On Tue, 3 May 2011 09:03:12 -0500, John McKown wrote: >Then explain them to this poor fool. I find them to be a useless >anachronism. And your answers tend to be so short as to be unhelpful. > PACK, surely. Nowadays, that function is best left to microcode in the DASD subsystem so it can be transparent to all applications. (Unless you consider CPU cycles cheaper than I/O bandwidth.)
>On May 3, 2011 8:03 AM, "Shmuel Metz (Seymour J.)" wrote: > >>And, yes, I know about ISPF's "modification level" use of the >>sequence columns. >Suggesting that you don't understand the issues. The use of columns >79-90 is only a minor part of why sequence numbers are useful. > I've long wondered, if sequence numbers are so valuable, why haven't they spread outside the progeny of unit record systems? o Well, there's COBOL, which allows sequence numbers at both left and right ends of the line. o And BASIC, or at least used to be. Does Microsoft VBA still use sequence numbers for editing? And have a RENUMBER command wihch updates GOTOs accordingly? o A colleague once described to me an [S|X]DS Sigma system which stored text files as a sort of KSDS (no, not the San Diego radio station). The keys were the sequence numbers, and mandatory. I suppose this allowed efficient insertion or deletion of lines. o PDP-6 et seq. stored 5 USASCII characters in a 36-bit word. If the sign bit was set in the first word in a line, that word was treated as a sequence number (but by what translators or applications?) Most of these conventions are obsolescent. -- gil ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
