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Posted By

siz
on 2007-05-04
05:02:52
 Re: Indirect,X

BCD mode is used on midrange and mainframe computers for fixed point numeric calculations where higher accuracy is required than the floating point arithmetic can support. (for example 0.3 can not be represented in floating point because it gives an infinite binary fraction part.
According to Bionic it could be represented as 1 byte/digit but in the old times the storage was expensive and the engineers must did something about that.
I work on a telephone usage billing system that runs on the midrange IBM i5 system (formerly AS/400) and it's main number format is a descendant of BCD (called packed decimal where the last BCD digit is the sign). When we store 10 millions of calls and all of their data it DOES matter if we use BCD or one byte per digit. (Floating point is not acceptable as mentioned above)



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