Compaq 4000N - Manual (Page 142)

Chapter 8 BIOS ROM
Compaq Deskpro 4000N and 4000S Personal Computers
First Edition - September 1997
8-2
8.2 BOOT FUNCTIONS
The system supports new system boot functions to support remote ROM flashing and PC97
requirements. This system also supports the EL Torito specification for bootable CDs.
NOTE: This system will not boot CDs intended for use in Compaq ProLiant and
ProSignia products.
8.2.1 BOOT BLOCK
This system includes 24 KB of boot block ROM that provides a way to recover from a failed
remote flashing of the system BIOS ROM. Early during the boot process, the boot block code
checks the system ROM. If validated, the system BIOS continues the boot sequence. If the
system ROM fails the check, the boot block code provides the minimum amount of support
necessary to allow booting the system from the diskette drive (bypassing the security measures)
and re-flash the system ROM with a ROMPAQ diskette. Since video is not available during the
initial boot sequence the boot block routine uses the keyboard LEDs to communicate status as
follows:
Num Lock Caps Lock Scroll Lock
LED LED LED Meaning
Off On Off Administrator password required.
On Off Off Boot failed. Reset required for retry.
Off Off On Flash failed (set by ROMPAQ).
On On On Flash complete (set by ROMPAQ).
The boot block area of ROM is always write-protected.
8.2.2 QUICKBOOT
The QuickBoot mode (programmable through the INT 15, AX=E845h call) skips certain portions
of the POST (such as the memory count) during the boot process unless the hood has been
detected as being removed. The QuickBoot mode is programmable as to be invoked always, never
(default) or every x-number of days.
8.2.3 SILENTBOOT
When in the SilentBoot mode, the boot process skips certain audio and visual aspects of POST
(such as the speed beeps and screen messages). Error messages are still displayed. The
QuickBoot mode is programmable (through the INT 15, AX=E845h call) as to either TERSE
(default) or VERBOSE mode.