- DEC Binary (XXDP) file format

The DEC Binary (XXDP) format was used on the PDP 11 series machines. This is a binary format, and is not readable or editable with a text editor. The file consists of records of the form center,allbox,tab(;); l l l l l. type;length;address;...data...;checksum The field are defined as follows:

type

Two byte little-endian value. Must always be 1.

length

Two byte little-endian value. This is the number of bytes in the data, plus six.

address

Two byte little-endian value. This is the load address of the data.

data

The data is simple raw bytes. There are (length-6) of them.

checksum

The checcksum is a single byte. It is the negative of the simple summ of all the header and data bytes.

If the record length is exactly 6 (i.e. no data), this is the start address record, indicating the transfer address.

In addition there may be NUL padding characters between records. It is common for records to be padded so that they start on even byte boundaries. In the days of paper tape, it was common for the file to have many leading NULs, to generate blank leader on the tape.

Size Multiplier

version

Copyright Peter Miller;

All rights reserved.

The program comes with ABSOLUTELY NO WARRANTY; for details use the ' -VERSion License' command. This is free software and you are welcome to redistribute it under certain conditions; for details use the ' -VERSion License' command.

tab(;); l r l. Peter Miller;E-Mail:;millerp@canb.auug.org.au /\/\*;WWW:;http://www.canb.auug.org.au/~millerp/