Aucbvax.5449
fa.info-vax
utzoo!decvax!ucbvax!info-vax
Fri Dec 11 18:38:56 1981
IBM tape
>From alice!ark@Berkeley Fri Dec 11 18:32:24 1981

In reply to the message from "Lars.Ericson@CMU-10A": a tape that is
described by "DCB=(LRECL=80,RECFM=FB,BLKSIZE=3920)" is in the following
format:  It is probably in EBCDIC, presumably written by an IBM system.
The data should be considered to be divided into logical records of
exactly 80 characters each.  These logical records are collected into
blocks (physical records), each containing an integral number of
logical records, with no delimiters other than the known length of
a logical record.  No block is longer than 3920 bytes, hence 49
logical records.  If the tape is labelled by IBM standards (likely),
the first file will be a header label, the second file will be data,
the third file will be a trailer label, and so on.  In other words,
data reside on files numbered 2, 5, 8, ...  The whole tape ends with
two tape marks in a row.