Quick test. Copy the tape into disk files using both drives, then compare the
two files. If they come out the same, then it's something in backup. If they're
different, you can look and see what bits are changed. If copy errors out on
the team, then that's probably simpler to debug than backup.
Btw. Does anyone have a source for ds10l cup fans? I need to replace a very
noisy onr.
Sent from my Galaxy Tab® A
-------- Original message --------From: Johnny Billquist <b...@softjar.se>
Date: 11/5/17 5:19 PM (GMT-07:00) To: Paul Koning <paulkon...@comcast.net>
Cc: simh@trailing-edge.com Subject: Re: [Simh] Simh Digest, Vol 166, Issue 12
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
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: b...@softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
_______________________________________________
Simh mailing list
Simh@trailing-edge.com
http://mailman.trailing-edge.com/mailman/listinfo/simh_______________________________________________
Simh mailing list
Simh@trailing-edge.com
http://mailman.trailing-edge.com/mailman/listinfo/simh
