Everhart,Glenn
From:	Everhart,Glenn
Sent:	Thursday, April 23, 1998 8:14 AM
To:	Info-VAX@Mvb.Saic.Com
Subject:	RE: VAXstation 3100 and SCSI-drive an VMS 5.4-1
The statement that VS3100s won't boot from disks larger than 1 gig isn't
quite true. What is true is that the boot code can only access about a
gig.

Thus to boot off larger disks the trick is to ensure the boot stuff is
all in the
first gig.

I've done this by booting off a small disk to get started (standalone
backup
won't support the /index=beg needed to do it cold, darn it!). (I suppose
the
boot-off-CD tricks mentioned in this list could be used too.)

Then I init the disk with /index=beg so the index file gets put at the
low blocks
on disk. THAT is vital; default is in the middle, and for disks much
above
2 gigs, it'll mean the index file can't be read by boot code.

Then I create large contiguous files enough to fill the disk, creating
one of
about a gig first (which gets deleted) and then one or more others to
take
up all remaining space on the disk. (I tend to use copy/contig/alloc but
other tools exist also. Files so created should be tagged /nomove.)

I delete the first one, and use the frag tool that comes with Juicer, or
some
other method, to be sure the disk now has the first gig free.

Now I take an /image backup of a bootable disk and do a NON-image
restore
onto the disk just created for it.

To make this usable, I need to create an alias such that
[sys0]syscommon.dir
is the same as [000000]vms$common.dir. I do this with set file/enter.

I then use [sys0.syscommon.sysexe]writeboot.exe to write a bootstrap
onto the
disk.

At this point it should be bootable. I've always used virtual disks and
vddriver
to use the rest of the space.

For this stragegy to work you need at least one 1GB disk available (even
if
it's off on a shelf most of the time) for emergencies, or to have tested
backup
operation off CD. You wind up with a system disk of 1GB and "other"
disks
that can be huge, but you can play this trick on every physical disk you
have.
I've also tended to add otherdisk:[sysexe2] to the sys$system:
searchlist
and moved as much as possible of layered stuff onto it. This game can
be carried on further, and Safety softlinks can be used to also move
things
off the system disk invisibly. You just MUST be careful that nothing
that is
needed at boot is moved off.

I've always felt safer on a VS3100 when I had at least two disks that
could
be booted. That way if I screw one up, I can boot the other and recover.
Do likewise.


> -----Original Message-----
> From:	David Lewis [SMTP:DLewis@mits.com.au]
> Sent:	Wednesday, April 22, 1998 6:22 PM
> To:	Info-VAX@Mvb.Saic.Com
> Subject:	Re: VAXstation 3100 and SCSI-drive an VMS 5.4-1
> 
> 
> 
> Ferry Bolhar-Nordenkampf wrote:
> 
> > Scotty wrote:
> > >
> > > Some very old VaxStations are unable to boot from disks larger
> than 1 gig.
> > > This problem is a limitation from the hardware and I don't know of
> any
> > > workaround. MicroVax 3100's do NOT suffer from this limitation.
> >
> > That's not completly correct - the first MicroVAX 3100 systems
> suffer as
> > well (we had some of them). The difference is that there were
> firmware
> > (ROM) replacements for the MicroVAX 3100 to solve this problem, but
> > there were never any replacements for the VAXstation 3100.
> >
> > Greetings, Ferry
> >
> 
> It's a shame, really - it limits the life of these machines.  They may
> not be
> too quick, but they work well enough for me.  The only problem is the
> availability of 1GB disks.  All I ever see in ads these days is 4GB
> and greater.
> 
> How much more difficult would it have been to create an updated PROM
> for the
> VAXstation than it was for the MicroVAX?
> 
> On the other hand, does the VAXstation 4000/VLC suffer from the same
> problem?
> 
> > --
> > Ing. Ferry Bolhár-Nordenkampf
> > Magistrat der Stadt Wien (MA-14)        A - 1010 Vienna (Austria)
> > Phone: +43 1 4000 98632                 E-Mail:
> bol@adv.magwien.gv.at
> >
> > "Wenn hier einer schuld ist, dann immer nur der Computer."
> 
> --
> David Lewis,
> MITS Real Time,
> MITS Limited, Australia.         Phone:  +61 3 9872 6039
> Internet:  DLewis@mits.com.au    Fax:    +61 3 9874 6940
>