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Re: <TECH> Mercator Help
It's not necessarily from an IBM mainframe, since "zoned overpunch"
characters are still used by COBOL compilers on many systems to represent
signed numeric DISPLAY items.
You are correct that { = +0 and } = -0.
At 04:07 PM 1/28/2003 -0500, wrote:
>John,
>
>I'll give you 10 to 1 that the data is from an IBM mainframe. In EBCDIC
>I believe the correct terminology is "Zoned Decimal" rather than packed
>decimal.
>
>Art Douglas is correct in that it began in the old punched card days. By
>"overpunching" they turned the last character into a representation of
>the numeral plus a sign. That way you can carry the sign within the
>number itself without having to resort to a separate sign (- or +) taking
>up an extra character and having to worry about whether it was a leading
>or trailing sign. When you only had 4K of memory every character
>counted!
>
>If my memory serves me correctly (which happens less frequently as time
>marches on!) the left facing brace "{" represents a positive zero and the
>right facing brace "}" is a negative zero. For example:
>
>10{ = +100
>10} = -100
>10A = +101
>10J = -101
>10I = +109
>10R = -109
>
>
>Allan Bennett
>Cincinnati, OH
--------------------------------
Tom Brandt
Northtech Systems, Inc.
130 S. 1st Street, Suite 220
Ann Arbor, MI 48104-1343
http://www.northtech.com/
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