QMS 2425 Reference page 135

This type of memory contains data and/or machine-executable
instructions that can be read but not modified. This information is not
lost when the printer's power is turned off.
RAM is the memory your printer uses to perform each task. It can be
written to and read from. Once a task is complete, the memory is free
again to be used for another file. This memory is volatile, so if your
printer loses power while a file is being sent, you must resend the file.
The number and type of features you can run on your printer simulta-
neously depend on the amount of RAM you have and how that RAM
is distributed. Your printer comes with either 8 MB or 24 MB of RAM,
but it is upgradable to 128 MB by adding Single In-line Memory Mod-
ules (SIMMs).
Also called a virtual disk, the RAM disk is an area of RAM that is used
to simulate an additional hard disk. Data can be written and read
more quickly than on a hard disk, but a RAM disk loses any informa-
tion stored on it when the printer's power is turned off. The spooling
buffer is a RAM disk client if a hard disk is not available.
The printer's SCSI port allows you to connect up to three optional
SCSI hard disks and the optional CrownCopy scanner, providing stor-
age for fonts, emulations, and other files. Hard disks are also used to
increase the amount of collation that can be accepted and provide a
secondary storage area for spooled data, while providing virtual
memory capabilities.
This is an optional internal hard disk. "Integrated" refers to the fact
that all of the controller electronics are on the drive itself, so no sepa-
rate adapter card or expansion slot is required.