And it is DSC2, not VMS Backup that is used for the restore, since V1.x
distros were in that format.
/Wilm
Johnny Billquist schreef op 6-11-2017 om 01:19:
On 2017-11-06 00:39, Paul Koning wrote:
On Nov 5, 2017, at 5:48 PM, Johnny Billquist <b...@softjar.se> wrote:
Ah.
That sound like a simh problem. The tape file itself have one of a
few different formats, none of them even keep any CRC (at least none
of the ones I can think of right now).
The backing file storage just have the tape records. And obviously,
since the same backing file storage is used on both emulated tape
drives, there is obviously nothing wrong with the file.
Any CRC indication is purely made up in simh. And that is where you
get the error indication. So I guess someone needs to dig into the
emulation of the Massbus tape drives.
Another possibility: VMS BACKUP has its own CRC in its data blocks,
entirely separate from the tape drive hardware check codes. If
BACKUP reports CRC errors, it's most likely talking about those.
BACKUP also writes redundant blocks, so if only 1 out of N blocks is
bad, the bad block can be reconstructed. Presumably, CRC errors
reported by BACKUP are caused by flaws in the original material that
was transcribed into SIMH tape images.
...in which case it should show up both using the TS11 and TE15. But
it only shows up in the TE16, which suggests that there is nothing
wrong with the contents of the actual tape image file.
Correct me if I'm thinking wrong somewhere here.
Johnny
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