[Simh] Imaging SCSI HD's

[Clem Cole]

I love Mark's solution in the theory, but the systems I have that continue
to have solid SCSI support don't have a copy of simh, nor enough local disk
for the output.   What I have done in the past is something on the order of:

        dd if=/dev/RSCSI_DISK ibs=VERY_LARGE obs=4k conv=sync | ssh
remote_sys dd of=/tmp/vdisk.dsk ibs=4k obs=VERY_LARGE

The reason for the obs=4k is to keep the network block size under control.
 Depending on source and destination.   Blocking then becomes what is right
for the system (on something like a Vax or early x86 based bus maps, they
can only do 64K bytes of DMA at a time even if the host has more memory, so
even if you put a larger block, it's not clear you will get much more speed
up, and the OS how to clear our memory for the I/O, so it becomes a trade
off -- i.e. YMMV)

Now I have a/couple of different version(s) of dd I dug up/rewrote years
ago called ddd - double dd  (before gnu's Debugger existed BTW).  The
original ddd used to UNIX processes the swap back and forth controlled via
a pipe (you can find it in the UUNET archives I want to say around 1985),
but my newer versions used can use threads of some sort if the local UNIX
supports MxN user mode threading, or async I/O is that was supported as the
threading overlap tends to be more efficient in the kernel itself, but the
idea is the same - you want as much I/O overlapped as possible.   [I
originally did this to fully stream tape drives in the bad old days of a
10Mhz 68000 are the processor.  We ran:  dump -f - | ddd of=/dev/rmt0
ibs=20b obs=64k ].


ᐧ

On Sun, Apr 21, 2019 at 5:37 PM Mark Pizzolato <Mark at infocomm.com> wrote:

> On Sunday, April 21, 2019 at 11:28 AM, Zane Healy wrote:
> > I have a DL380 on the way to add to my ESXI cluster here at home.  As a
> result
> > I’m looking to finish virtualizing my DEC HW.  What is the best way to
> convert
> > a physical SCSI HD to a disk image for SIMH?  I need to do this for both
> VAX
> > and PDP-11.
>
> If these are SCSI disks, AND you have a host system with a SCSI host
> adapter
> that can connect to these disks (i.e. it is the correct SCSI width, and
> type),
> then you can do this directly using simh from the host system.
>
> Warning: If  you try to do this under some complicated set of layered
> virtual systems, then you are on your own (recall your VNC experience).
>
> Depending on your host system the OS will have some name for the
> above mentioned SCSI disk(s) which you've connected.
> When you connect these disks to the host system, BE SURE not to
> perform any action on these drives BEFORE you let simh see them.
> Be sure you identify the raw device name that the OS sees the newly
> connected SCSI disks as.  Knowing that name the following should work
> with a VAX or PDP11 simulator.  Note that this will probably have to
> be done as root in order to access the physical devices.
>
>        # vax
>        sim> ATTACH RQ0 -c <rawdevicename> disk1.vhd
>        sim> DETACH RQ0
>
> This will produce a "disk1.vhd" container file with all of the bits that
> can be read from the original SCSI disk.
> Repeat as necessary for each original disk.
>
> > One of the main systems that I want to Virtualize is a VAXstation 4000/60
> > with a BA350 shelf.  The only HD connected to the system is a RZ28-VA SBB
> > (2GB) as DKA200:, so yesterday I added a RZ29-VA SBB (4GB) as DKA100:.  I
> > setup Standalone Backup on the RZ29 and booted into Standalone backup.
> >
> > I tried to run the following:
> > backup/image/verify dka200: dka100:[000000]20190420-system.sav/sav
> >
> > I ended up with a very strange “No valid storage bitmap found” error,
> and it
> > failed to copy anything.
> >
> > Facility: BACKUP, Backup Utility
> > Explanation: Software bad block data is not present on the volume. The
> > volume has been initialized with no bad blocks.
> > User Action: Execute the Bad Block Locator utility before using the
> volume.
> > NOBITMAP, no valid storage bitmap found on 'device-name’
> >
> > I tried ANALYZE/MEDIA, but may not have been doing things right.  This
> is a
> > Genuine RZ29-VA, but it was originally used as part of a disk array for
> a Sun
> > Sparc system.
>
> This exercise will merely put a backup saveset on another disk which I
> don't
> see getting you very far towards making it accessible from simh.
>
> Meanwhile, I suspect you are seeing a failure under standalone backup due
> to the fact that after you added the DKA100 disk drive to the system you
> didn't initialize the disk.  You can't initialize a target disk under
> standalone
> backup, so you'll have to do that with full VMS running before you attempt
> the backup again.
>
> - Mark
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