Recovering data from 4mm and 8mm tapes

[Nico de Jong]

----- Original Message ----- 
From: "Douglas Taylor" <dj.taylor4 at verizon.net>
To: <General at classiccmp.org>; "Discussion at classiccmp.org:On-Topic Posts" 
<cctech at classiccmp.org>
Sent: Monday, March 23, 2015 4:46 PM
Subject: Recovering data from 4mm and 8mm tapes


> I have a couple of 4mm and 8mm tapes that contain data I want to recover. 
> The 4mm is DDS-1 and was written using tar on a SGI system in 1998.  My 
> questions are;
>
>  'What modern DAT tape drive will read this tape?  How backward compatible 
> is this technology?'
>
> The 8mm tapes were also written on an SGI system, however it was in 1994 
> and the IRIX Backup utility was used.  IRIX 5 was probably used.  Any 
> ideas?

DDS-1 can normally be read on DDS-2, in my experience. I seem to remember 
that Sony and HP DDS drives of that generation are not totally 
interchangeable, especially for the compression routines. But I might 
confuse it with some other system.
Are the 8 mm tapes Exabyte format? Exabyte drives are normally 1 or 2 
versions upwards compatible, so you can read 8200 tapes on 8500 drives, but 
probably not on Eliant drives, etc.
I have now idea on how IRIX handled the backup.

/Nico