Maintenance and Service Guide

Nonvolatile memory usage
Table 14-1 Troubleshooting steps for 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?
How is data entered into this
memory?
How is this memory
write-protected?
HP Sure Start ash
(select models
only)
8 MB No Yes Provides
protected
backup of
critical System
BIOS code, EC
rmware, and
critical
computer
conguration
data for select
platforms that
support HP
Sure Start.
For more
information,
see Using HP
Sure Start
(select models
only)
on page 175.
Data cannot be written to this
device via the host processor.
The content is managed
solely by the HP Sure Start
Embedded Controller.
This memory is protected
by the HP Sure Start
Embedded Controller.
Real Time Clock
(RTC) battery
backed-up CMOS
conguration
memory
256 bytes No Yes Stores system
date and time
and noncritical
data.
RTC battery backed-up CMOS
is programmed using
Computer Setup (BIOS), or by
changing the Microsoft®
Windows date & time.
This memory is not write-
protected.
Controller (NIC)
EEPROM
64 KB (not
customer
accessible)
No Yes Stores NIC
conguration
and NIC
rmware.
NIC EEPROM is programmed
using a utility from the NIC
vendor that can be run from
DOS.
A utility must be used to
write data to this memory
and is available from the
NIC vendor. Writing data
to this ROM in an
inappropriate manner will
render the NIC non-
functional.
DIMM Serial
Presence Detect
(SPD)
conguration data
256 bytes per
memory
module, 128
bytes
programmable
(not customer
accessible)
No Yes Stores memory
module
information.
DIMM SPD is programmed by
the memory vendor.
Data cannot be written to
this memory when the
module is installed in a
computer. The specic
write-protection method
varies by memory vendor.
System BIOS 9 MB Yes Yes Stores system
BIOS code and
computer
conguration
data.
System BIOS code is
programmed at the factory.
Code is updated when the
system BIOS is updated.
Conguration data and
settings are entered using
the Computer Setup (BIOS) or
a custom utility.
NOTE: Writing data to
this ROM in an
inappropriate manner can
render the computer non-
functional.
A utility must be used for
writing data to this
memory and is available
on the HP website; go to
http://www.hp.com/
172 Chapter 14 Statement of memory volatility