Culture is a key here. IBM's background was in punched cards. IBM's strength in punched card tabulating is what transferred over to their success in computer data processing. They never forgot that.
Many other computer systems' analog of the punched card was punched paper tape. We see that legacy today. z/OS's model of a file is one of discrete records with "hard" boundaries. UNIX's model of a file is a continuous undifferentiated stream of characters. BASIC and FORTRAN both used sequence numbers as "labels" but they were on the left, not the right, correct? Speaking of not portable program formats, didn't Symbolic Optimal Assembly Program (SOAP) optimize code speed by scattering instructions around a drum such that the next instruction to be executed was just coming under the read head? Charles -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Paul Gilmartin Sent: Sunday, April 07, 2013 2:40 PM To: [email protected] Subject: Re: 32760? (was: PARMDD?) On Sun, 7 Apr 2013 11:35:37 -0700, Charles Mills wrote: > >> I dislike sequence numbers anyway > >A completely different topic, but sequence numbers are obviously (I think. Am >I wrong?) entirely a vestigial organ left from the days of punched cards. They >were a lifesaver if you dropped your cards on the floor, and the compilers put >out a warning if you loaded the cards into the reader in incorrect order. > I understand that the 709 (sometimes) read cards in row binary format, two 36-bit words to a row, so 8 columns were inaccessible. (You could select which 8 with a wiring board). This pretty much solidified the number 8. But do sequence numbers have a lick of value today? > Shmuel and some of my coworkers think so. A telling observation is that few editors other than from the IBM culture implement them. BASIC used them both for editing and GOTO targets. Long ago, a colleague described to me a SDS/Xerox Sigma system that kept program source in something akin to a KSDS. The line numbers were the keys, and absolutely essential. Hardly portable. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
