14 Mar
2005
14 Mar
'05
6:39 p.m.
Hi everyone,
Well, I am finally getting around to trying to recover some 26
9-track tapes I have been holding on to for
at least 10 years. Some are closer to 25 years. I found out six of
them had no data, and a bunch more I
have been able to read and decode, including some RT-11 tapes and some
VAX SIG tapes. Sorry this
monologue won't make much sense to you non-DEC folks, but you might have
ideas on converting from 800
to 1600 BPI anyway.
Here is my dilemna. I have 6 tapes that look like they are 800 BPI, and
were most likely written on an RSX-11
system. I have no 800 BPI setup, and if I did, it would be on a VAX,
which may not be able to restore the
savesets anyway. That is because I have a few more tapes that I can
read (or at least dump) but I cannot unpack
the savesets. It would appear that the tapes were written in the early
days of VMS when the backup and restore
utilities were really RSX-11 BCK/RST derivitives, and the current BACKUP
program does not recognize
the container file as a valid saveset.
The label on the front of several tapes date them early 80's and talks
about BCK format. The dump sort of looks
like BCK stuff. The blocksize is 2064.
I've had a couple of offers to try to recover the data, but I was
checking to see if anybody was set up to easily
read and recover the data, without a lot of reconfiguration or hassle.
I'm open to suggestions. I suspect if I knew
the layout of a BCK container/saveset I could unpack them myself (except
for the 800 BPI stuff). Any ideas??
I also have an XXDP tape, labeled MSDP, which makes me think it is
bootable. It would be nice to duplicate
it, as it is not easily read to disk. The first block is 14 bytes, and
the rest look like 512 bytes.
And finally, I have a tape that is readable, is mountable under VMS and
I can copy nearly everything off of.
That is, the 400+ files up to the file that is marked HECK.BCK. That
file is 2064 byte blocks, which makes
me think it is also a BCK/RST format. Can't figure how I got it on the
end of the tape and haven't figured
out how to get it back.
Cheers,
Joe Heck
15 Mar
15 Mar
6:59 a.m.
>>>> "joe" == joe heck <trash3
at splab.cas.neu.edu> writes:
joe> Here is my dilemna. I have 6 tapes that look like they are 800
joe> BPI, and were most likely written on an RSX-11 system. I have
joe> no 800 BPI setup, and if I did, it would be on a VAX, which may
joe> not be able to restore the savesets anyway. That is because I
joe> have a few more tapes that I can read (or at least dump) but I
joe> cannot unpack the savesets. ...
Could you read them as straight streams of blocks, and produce a .TAP
file from that, which you can then feed to RSX running in an emulator?
Or write the data back out to another tape at a density that your RSX
system supports?
joe> I also have an XXDP tape, labeled MSDP, which makes me think it
joe> is bootable. It would be nice to duplicate it, as it is not
joe> easily read to disk. The first block is 14 bytes, and the rest
joe> look like 512 bytes.
That's a DOS format tape -- the 14 byte record is the file label. If
it's bootable, then the next block is the boot program. You could
read it and see if it looks like PDP11 code. A boot block would
typically have either reset (5) or NOP (0240) in the first word.
paul
3:21 p.m.
Yes, Paul, it has the 240 opcode in the right place. And I remember the
MSDP tapes being bootable. But I have no
way of making a copy of it, unless I mounted it wrong. EXCHANGE didn't
recognize it as
DOS-11, but I'll try again. If that works, then I should be able to
read it in and write it back out to another tape.
(and make a copy on the hard drive) Thanks for the insight.
The problem with the BCK files is that they come in as 2064 byte blocks
from the tape and VMS gets
really upset when I
try to write them to the disk. Haven't figured out
how to deblock them enough to
get them on to the system. The interesting part is that I would have
expected them to be 2048 (512*4)
but there is either a 16 byte header on each block, or each 512 byte
record has 4 bytes (Integer) in the
front for recordsize (something RMS would have stuck on there).
And finally, yes, the first step for the (6) 800 BPI tapes is to ditto
them to other tapes at 1600 BPI.
Paul Koning wrote:
>>>>
>>>>
Could you read them as straight streams of blocks, and produce a
.TAP
file from that, which you can then feed to RSX running in an emulator?
Or write the data back out to another tape at a density that your RSX
system supports?
That's a DOS format tape -- the 14 byte record is the file label. If
it's bootable, then the next block is the boot program. You could
read it and see if it looks like PDP11 code. A boot block would
typically have either reset (5) or NOP (0240) in the first word.
paul
16 Mar
16 Mar
6:27 a.m.
>>>> "joe" == joe heck <trash3
at splab.cas.neu.edu> writes:
joe> The problem with the BCK files is that they come in as 2064 byte
joe> blocks from the tape and VMS gets really upset when I try to
joe> write them to the disk. Haven't figured out how to deblock them
joe> enough to get them on to the system.
Strange. You shouldn't need to. If you tell RMS that you want fixed
length records, length 2064, "spanned", it should accept what you have
just fine. Or convert them to TAP format before writing them to
disk...
paul
18 Mar
18 Mar
6:06 a.m.
Hi Joe,
I have an 800/1600/6250 bpi HP SCSI tape drive on a Sun system. I have the
tape image tools on the server so I can make PDP10 boot tapes. I should be
able to make *.TAP images of your tapes.
At 09:39 PM 3/14/2005 -0500, you wrote:
Hi everyone,
Well, I am finally getting around to trying to recover some 26
9-track tapes I have been holding on to for
at least 10 years. Some are closer to 25 years. I found out six of
them had no data, and a bunch more I
have been able to read and decode, including some RT-11 tapes and some
VAX SIG tapes. Sorry this
monologue won't make much sense to you non-DEC folks, but you might have
ideas on converting from 800
to 1600 BPI anyway.
Here is my dilemna. I have 6 tapes that look like they are 800 BPI, and
were most likely written on an RSX-11
system. I have no 800 BPI setup, and if I did, it would be on a VAX,
which may not be able to restore the
savesets anyway. That is because I have a few more tapes that I can
read (or at least dump) but I cannot unpack
the savesets. It would appear that the tapes were written in the early
days of VMS when the backup and restore
utilities were really RSX-11 BCK/RST derivitives, and the current BACKUP
program does not recognize
the container file as a valid saveset.
The label on the front of several tapes date them early 80's and talks
about BCK format. The dump sort of looks
like BCK stuff. The blocksize is 2064.
I've had a couple of offers to try to recover the data, but I was
checking to see if anybody was set up to easily
read and recover the data, without a lot of reconfiguration or hassle.
I'm open to suggestions. I suspect if I knew
the layout of a BCK container/saveset I could unpack them myself (except
for the 800 BPI stuff). Any ideas??
I also have an XXDP tape, labeled MSDP, which makes me think it is
bootable. It would be nice to duplicate
it, as it is not easily read to disk. The first block is 14 bytes, and
the rest look like 512 bytes.
And finally, I have a tape that is readable, is mountable under VMS and
I can copy nearly everything off of.
That is, the 400+ files up to the file that is marked HECK.BCK. That
file is 2064 byte blocks, which makes
me think it is also a BCK/RST format. Can't figure how I got it on the
end of the tape and haven't figured
out how to get it back.
Cheers,
Joe Heck
Michael Thompson
E-Mail: M_Thompson at IDS.net
7220
days inactive
7223
days old
4 comments
3 participants
participants (3)
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m_thompson＠ids.net -
pkoning＠equallogic.com -
trash3＠splab.cas.neu.edu