Y means Yes. N means NO. ? means dunno. n/a means who cares.
For Decision Table Nerds: The combination logic for Acceptable and Borderline is AND, Unacceptables are OR.
This is the Y2k Cinderella Availability index. Availability Index
The display varies from the ISO/ANSI/FIPS norm. Seeing we have got by without worrying about this in the past, let us now cut ourselves some slack. Display means machine to Human interface. Humans can infer context and can understand the message.
This is to do with the internal binary storage format of the operating system. This is an absolutely essential ingredient for Acceptability. If there is an N in this column, throw the wretched thing away.
Humans are able to read almost any old date format that you throw at them. However the older d/m/y and m/d/y forms are and always have been ambiguous and we are trying to get away from these older form 2 digit years. Humans can even understand garbled output (within reason).
Even though the internal binary forms are correct, the two digit year forms do not enable humans to easily distinguish between 1996 and 2096 (and over). As I am unlikely to last another 100 years, particularly under the strain of replying to anti-Cinderella bigots, I personally am prepared to leave this as an exercise for future generations. We'll probably all have Net implants by then anyway.
In some rare cases the display is so garbled that even humans cannot make sense of it. The decision between Acceptable and Unacceptable is then based on whether the date display is germane or not. If program execution causes correct binary output irrespective of display, then the program is Acceptable. The deciding factor is always the binary input and output. If files are wrong or Interface becomes N, the program is Unacceptable.
This is a difficult one to define and test. It is to do with Interfacing to other systems. In our context we will assume that this means linking via Comms, Net, Mail, Lan etc. It is crucial. Like binary format, if there is an N, Triage applies. In terms of FIPS this is probably the only MUST requirement.
Another difficult to define but crucial category. Calculations on dates are many and various and usually depend on the contents of files and assumptions about layout. Application programs will croak if unable to calculate. Hard to spot, but an N means Triage.
Comparing of dates is like Calc, normally performed internally by application programs. However the newer formats can be sorted and compared directly when stored as character (text) data.
Sort refers to the ability to sort character (text) data directly. The Y/M/D forms are usually directly sortable. Leading zeros tend to be important when sorting text data. Nice to have. Elegant but not essential. An N is not terminal.