IBM BOOK format

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IBM BookManager is IBM's legacy online documentation system, historically used mostly on mainframes, midrange (AS/400) and OS/2, although it also saw some use in other areas including AIX. IBM no longer uses it for documenting current versions of its products, but there is an immense quantity of surviving electronic documentation from the period when IBM actively used it (from the 1990s thru 2010s), particularly documentation CD-ROMs/DVD-ROMs and images thereof.

The standard extension is BOO. The header of BOO files commonly contains an EBCDIC copyright notice (this is true even for books for ASCII-based platforms such as OS/2). The file contents is almost certainly also in EBCDIC, but is not readable beyond the header. Most likely this due to compression with an unknown algorithms (a relative of IBM's well-known proprietary algorithms such as TERSE?). However, the data seems too repetitive to be compressed–possibly it is just some obfuscation mechanism then?

"application/book" is sometimes used as a MIME type but was never officially registered.

Notes on file format

• Bytes 1-2: unknown 2 bytes probably flags. second byte never zero, first byte often is (but not always). probably not a size, since 0001 is a common value.
• Bytes 3-6: these 4 bytes appear to always be zero
• Bytes 7: unknown, can be zero, probably more flags???

Bytes 8+: EBCDIC copyright string. Can start with one or more EBCDIC spaces (0x40), sometimes also (0xB4) (some kind of control character?)

The header is 256 bytes long. The copyright string is padded to the end of the header with 0x40 (EBCDIC space). However, it seems to have a null terminator (0x00) at the end of the actual text, before the space padding.

What follows from 256 bytes onwards looks like it could be some kind of compression dictionary. Not clear.

It looks like the file is composed of 256 byte records (so file size should be an integer multiple of 256), often with some all-zeros records appended to the end.

There is weak evidence that the file format might be record oriented with 4096 byte records: IBM upload instructions into MVS datasets hint towards that. All known files so far have a file size which can be divided by 4096 without remainder. If the file size doesn't match, it's padded with binary zeros.

See also

• Reviving InfoSeeker

Weblinks

• BookManager Releases contains history of IBM BookManager releases
• Using PDFs and BookManager Books on your workstation or mainframe, IBM.com
• Terse (file format), Wikipedia
• LZ77 and LZ78 compression algorithms, Wikipedia
• Data compression method for TERSE, patents.google.com
• ZIP archive file format, archiveteam.org, mentions TERSE.
• terse for PCs (Windows, AIX, Linux ....), hercules-390@yahoogroups.com
• TRSMAIN question, IBM-Main mailing list