HP ProBook x360 Maintenance and Service Guide - Page 81

Nonvolatile memory usage

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Nonvolatile memory usage Use this table to troubleshooting nonvolatile memory usage. Table 10-1 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 How is data entered into this How is this memory memory? memory? write-protected? HP Sure Start flash 8 MB (select models only) No Yes Provides Data cannot be written to this This memory is protected protected device via the host processor. by the HP Sure Start backup of The content is managed Embedded Controller. critical System solely by the HP Sure Start BIOS code, EC Embedded Controller. firmware, and critical computer configuration data for select platforms that support HP Sure Start. For more information, see Using HP Sure Start (select products only) on page 76. Real Time Clock 256 bytes No Yes Stores system RTC battery backed-up CMOS This memory is not write- (RTC) battery date and time is programmed using protected. backed-up CMOS and noncritical Computer Setup (BIOS), or by configuration data. changing the Windows date & memory time. Controller (NIC) 64 KB (not No Yes Stores NIC NIC EEPROM is programmed A utility must be used to EEPROM customer configuration using a utility from the NIC write data to this memory accessible) and NIC vendor that can be run from and is available from the firmware. DOS. NIC vendor. Writing data to this ROM in an inappropriate manner will render the NIC non- functional. DIMM Serial 256 bytes per No Yes Stores memory DIMM SPD is programmed by Data cannot be written to Presence Detect memory module the memory vendor. this memory when the (SPD) module, 128 information. module is installed in a configuration data bytes computer. The specific programmable write-protection method (not customer varies by memory vendor. accessible) System BIOS 9 MB Yes Yes Stores system BIOS code and computer configuration data. System BIOS code is programmed at the factory. Code is updated when the system BIOS is updated. Configuration 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 nonfunctional. A utility must be used for writing data to this memory and is available Nonvolatile memory usage 73

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Nonvolatile memory usage
Use this table to troubleshooting nonvolatile memory usage.
Table 10-1
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
flash
(select models
only)
8 MB
No
Yes
Provides
protected
backup of
critical System
BIOS code, EC
firmware,
and
critical
computer
configuration
data for select
platforms that
support HP
Sure Start.
For more
information,
see
Using HP
Sure Start
(select products
only)
on page
76
.
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
configuration
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 Windows date &
time.
This memory is not write-
protected.
Controller (NIC)
EEPROM
64 KB (not
customer
accessible)
No
Yes
Stores NIC
configuration
and NIC
firmware.
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)
configuration
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
specific
write-protection method
varies by memory vendor.
System BIOS
9 MB
Yes
Yes
Stores system
BIOS code and
computer
configuration
data.
System BIOS code is
programmed at the factory.
Code is updated when the
system BIOS is updated.
Configuration
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
Nonvolatile memory usage
73