Booting the Standalone Shell

Booting the Standalone Shell

The Command Monitor has been designed to keep it independent of operating systems and as small as possible. Therefore, the Command Monitor cannot directly boot files residing in IRIX or other operating system file trees. However, the Command Monitor does provide a two-level boot mechanism that lets it load an intermediary program that does understand file systems; this program can then find and load the desired boot file. The program is called the standalone shell, and is referred to as sash. sash is a reconfigured and expanded version of the Command Monitor program, and includes the modules needed to handle operating system file structures. It also has enhanced knowledge about devices.

After the system software is installed, a copy of sash is located in the volume header of the first disk. The header contains a very simple file structure that the Command Monitor understands. You can also boot sash from tape or across the network if need be. To boot sash from your disk, shut down the system, and when you see the message:

Starting up the system...

To perform system maintenance instead, press Esc

Press the escape key. You may have to enter your system's Command Monitor password, if your system has one. Next, you see a menu similar to the following:

System Maintenance Menu

(1) Start System

(2) Install System Software

(3) Run Diagnostics

(4) Recover System

(5) Enter Command Monitor Select option 5, ''Enter Command Monitor'' from the System Maintenance Menu. You see the following message and prompt:

Command Monitor. Type "exit" to return to the menu.
>>

To boot the standalone shell (sash), enter the command:

boot -f sash

sash operates in interactive command mode. You see the sash prompt:

sash:

To use the multi-level boot feature, set the PROM environment variable bootfile to refer to a specific copy of sash. In normal configurations, setting bootfile to dkip(0,0,8)sash tells the Command Monitor to load sash from the ESDI disk controller 0, disk unit 0, partition 8 (the volume header). Use this syntax:

ESDI drives: setenv bootfile "dkip(0)disk(0)partition(8)sash"
SCSI drives: setenv bootfile "scsi(0)disk(1)partition(8)sash"
SMD drives: setenv bootfile "xyl(0)disk(0)partition(8)sash"
IPI drives: setenv bootfile "ipi(0)disk(0)partition(8)sash"

Then issue a boot command, as in this example for an ESDI drive:

boot dkip()unix initstate=s

The following actions take place:

boot loads dkip(0)disk(0)partition(8)sash, as specified by bootfile, since the boot command doesn't contain a -f argument. (A -f argument would override the default specified by bootfile.)
sash gets two arguments: dkip()unix and initstate=s, which brings the IRIS up in single-user mode. (Note that the Command Monitor removes the leading hyphen [-] from any argument, so if you use the next layer of software, and need an argument with a leading hyphen, you should put two hyphens in front of it.)
sash loads the file specified by the first argument (dkip()unix) and passes the next argument to that file.

Do not issue the auto command from sash with the bootfile set as shown above. If you do, the system tries to boot sash over itself and will exit with an error.

To be able to use the auto command from sash, set bootfile to refer to the kernel, for example, dkip()unix. Even better, return to the PROM level to use the auto command.