What's this 19100 glitch?

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I'm an Associated Press reporter and I'm looking for a programmer to explain to me this glitch that has come up on a number of Web sites, showing years as "19100" rather than "2000"

Thanks, Frank Bajak Associated Press fiftyrock@mindspring.com

-- Frank Bajak (fiftyrock@mindspring.com), December 31, 1999


There is a "C" language function which returns the year as a number beyond 1900. So in 1987, it returns "87". In 2000, it returns "100".

When a programmer wants to display the date, he/she should say 1900+YEAR (1900+100=2000, which would be correct).

But stupidly, they hard code 19, and then add "YEAR". The result: 19100.

-- David Holladay (davidh@brailleplanet.org), December 31, 1999.


I don't think you need a computer programmer for that one. A century two digit field had maximum value of 19 or a fixed value of 19, and a year field which allowed more than two characters went from 99 to 100!

(P.S. All we ask from you is the truth, the whole truth, and nothing but the truth. Happy New Year!)

-- cgbg jr (cgbgjr@webtv.net), December 31, 1999.


"Another insidious problem is one often referred to as a "Register overflow" although it is not restricted to date data reads in registers alone but in all the data read and storage facilities available to the program after the overflow. This results when an incremental year counter moving from 99 goes to 100, not 00, and results in an extra character in a 2 digit space, which if not discarded "corrupts" all the other stored and manipulated data by 1 character.

Y2k YEAR Dates we've seen: 19100 1900 1980 1986 1994 00 100 ?? :0 2000 (and there are others)

And one more issue: even printers can become problematic if not updated. Dates can be an issue on servers configured with TCP/IP, at which point the SNMP services might be enabled, and SNMP ia a date oriented protocol. HP has noted that their 'Jet Direct' cards for printers are "compliant with customer installation" on TCP/IP Networks, meaning the customer has to install the upgrade to make it work correctly. See http://www.hp.com/cposupport/networking/support_doc/bpj05431.html for more details. "

This url gave me an 11 page printout, with the clip here in the middle of page 9.

-- Hokie (Hokie_@hotmail.com), December 31, 1999.

Oh, credit for that snip goes to Mark SLotnick, posted earlier this morning. His e-mail is on the post, if you wanted to ask him to clarify the text.

-- Hokie (Hokie_@hotmail.com), December 31, 1999.

Holladay is correct. Jocelyn Amon has written about this, calling it "booby trap" code: No code is immune.

-- Lane Core Jr. (elcore@sgi.net), December 31, 1999.

Maybe it's a real common glitch

-- spider (spider0@usa.net), January 1, 19100

-- spider (spider0@usa.net), December 31, 1999.

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