HP Vectra VT 6/xxx HP Vectra XU 6/xxx and VT 6/xxx PCs - Technical Reference M - Page 42

Power-on Self-test Routines

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5 POWER-ON SELF-TEST ROUTINES This chapter summarizes the Power-On Self-Test (POST) routines. The first section indicates the order in which the tests are conducted. The second section lists the error codes which can be reported, along with theirmeanings. The third section summarizes the suggested corrective action appropriate for each error code. VIEWED ON THE SCREEN Each time the PC is turned on, or a reset is performed, the Power-On Self-Test (POST, also referred to as the HP System Hardware Test) is executed. The POST process verifies the basic functionality of the system components and initializes certain system parameters. It starts by displaying the initial "Vectra" screen. Although the POST routines are run as normal, their progress is not displayed (other than on the eight-stage graphics histogram underneath the "Vectra" label). If POST detects an error, the results are reported on a View System Errors screen. During the POST, the BIOS and other ROM data is copied into high-speed shadow RAM, where it 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. If the POST is initiated by a soft reset [CTRL] [ALT] and [DELETE], the RAM tests are not executed and shadow RAM is not cleared. In all other respects, the POST executes in the same way following power-on or a soft reset. The POST detects when a hard disk has been replaced, or if there have been changes in the size of the hard disk. However, it does not report an error. The POST performs the tests in the order described here: POST Test LED Test System (BIOS) ROM Test RAM Refresh Timer Test Interrupt RAM Test Shadow the System ROM BIOS Load CMOS Memory Description System BIOS Tests Tests the LEDs on the control panel. Calculates an 8-bit check-sum. Test failure causes the boot process to abort. Tests the RAM refresh timer circuitry. Test failure causes the boot process to abort. 1 Tests for RAM parity errors. 2 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 tests is not performed after a soft reset (using [CTRL] [ALT] and [DELETE]) Checks the serial EEPROM and returns an error code if it has been corrupted. Copies the contents of the EEPROM into CMOS RAM.

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5
POWER-ON SELF-TEST ROUTINES
This chapter summarizes the Power-On Self-Test (POST) routines. The first section indicates the
order in which the tests are conducted. The second section lists the error codes which can be
reported, along with theirmeanings. The third section summarizes the suggested corrective action
appropriate for each error code.
VIEWED ON THE SCREEN
Each time the PC is turned on, or a reset is performed, the Power-On Self-Test (POST, also
referred to as the
HP System Hardware Test
) is executed. The POST process verifies the basic
functionality of the system components and initializes certain system parameters. It starts by
displaying the initial “Vectra” screen. Although the POST routines are run as normal, their progress
is not displayed (other than on the eight-stage graphics histogram underneath the “Vectra” label). If
POST detects an error, the results are reported on a
View System Errors
screen.
During the POST, the BIOS and other ROM data is copied into high-speed
shadow RAM
, where it
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.
If the POST is initiated by a soft reset [CTRL] [ALT] and [DELETE], the RAM tests are not
executed and shadow RAM is not cleared. In all other respects, the POST executes in the same
way following power-on or a soft reset.
The POST detects when a hard disk has been replaced, or if there have been changes in the size
of the hard disk. However, it does not report an error.
The POST performs the tests in the order described here:
POST Test
Description
System BIOS Tests
LED Test
Tests the LEDs on the control panel.
System (BIOS) ROM Test
Calculates an 8-bit check-sum. Test failure causes the boot
process to abort.
RAM Refresh Timer Test
Tests the RAM refresh timer circuitry. Test failure causes the
boot process to abort.
Interrupt RAM Test
1
Tests for RAM parity errors.
2
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.
Shadow the System ROM BIOS
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 tests is not performed after a soft reset (using
[CTRL] [ALT] and [DELETE])
Load CMOS Memory
Checks the serial EEPROM and returns an error code if it has
been corrupted. Copies the contents of the EEPROM into
CMOS RAM.