dd-equivalent for VMS

Rob Jarratt robert.jarratt at ntlworld.com
Fri Jun 16 12:30:15 CDT 2017

I have had multiple interesting and useful answers. Thanks everyone.

I checked on VMS 7.3 and there is no COPY/IMAGE there. BACKUP/IMAGE had been my first thought, but it won't accept a tape as the source of the image data unfortunately.

I have a TZ30, so I will try that on Ultrix. I will also try a more recent Unix (Debian probably) on an Alpha and see if that can read from a later drive.

May last resort is to write my own VMS QIO-level program to read raw blocks myself.



> -----Original Message-----
> From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Robert
> DiRosario via cctalk
> Sent: 16 June 2017 15:28
> To: cctech at classiccmp.org
> Subject: Re: dd-equivalent for VMS
> You could remove the disk from your Ultrix box, install another diskand install
> NetBSD.  The Pmax version works on the DEC MIPS
> boxes:http://wiki.netbsd.org/ports/pmax/.  You could also do that on your
> DECAlpha.
> The TK50Z should be a SCSI drive, you could also just move the drive to another
> UNIX/Linux/BSD box
> It's been a while since I played with any of my vintage computers that have a
> TK50 drive.  Could it be that the SCSI controller / bus in the Ultrix box isn't fast
> enough to handle the tape drive at "full speed"?  You could try putting the drive
> on a modern computer with a modern SCSI controller with nothing else on that
> SCSI bus.
> Ten plus years ago I was working on a satellite ground system and we needed
> to record the real time down link so we could use it to test the system.  The
> data was written to a SCSI DLT drive.  The speeds listed for most tape drives are
> peak speeds, and it was very hard to get a sustained data rate that was close to
> the peak data rate listed by drive manufacturers.
> Robert
> --------------------------------------------------------
> Is there a dd equivalent for VMS?
> Background:
> I am trying to recover some TK50 tapes that were written on Ultrix.
> I have a MIPS machine with Ultrix 4.5 on it and a TK50Z drive. I have been able
> to read some tapes but they all seem to get an I/O error after a while of
> reading. I think this could be due to the accumulation of oxide on the heads.
> Despite cleaning the heads after every tape (by disassembly and cleaning with
> isopropyl on a cotton bud). I think the oxide is accumulating more than
> necessary because of the poor streaming abilities on the TK50 drive (too much
> back and forth over the same section of tape).
> I do have more modern drives (TK70, TZ85, TZ87 etc), but Ultrix does not seem
> to recognise them. So I was hoping to use one of my VAX or Alpha machines
> with VMS and a better tape drive to recover the raw data. Ideally I would like
> to make a SIMH virtual tape clone of the real tape.
> Any other alternative suggestions very welcome.

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