RE: programming language genealogy

-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx
[mailto:rpg400-l-bounces@xxxxxxxxxxxx]On Behalf Of Jon Paris
Sent: Tuesday, May 27, 2003 3:45 PM
To: rpg400-l@xxxxxxxxxxxx
Subject: programming language genealogy


 >> The direct predecessor of RPG (I) was the plugboard for the 407
accounting machine, which is arguably not a programming language.

>Which is exactly what was meant by tabulators (or tabs) which was the
>generic term used by those who did not live in an IBM centric universe.
>i.e. those of us who programmed Hollerith, British Tab, or ICT equipment.

>They were certainly programmed.  In addition to the wires, the "language"
>one used was often a crude form of Anglo-Saxon <grin>.  Since the RPG
>"language" was very directly aimed at emulating the 407's functions - it is
>after all where we get the RPG cycle and indicators from - I think you have
>to count it as a language and place it directly in the time line.  No other
>language (to my knowledge).  At one time there was some form of conversion
>routine whereby you described the plugboard programming and it generated
>RPG.  Or did you plug the board into a device and it worked it out?
Getting
>too old and suffering from CRS these days so I can't recall the exact
>details.

So RPG was a language on the mainframe before it was used on the mini
systems?  And yet it died out there and became the predominant language on
s/3x.

I think the addition of CALL was the big leap forward for RPG.  The CALL and
PARM opcodes made it very easy to call another program. And the S/38
architecture provided great support for the external program call.

>I'll give you the /free argument <g>

I dont.  RPG's strength is its integration with the OS.  Externally
described files, external program calls, externally described data
structures.  External as in integrate with the OS.  /free was a bit step
forward because it added a lot of procedure call features to the mix while
retaining the OS related stuff.

A way to improve RPG is by integrating it even more to the OS.  Support the
multiple occurance data struct as an object type in os/400.  Then access the
mods in RPG just as it is used now.  Where the OS insures the integrity of
the structure and serializes access.

-Steve