🚀 go-pugleaf

In article <2rg6f1$63v@netnews.upenn.edu>,
Kirsten Starcher <kirsten@econ.sas.upenn.edu> wrote:
>We have decided, for the time being, to treat labelled tapes and 
>unlabelled tapes identically, ... i.e. the header and trailer labels on 
>the tapes will just be copied as individual files.  So what we think we'll 
>need to do is this:
>
>  for each physical file on the 9-track tape, make a file on our output
>      medium of choice.
>
>  for each block in each file
>     read the block with no translation or truncation.
>
>     measure the length of the block
>
>     write an output record composed of the concatenation of
>      - a 2 byte integer equal to the input block length plus 2
>      - the untranslated input block
>
>     (i.e. we're imitating how the IBM mainframe does variable length
>      records).
>
>Then later we can deal with data translation issues.
>
>We were hoping somebody who reads this request might have already dealt 
>with this problem.
>
>
>kirsten@ssc.sas.upenn.edu
>

There are a number of people that have used exactly this code block to
duplicate tapes on unix systems with one tape and lots of disk.

I've written it several times ... a simple half page C program (if the
9trk driver is reasonable). You will find it valuable to make the first
segment of each "virtual tape" file a manual transcription of the physical
human readable label on the tape since even the IBM/ANSI labels give
little clue as to the real contents in many cases. Use more than 16bits
for length ... there are many tapes with blocks much longer. Most drive
and formatter manufacturers ignored the limited max block length in the
ANSI spec.

John