Yes, I am sometimes amazed at the choices made, the contradiction between omitting data to save storage, while storing the remainder in an inefficient format. An example I dealt with a lot was the "SMF timestamp" format: eight bytes consisting of the time in hundredths of a second past midnight in binary followed by the date in "packed Julian": 00 yy dd dF. No century, even though there are two unused and one constant nibbles; and time in hundredths, even though milliseconds or ten-thousandths would have fit in a 32-bit integer. (And yes, I know they kludged the century for Y2K into one unused nibble.) Not to mention that time in microseconds since 1900 would have fit in a 64-bit integer.
Of course, ease of conversion and formatting is/was also a factor. The year could have been stored in binary, but that might have required conversion from and to decimal as punched into Hollerith cards and printed on reports. Charles -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Seymour J Metz Sent: Wednesday, August 14, 2019 10:21 AM To: [email protected] Subject: Re: Instruction speeds There were other options to reduce the storage requirement of a date, e.g., store them in binary. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
