Shadow Ram - HP Vectra XU5 Reference Manual

Shadow RAM

On HP personal computers, access to certain ROM data is enhanced by using shadow
RAM. During the POST, the BIOS and other ROM data is copied into high-speed shadow
RAM. The shadow RAM is addressed at the same physical location as the original ROM in a
manner which is completely transparent to applications. This technique provides faster
access to the system BIOS firmware.
POST Test
System BIOS Tests
LED test
Processor Test
System (BIOS) ROM Test
RAM Refresh Timer Test
Interrupt RAM Test
Shadow the System
ROM BIOS
Load CMOS Memory
CMOS RAM Test
Internal CacheMemory Test
Video Tests
Initialize the Video
System Board Tests
Test External Cache
Shadow SCSI ROM
Vectra XU Technical Reference
Description
Flash the LEDs on the control panel.
Tests the processor's registers. Test failure causes the
boot process to abort.
Calculates an 8-bit checksum. Test failure causes the boot
process to abort.
Tests the RAM refresh timer circuitry. Test failure causes
the boot process to abort.
Tests for RAM parity errors.
Checks the first 64 KB of system RAM used to store
data corresponding to various system interrupt vector
addresses.
Test failures cause the boot process to abort.
Tests the system ROM BIOS and shadows it. Failure to
shadow the ROM BIOS will cause an error code to
display. The boot process will continue, but the system will
execute from ROM. This test is not performed after a soft
reset (using [ ]+[
CTRL ALT
Checks the serial EEPROM and returns an error code if it
has been corrupted. Copies the contents of the EEPROM
into CMOS RAM.
Checks the CMOS RAM for start-up power loss, verifies
the CMOS RAM checksum(s). Test failure causes error
codes to display.
Tests the processor's internal level-one cache RAM. Test
failure causes an error code to display and the boot
process to abort.
Initializes the video subsystem, tests the video shadow
RAM, and, if required, shadows the video BIOS. A failure
causes an error code to display, but the boot process
continues.
Tests the level-two cache. A failure causes an error code
to display and disables the external cache.
Tests for the presence of SCSI ROMs. If SCSI ROMs are
detected, their contents are copied into the shadow RAM
area. A failure will cause an error code to display.
Power-On Self Tests
]+[ ]).
DEL
68