wjm 19-aug-1997: PK2KDRVR & assorted patches to system programs, V1.2

Changes over initial version: Add fixes, plus one more check, for several 
				cases of bad register usage in PKNDRIVER.

	*** This is for VMS V5.5-2 only ***

PK2KDRVR is a driver for the Vs2000/uVAX2000 SCSI port
(traditionally known as the "tape controller port").

	>>> EXPERIMENTAL software, NO WARRANTIES at all! <<<

Apart from the restriction mentioned next, it _ought_
to behave just like the Vs3100 SCSI driver (PKNDRIVER);
the SCSI host adapter will have SCSI id 0 (not 6 or 7!).

Known restriction:
	PK2KDRVR won't do data transfers of 16kB or more.

	This has the effect of limiting the block size
	that can be used with SCSI tapes, and also will
	break any program that _attempts_ to read 16kB or more.
	The only VMS program that does so (which I'm aware of)
	is DUMP - see below for a patch.


Disclaimer:
	This is *EXPERIMENTAL* SOFTWARE that theoretically
	*could* not only crash your system, but *could* cause
	CORRUPTION on all media connected to the computer on 
	which it's installed.
	(In fact, PK2KDRVR has plenty of code that *attempts*
	to crash the system if a chance for corruption gets
	noticed, but the Vs2000/uVAX2000 hardware has never
	been "qualified" by anyone to work correctly with
	SCSI devices.)

	>>> NO WARRANTIES at all! <<<


Installation & use:

	*** This is for VMS V5.5-2 only ***

	The "binary kit" contains PK2KDRVR.EXE (not spelled PK2KDRIVER
	for quite "technical" reasons) plus 5 patch command files.

	Place PK2KDRVR.EXE in SYS$LOADABLE_IMAGES.

	Use
		$ PATCH @2KSYSGEN.COM
	to create 2KSYSGEN.EXE in the current directory.

	>>> Make sure that no MUA0 shows up, and that TVDRIVER
	>>> (the Vs2000/uVAX2000 magtape driver) is _not_ loaded.

	>>> NOTE that the SCSI host adapter has the SCSI id 0
	>>> (quite different from standard assignement of 6 or 7).

	Use
		$ MCR [dir]2KSYSGEN AUTOCONFIGURE ALL
	to load PK2KDRVR (ought to show up as device PKA0)
	and autoconfigure the SCSI devices, just like on a Vs3100.

	If you're confident enough in the driver that you want
	the machine to auto-configure the SCSI at boot time,
	create two more programs (which _may_ only be required
	if the machine is a cluster member),

		2KSTACONFIG.EXE via $ PATCH @2KSTACONFIG.COM
	plus	2KCONFIGURE.EXE via $ PATCH @2KCONFIGURE.COM

	and copy
		2KSYSGEN.EXE to SYS$SYSTEM:SYSGEN.EXE
		2KSTACONFIG.EXE to SYS$SYSTEM:STACONFIG.EXE
		2KCONFIGURE.EXE to SYS$SYSTEM:CONFIGURE.EXE

	Each of these programs supposedly behaves just like
	the VMS "original", when executed on a VAX other than
	a Vs2000 or uVAX2000.


	For completeness' sake, there are two more patch command
	files that create PK2K-aware versions of STASYSGEN.EXE and
	STANDCONF.EXE . Both of these are only used by stand-alone
	BACKUP - in order to build a PK2K-aware kit, place the
	patched programs into SYS$SYSTEM under the original name,
	and modify SYS$UPDATE:STABACKIT-TABLE.DAT by replacing
	"TVDRIVER.EXE" with "PK2KDRVR.EXE". You may also wish to
	change STABACKIT.COM such that it accepts generic SCSI tape
	(devtype 28) and on that occasion make it refer to a differently
	named *-TABLE.DAT - I did find a non-DEC DAT drive from which
	a Vs2000 did boot, with the tape configured as MKA100.
	

	Lastly, there's 2KDUMP.COM which will create 2KDUMP.EXE
	via	$ PATCH @2KDUMP.COM

	Use the result instead of the original SYS$SYSTEM:DUMP.EXE
	in order to DUMP blocks from a SCSI tape drive, e.g. via

		$ DEFINE/USER DUMP dev:[dir]2KDUMP.EXE
		$ DUMP MKAu00:

	or similar. Contrary to standard DUMP, 2KDUMP will - independent of
	hardware - read at most 16k-1 bytes per tape block (no big deal :-).


Wolfgang J. Moeller, <moeller@gwdg.de>