Maintenance and Service Guide

Nonvolatile memory usage
Nonvolatile memory type Amount (Size)
Does this memory
store customer data?
Does this memory
retain data when
power is removed?
What is the purpose of this
memory?
Real Time Clock (RTC) battery
backed-up CMOS conguration
memory
256 bytes Yes Yes Stores system date and
time, LAN settings, and
limited security settings.
Battery-backed SIO RAM 64 bytes Yes Yes Stores basic power
management rmware
settings and power loss
error reporting.
DIMM Serial Presence Detect
(SPD) conguration data
256 bytes per memory
module, 128 bytes
programmable
No Yes Stores memory module
information.
System BIOS ROM 16 Mbytes Yes Yes Stores system BIOS code
and PC conguration data.
Nonvolatile memory type How is data input into this memory?
How is this memory write-
protected?
How is this memory reset or
cleared?
Real Time Clock (RTC)
battery backed-up CMOS
conguration memory
Using the F10 Setup utility or changing
the Microsoft Windows date & time.
This memory is not write-protected.
HP recommends password-
protecting the F10 Setup utility.
The CMOS conguration memory is
cleared by removing the 3 V battery
from the motherboard for at least 5
minutes.
Battery-backed SIO RAM Programmed at the factory. Code is
updated when the system BIOS is
updated.
A utility is required for writing data
to this memory and is available on
the HP website. Writing data to this
ROM in an inappropriate manner can
render the PC non-functional.
The SIO RAM memory is cleared by
removing the 3V battery from the
motherboard for at least 5 minutes.
DIMM Serial Presence
Detect (SPD) conguration
data
Programmed by the memory vendor. The memory does not get changed
under standard operating
conditions.
Third-party tools may be used to
write to this memory region.
System BIOS ROM System BIOS code is programmed at the
factory. Code is updated when the system
BIOS is updated. Conguration data and
settings are input using the F10 setup
utility or a custom utility.
A utility is required for writing data
to this memory and is available on
the HP website. Writing data to this
ROM in an inappropriate manner can
render the PC non-functional.
An F10 menu “Apply Factory
Defaults” combined with a “Restore
Security Settings To Factory
Defaults” will clear any custom user
data and settings retained in this
memory.
Nonvolatile memory usage 85