FORTRAN used numeric statement labels on the left as reference points,
but these were not "sequence" numbers, as there was no semantic
requirement to have statements ordered by numeric label or to have any
predictable increment among statement numbers. Typical coding
standards, where they existed, usually mandated some semblance of order
is use of statement labels, but that was for benefit of human readers,
not the compiler. I'm not sure about the latest flavors of free-format
FORTRAN, but at least through FORTRAN IV, columns 73-80 of each input
record were reserved for sequence numbers
J C Ewing
On 04/07/2013 04:55 PM, Charles Mills wrote:
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:IBM-MAIN@LISTSERV.UA.EDU] On Behalf
Of Paul Gilmartin
Sent: Sunday, April 07, 2013 2:40 PM
To: IBM-MAIN@LISTSERV.UA.EDU
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.
--
Joel C. Ewing, Bentonville, AR jcew...@acm.org
----------------------------------------------------------------------
For IBM-MAIN subscribe / signoff / archive access instructions,
send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
