Sash

[Dave Olson]

In <daj.656899089 at godzilla> daj@ (Dean A. Jones) writes:

| I'm having a bit of trouble understanding what sash does. i.e. what is it
| really useful for, under what circumstances is it loaded etc. Any help would
| be appreciated.

sash (Stand Alone SHell) is used to load /unix, and other
'standalone' programs from the filesystem.  The PROM only
understands the special (i.e., simple) volume-header and
tapedirectory 'filesystems'.  For systems with newer PROMs
(almost all 4D's, except for the 4D60, and possibly a few
other older systems), when the system is set to autoboot,
the PROM loads sash automatically, and sash loads the file
listed in the volume header as the boot file.  This file
is most commonly unix, but could conceivably be other programs.

The other thing sash is commonly used for is to load the
standalone fx program from /stand/fx.   When you say:
	boot somefile (e.g., boot dksc(0,1,0)stand/fx)
to the PROM, it first loads the program listed in the NVRAM
environment variable 'bootfile', which is typically dkip(0,0,8)sash
for ESDI drives, and dksc(0,1,8)sash for SCSI drives; that program
is passed the remaining arguments, and tries to load that file.

Finally, if you have a PI, or a newer 4D[23]X0, then the 'install'
menu choice invokes sash -m, which looks for an installation
device, and if found, tries to load the miniroot from it, and
then load the appropriate kernel from the miniroot.  (Actually,
sash.IP6, sash.IP5, or sash.IP4 is normally what is loaded in this
case, depending on machine type).

I don't think we have much documentation on the standalone
environment available...
--

	Dave Olson

Life would be so much easier if we could just look at the source code.