Checking Contents of Unknown Disks

27 Apr 2014

...

 On 04/26/2014 03:21 PM, Robert Jarratt wrote:
  I have some SCSI disks with unknown contents
which I would like to
 check before overwriting them. I don't even know what OS they were
 used with. The only systems I have to hand with SCSI are MicroVAXen,
 so I can check them for VMS format without issue. However, for the
 ones that are not VMS format I would need a way to find out what format  they are.

 I don't know what facilities VMS gives you, but I normally drag the first 
block
  off an unknown disk and just look at it in a hex
editor. 
 Actually, it shouldn't be too hard to write the code to read the raw blocks
 off a disk in VMS. I think I will do it as an exercise as it should be fun
 and a chance to remember how to program on VMS again.

You don't have to do that.

$ MOUNT /FOREIGN disk:
$ DUMP disk: /BLOCK=START=n

will give you an ASCII and hex dump of the disk starting at block n (assuming
the disk has 512 byte blocks).

Do not omit the colon at the end of the device name or VMS will think you
want to dump files instead.

Also, there was/is a utility called PCDISK (which came with Pathworks I think)
which allows PC format floppys to be read and written on VMS.  I think it was
also supposed to work with some subset of hard disks but I never managed to
get it to do that - I never tried very hard though.  IIRC there is a freeware
equivelant called MGPCX which might be more flexible.

Regards,
Peter Coghlan.

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Checking Contents of Unknown Disks