MM/PC Applications: Y2K and Tape Header Dates

Labelled tapes contain two dates in the header, creation date and expiry date. The format of the date is YYJJJ, where YY is the last 2 digits of the year, e.g. 99, for 1999, and JJJ is the julian day of the year. Thus 5 will 5th  January, and 350, mid December.

In about 1985 the date format was changed slightly to make it year 2000 compliant. The date, e.g. 99310 is always preceded by a space, this space now has the meaning of 19. For the year 2000, the space is replaced by a '0', and 2100, by a '1'. Thus  99001 is Jan 1 1999, and 000001 is Jan 1 2000. Jan 1 2400 will be 400001. Come the third millennium there may be problem, but we could always start 'A', 'B' etc, and not many of us will be about by then .

At InterMedia we see many tapes from many sources and expiry dates are now often in the year 2000. However, many headers are incorrect, and giving an expiry date of 1900, i.e. they still have a space rather than a '0' Will this cause problems? Possibly if the reading system actually notes these dates. Also, tapes in 2000 will be generated with the incorrect creation date. Any automatic file cleansing system could have a field day on Jan 1 2000.

Action, check that the dates on your tape headers are correct, and industry compatible.

MMPC has a scan function that will decode headers and allow you to examine the dates. It will also read tapes in any format, so if the host system will not restore the tape, MMPC will, and you could rewrite the tape with valid headers.

A free fully functional 30 day demo package can be downloaded from www.intermedia.uk.com/MMPC/download.htm

 

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eMag Solutions
(formerly InterMedia)

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Mulberry Drive
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Cardiff
CF23 8RS
United Kingdom

Tel (44) 02920 739940
Fax (44) 02920 739948