HP 3000 Manuals

System Startup, Configuration, and Shutdown Reference Manual

Reading Stable Storage Contents 

Stable storage contains the boot path information along with other
critical file system parameters in a minimum area of 96 bytes of
high-reliability memory.  The storage maintains the critical parameters
even if the storage card is removed from the backplane.  After the
initial memory controller is initialized, the processor-dependent code
(PDC) accesses stable storage to determine the boot device and console
selection process.

The stable storage contents are allocated as shown in the following
figure.


          Figure C-1.  Stable Storage Contents 


NOTE  Byte addresses are numbered beginning with 0.  For example, 0 is
      the first byte, 1 is the second.


Decimal byte address 0 contains the status of the autoboot and autosearch
flags.  The byte contains two hexadecimal values.  The first two binary
digits of the first value show the flag status as either ON (1) or OFF
(0).  Byte 7, obtained by reading decimal address 4, contains the logical
module index.

The console path and alternate paths are stored in the same format as the
primary boot path.  Unlike the primary boot path, the first byte of the
first word of the console and alternate boot paths is set to hex 00.  The
autoboot and autosearch flags are not stored with these paths.

To read one word (4 bytes) of stable storage, use the ISL command READSS:

     ISL> READSS x Return 

or

     ISL> READSS Return 

           Input SS address: 4 

           Address 4 contains 0xFFFFFF08

In the last byte (number 7), 08 indicates the module number, 8.

MPE/iX 5.0 Documentation