System Startup, Configuration, and Shutdown Reference Manual (32650-90892)

Chapter 3 57
System Startup Functions
Reading Nonvolatile Memory (NVM)
Reading Nonvolatile Memory (NVM)
NOTE Not available on N-Class and A-Class systems
Nonvolatile memory stores system activity parameters, including a circular queue of the
last six ISL utilities executed. This information remains intact, even through system
failures.
To read the contents of NVM, enter READNVM
nn at the prompt, where nn is the location to
be read:
ISL> READNVM 68
Address 68 contains 0x32363334
For information on the contents and locations of NVM, refer to Appendix C , “Reading
Stable Storage and Nonvolatile Memory.”
Reading Stable Storage
Stable storage stores boot path information along with other critical system parameters.
Like NVM, stable storage maintains its information through system crashes and failures.
Unlike NVM, stable storage maintains its information even if the memory card, containing
stable storage, is removed from the backplane.
To read the contents of stable storage, enter READSS
nn at the prompt, where nn is the
location to be read:
ISL> READSS 40
Address 40 contains 0XFFFFFFFF
For information on the contents and locations of stable storage, refer to Appendix C ,
“Reading Stable Storage and Nonvolatile Memory.”
Reading and Setting the Hardware Clock
The ISL utility CLKUTIL reads and sets the battery backed-up hardware clock. This clock
maintains Greenwich Mean Time (GMT) independently of the software clock that is
displayed when you enter the ISL START utility or any of the other ISL utilities that
support the software clock. (Refer to Example 3-7 for an example of the software clock
interaction.). The CLKUTIL utility, therefore, reads the date and time that were previously
set with CLKUTIL, but does not itself reflect the changes that you may make while in any
other ISL utility.
The hardware clock should be set to GMT if the clock displays are to be correct on the
booted system. The hardware clock provides the basis for time displays that are part of
some ISL utilities.
When the local time is entered during particular ISL utilities, the system computes an
offset and stores it in stable storage. During a boot, the GMT and this offset are combined