This is an archive of the MAINDEC software diagnostics.

Since the diagnostics files are organized by DEC part number, a word about part numbers is probably in order. A DEC part number might look like any of these: maindec-812-pb maindec-08-d01a-pb maindec-08-d01a-b-pb ac-6527d-ma depending on the vintage of the part in question.

The first of these types of part numbers date from the age of the PDP-5, straight-8, 8/S, and the LINC-8. Not many of those are available here, as yet. The "maindec" identifies the product as a diagnostic, the number specified which product, and the "-pb" or similar suffix indicates the type of media (BIN paper tape).

The second of these types of part numbers date from a little later on. The main innovations are that there is now a "family" code, where "08" means the product works on more than one type of PDP-8, and other family codes indicate a specific type of PDP-8 that the product must be used on. There is also a version encoded as the last letter, so that sometimes later versions of essentially the same diagnostic are available.

The third variation splits out the revision. It also allows an extra character to encode the diagnostic's name, allowing for the much larger number of products available by that time.

The last format is after a grand unification of part numbering across digital product lines. The initial "ac" indicates software media related to a diagnostic. The next four characters after the hyphen identify the individual product, followed by the revision. The last two characters identify the terms of the license, where "m" indicates that no license is required, and the CPU type, where "a" is the PDP-8.

It also became common during this time to use "md" instead of "maindec" when referring to the older part numbers.