/DOSDrivers drawer on the Workbench disk. When RAD: has been activated, a disk icon labeled RAM_0 appears on the Workbench screen.
Unlike RAM:, the size of RAD: is fixed. The size is set in the RAD: mount file's HighCyl parameter. Change its size by entering a different value for HighCyl. A HighCyl entry of 79 results in a RAD: with the same capacity as a normal 880 KB floppy disk.
On an Amiga with more than 2 MB of RAM, you can create a floppy-size RAD:; the default as configured by the MountList is floppy-sized. By copying your Workbench files into this RAD: and reassigning to it all the directories normally assigned to the Workbench disk, it can be used as a recoverable Workbench-in-Ram. This allows you to reboot from RAD: instead of from the Workbench disk.
You can also set up multiple RAD: devices of different sizes by copying the RAD: mount file and changing the name and unit number.
