RAMdisk driver

Copyright 1997 Alistair Riddoch

This is a very simple block devices driver. At bootup it is not initialised.
ioctl(fd,RDCREATE,..) will allocate 64K of RAM to be used as a ramdisk for
the device reffered to by fd. Minor numbers 0-7 can be used for 8 separate
ramdisks. The ioctl(fd,RDDESTROY,...) call frees up the memory. Only the
superuser can currently make these calls. A utility "ramdisk" has been
provided with the standard elks commands package and on the last root
disk to install and remove ramdisks. I see this as a way of having temporary
space on a system which uses a root filesystem stored in ROM, and could be used
to hold a filesystem image copied from ROM. The code could also be easily
adapted for a ROMdisk.

Al (ajr@ecs.soton.ac.uk)

13th Oct 1997