Service Notes - Compaq 141536-002 - Deskpro EN - MT RAMBUS Maintenance And Service Manual

7. Each time the system boots, the system ROM saves a copy of NVRAM (including
CMOS, passwords, and other system variables) in the flash ROM. Should the system
become unstable, the last known good copy of NVRAM can be restored using a feature
called "power button override." To restore NVRAM, do the following:
1. With the unit powered down, press and release the power button.
2. Immediately after pressing the power button (during POST), press and hold the
power button until the unit powers down (approximately 4 seconds).
At the next boot, the ROM detects this "power button override" event and the backup
copy of NVRAM is restored.
Because of this feature, users cannot power off the computer immediately after powering
up. The video display must be active before the computer can be powered off.
8. The major core BIOS for the Deskpro EN is significantly changed from previous
versions. Some of the key changes include:
!
detailed F10 Setup help text via the F1 key
!
enhanced storage support from F10 Setup, including:
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!
new F10 Setup device information
!
service password that allows for back-door, power-on capability in the event a
password is forgotten
!
advanced interrupt controller (APIC) that provides more interrupt requests
(IRQs) for PCI IRQ mapping (this feature can be disabled in F10 Setup)
!
10-second POST time (may vary with slower storage devices or removable
media)
!
master boot record (MBR) security, which provides recovery from malicious
or accidental damage to the boot disk's MBR
!
notifies user during POST if the boot disk or its MBR has changed
!
changes to either the boot disk or the MBR require:
! saving a new MBR image
! disabling MBR security
! restoring the backup MBR to the disk (unless the boot disk has changed)
!
some administrative utilities (like fdisk) cause changes to the MBR that are
detected in the next reboot
7-2

Service Notes

detailed device viewing information
choice of booting to IDE or SCSI hard drives
execution of IDE DPS self test
support for LS-120 and ZIP drive booting (without a 1.44-MB diskette drive
increased maximum drive capacity from 64 GB to 2 terabytes
SCSI SMART failure support
adjustment of configurable device parameters, including:
! translation mode options: bit shift (default), LBA assisted, user (must specify
desired geometry), and none (hard disk defaults used). Two "industry
standard" translations inhibits "connect-and-go" access to hard disk data
! Emulation type option, which allows users to force the BIOS to treat the
device as the specified device type
For an LS-120 and ATAPI ZIP drive, emulation modes include
1. diskette (ZIP drive only; to boot as A:/ drive)
2. hard disk
3. none
The device's native type is always "none". For the Zip drive, none means
"other" device type: for the LS-120 drive, none means "diskette" device type.