[TUHS] Someone wants to use an exabyte

John Foust jfoust at threedee.com
Thu Nov 28 05:31:11 AEST 2019

At 04:52 PM 11/24/2019, Larry McVoy wrote:
>Good luck with that.  I had a 4/470 that had an exabyte, wheeled it out of
>building 5 at Sun and into building 9 at SGI and the tapes wouldn't read

I jumped in on that Twitter thread when I saw it.

Two years ago or so, I attempted to read a couple dozen old backup tapes from the mid 1990s. Half were Archive Python DDS-2 era, written on two different drives that I still had, as 'tar' tapes from SGI workstations. The other half were Exabyte 8500 8mm, some 'tar' from SGI and Linux and Amiga, some 
Windows NTBACKUP.  I set up a fresh Linux box with an Adaptec SCSI card.

I couldn't get any of the DDS-2 to read, either on the original hardware that wrote them, or on a newer STD28000N drive I bought on eBay, a pull from an old Apple server. I could write new tapes on the drive, just couldn't read any old ones. My attempts included reading some tapes I know I'd received from other people (that is, written on other drives) that I know I had been able to read on this hardware back in the day. They wouldn't read, either.

On the other hand, I could read the majority of the Exabytes, even on the original drive I had retained, as well as another I'd bought used in the early 2000s. Some had bad blocks here and there.

The tougher task was trying to find contemporary tools that could process the data stream from an old NTBACKUP, especially a stream with corruption from missing chunks, as I wasn't in the mood to try to rebuild an NT machine with SCSI to let NTBACKUP deal with the drive directly, and I think it would probably fail harder on direct drive errors.

The Amiga-made 'tar' archives were readable by 'tar' but the file time stamps weren't right when burst under Linux. I didn't debug that yet.
- John

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