boot disk
<operating system> The {magnetic disk} (usually a {hard disk})
from which an {operating system} {kernel} is loaded (or
"bootstrapped"). This second phase in system start-up is
performed by a simple bootstrap loader program held in {ROM},
possibly configured by data stored in some form of writable
{non-volatile storage}.
{MS-DOS} and {Microsoft Windows} can be configured (in the
{BIOS}) to try to boot off either {floppy disk} or {hard
disk}, in either order. By default they first check for the
presence of a {floppy disk} in the drive at start-up and try
to use that as a boot disk if present. If no disk is in the
drive they then try to boot off the hard disk.
Some {operating systems}, notably {SunOS} and {Solaris}, can
be configured to boot from a network rather than from disk.
Such a system can thus run as a {diskless workstation}.
(1997-06-09)