RS/6000 Tape questions

[Andreas Kaiser]

 >"smit" gives no information about choosing an error 
 >detection/correction

 >method. However, it does ask whether to use "extended file 
 >marks". The default appears to be "no"; should I change this to "yes"?
 >Is the problem simply that the file marks aren't long enough (?) for 
 >positioning 

I don't know about the changes in IBMs tape firmware but the mechanically identical tape Tandberg 3660 (and this magic name or number is written somewhere in the papers of the 6000) has no trouble writing at the end of the tape, when used with my own software under MSDOS. But it is not possible to overwrite existing tape data except at the beginning of the tape. There are just two places, where data can be written: at the beginning and the so-called "logical end of tape".

And there is another (but nonstandard) feature missing in the 6000's software: Direct tape positioning. The Tandberg tape can be commanded to directly position to a given block number, which is done using an efficient seeking algorithm and takes at most two track times (~30 seconds to ~4 minutes). This is a really nice feature, when it comes to restore a single file from a full archive tape (~15 seconds to ~30 minutes).

                Gruss, Andreas

 * Origin: kaiser at ananke.stgt.sub.org - Stuttgart FRG (2:244/7014)