from
The Free On-line Dictionary of Computing (8 July 2008)
PROM monitor
<operating system> a small program stored in {PROM} (or
{ROM}), responsible for both loading the {OS} and providing
some means to analyse OS {crashes}. It may also have some
sort of {user interface} which can be used to examine and
change the contents of memory, control the boot process
(specifying arguments to the {kernel}, or changing where to
look for the it), and so forth.
The main difference between a PROM monitor and a {bootstrap
loader} is that the PROM monitor regains control when the OS
terminates. This may enable a {wizard} to find out what went
wrong if the OS crashed, although it is usually of little help
for the average {sysadmin}.
(1996-12-03)