>>Typical example for variable length records are ANSI format tapes.

>Ok, I got the picture. I would however bet a case of Diet Dr. Pepper that 
>the XXDP+ tape is a single, 512 byte block file that is bootable. With some 
>number of 512 byte blocked memory images (one per file) on the tape after 
>the "shell".

Nope, an XXDP+ tape has a format descended from DOS-11.  There's a
512-byte boot block, followed by a mix of short 14-byte (or 16-byte)
labels and 512-byte data records.

The field service diagnostics tape for a Microvax has 80-byte headers
and 512-byte data blocks interspersed with a whole lot of tape marks.

>But the point is moot if there is no tape to copy.

XXDP+ doesn't run on a Microvax - it runs on a PDP-11.

-- 
 Tim Shoppa                        Email: shoppa@trailing-edge.com
 Trailing Edge Technology          WWW:   http://www.trailing-edge.com/
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