VBORMC::"asporner@eagle.ibc.edu" "Andy Sporner"  wrote:

>I bought a Quantum LPS-340 (thinking like an idiot that since somehow
>DEC and
>quantum were close somehow that it would work).  In order for VMS to
>format it,
>I had to send an ANSI command to the drive to turn off
>write-preallocation.  I
>don't know at what level this comes into play for NetBSD.  It seems like
>I had 
>trouble with (test 71) formatting it until I did this.

I know that VMS V5.5-2 and before had problems with certain (usually older)
drives that interpreted the SCSI spec differently. VMS is now (V7.1) much
more tolerant, although you may still find some tweaks required for
certain drives. I would expect most stuff to work though.

>Otherwise like the other guy said, stay below the size limitation.  I
>only would
>question this in the sense that VMS won't *BOOT* anything larger than
>2GB, but 
>it is said that you can have a *DATA* disk that is larger.  Since most
>ROM routines
>are generic, I would venture a guess that the 2GB thing might be tied to
>VMS.

VMS will boot off drives of virtually any size (well, pre V6.x it was 8.5GB
but now it is in the TB range ... should be good for about another year
or so at the current rate of SCSI drive capacity increase!).

However, the boot ROMS on all the VAXstation 3100 machines and on the MicroVAX
and VAXserver 3100 Model 10/20 machine (KA41-A,KA41-B) use 6-byte  SCSI
commands when reading and writing disk. This means any attempts to access
beyond 1.073GB or so "wrap around", which is not too cool. The MicroVAX and
VAXserver 3100 Model 10e/20e (KA41-D,KA41-E) ROMS (and all later machines
AFAIK) were updated to use 10-byte SCSI commands.

VMS uses this ROM code for booting (obviously) and for writing crash dumps, so
the system disk should be below 1.073GB in size unless you are willing to play
dangerous games with VDDRIVER to partition the disk. Data disks can be any size
you happen to have.

NetBSD can (I am told) avoid the problem because it is possible to ensure that
all the boot files live in the first 1GB of logical blocks.

Antonio


Antonio Carlini                            Mail: carlini@marvin.enet.dec.com
DECnet-Plus for OpenVMS Engineering
Digital Equipment Corporation              Worton Grange, Reading, England
                     (Reply-To: address mangled in header)