<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
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
, can be configured to boot from a network rather than from disk. Such a system can thus run as a diskless workstation