[Simh] SCSI-Interface for simh-vax?

[Paul Koning]

> On Sep 1, 2018, at 4:18 PM, Timothe Litt <litt at ieee.org> wrote:
> 
>> ...
> 
>> I wasn’t able to figure out how to make it work in RSTS/E.
> 
> To be bootable, a CD needs an appropriate boot block (LBN 0).  For VMS,
> it's written by 'writeboot' - not initialize.  I don't remember the
> details for RSTS - look at SAVRES->RESTORE and BACKUP for
> possibilities.    Or wait for Paul K to fill that in.
> 
> Also note that dual format CDROMs are possible - 9660 reserves the first
> 16 sectors for this; thus it's possible to write a disk that is readable
> as both FILES-11 and & 9660 (with file data being in the same sectors;
> only the metadata differs.)  Such disks were actually created.

More details for RSTS.

Right, when you initialize a RSTS disk it isn't bootable.  You get a dummy boot (one that prints "please boot from the system disk") instead.

Bootable disks are created in one of several ways.  SAVRES does, but that isn't helpful here.  The other is the HOOK utility, which should be on the RSTS kit.  The way that works: first make sure INIT.SYS has been copied into [0,1] on the destination device.  Then run HOOK and tell it: 

	dev:[0,1]

and that should be all you need.  (This is for disk; tape is different and I don't have the details handy.)

BACKUP doesn't create bootable devices.

Note that a bootable tape, and a bootable disk whose file system flags say it's read-only, are considered installation media.  Read/write bootable disks are considered a system disk.

Finally, yes, I remember working with Fred Knight on dual format RSTS/E CDROM.  The intent was to create a single disk with all RSTS/E DEC software on it.  I don't know if that ever happened; I never saw the results.  But to make this possible I added a mode to FLX to create a dual mode disk, ISO 9660 plus RSTS/E file system.  Look in the FLX 2.6 documentation, the "-merge" switch.  Note that I removed it from the FLX 3 code (Python based FLX), though it could be brought back easily enough.

	paul