Code Magus Binary Access Method

The Binary Access Method is used to read and write records of binary data, either as fixed length or variable length records.

Product Description

The Binary Access Method is used to read and write records of binary data. The access method delimits records either as fixed or variable length. For a fixed length record the length is supplied by the caller and the file size must be a multiple of the record length. For variable length records the length is prepended to the data record in the style of a z/OS MVS Record Descriptor Word (RDW). The RDW is 4 bytes long and only the first two bytes specify the length as big endian value.

http://www.codemagus.com/documents/binaryam_CML0000601.pdf