System Startup, Configuration, and Shutdown Reference Manual (32650-90907)

Chapter 3
System Startup Functions
Reading Nonvolatile Memory (NVM)
53
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 to produce the local time, displayed on
the console.
To read or set the hardware clock, enter:
ISL> clkutil
The system responds with the following banner:
SYSTEM FOR ISL STAND ALONE UTILITIES. [IHO, SPU LAB]
Version 1.0