EBCDIC

EBCDIC had all sorts of representations. The most variation was in the area of control characters (0x00 to 0x3F). Most of the alpha symbols were pretty standard. The best help was if you knew how cards were punched. That helped quite a bit, but there were all sorts of wierdnesses. The most blantant one was the translation of 0-2-8 (it is labeled that way on an 029 keypunch) into 0xE0. It didn't match the "pattern" at all. I helped design (with logic gates) a converter from card code to EBCDIC and it wasn't fun. It was before roms were wide spread which would make the job MUCH easier. Proper card codes had only a single punch in rows 1-7 (or none) which can be coded as three bits. The other rows (12, 11, 0, 8, 9) made up the other 5 bits. Shuffle that thru a 1702 ROM (256 addresses, 8 bits) and you could (with proper programming) get EBCDIC out the other end. The proper programming of the ROM is left as an excercise to the reader. Another observation: A long time ago I wandered into the DMV to do some menial task, and they had a big thick book of "taken" vanity plates. Having some time to waste, I looked thru it and saw the plate "E2C5E7" listed, and also the plate "E2C5E7Y" listed. Their interpretation is also left as an excercise to the reader. So EBCDIC lives on in wierd ways, where numbers need to be collated AFTER letters. -- Tom Watson tsw at johana.com __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com