Re: ancient PL/I, was fledgling assembler programmer

gah4 <gah4@u.washington.edu>
Sat, 25 Mar 2023 01:27:18 -0700 (PDT)

          From comp.compilers
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[2 earlier articles]
Re: fledgling assembler programmer tkoenig@netcologne.de (Thomas Koenig) (2023-03-22)
Re: fledgling assembler programmer gah4@u.washington.edu (gah4) (2023-03-22)
Re: fledgling assembler programmer tkoenig@netcologne.de (Thomas Koenig) (2023-03-23)
Re: fledgling assembler programmer gah4@u.washington.edu (gah4) (2023-03-24)
Re: ancient PL/I, was fledgling assembler programmer drb@ihatespam.msu.edu (2023-03-24)
Re: ancient PL/I, was fledgling assembler programmer gah4@u.washington.edu (gah4) (2023-03-24)
Re: ancient PL/I, was fledgling assembler programmer gah4@u.washington.edu (gah4) (2023-03-25)
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From: gah4 <gah4@u.washington.edu>
Newsgroups: comp.compilers
Date: Sat, 25 Mar 2023 01:27:18 -0700 (PDT)
Organization: Compilers Central
References: 23-03-001 23-03-002 23-03-003 23-03-007 23-03-008 23-03-012 23-03-013 23-03-014
Injection-Info: gal.iecc.com; posting-host="news.iecc.com:2001:470:1f07:1126:0:676f:7373:6970"; logging-data="25777"; mail-complaints-to="abuse@iecc.com"
Keywords: PL/I, history
Posted-Date: 25 Mar 2023 10:47:03 EDT
In-Reply-To: 23-03-014

On Saturday, March 25, 2023 at 12:09:30 AM UTC-7, gah4 wrote:


(snip)


> It is what IBM calls, I believe, dynamic overlay. Each module specifically
> requests others to be loaded into memory. If there is enough memory,
> they can stay, otherwise they are removed.


Traditional overlays are generated by the linkage editor, and have
static offsets determined at link time.


PL/I (F) uses OS/360 LINK, LOAD, and DELETE macros to dynamically
load and unload modules. The addresses are not static. IBM says:


        "The compiler consists of a number of phases
          under the supervision of compiler control
          routines. The compiler communicates with
          the control program of the operating
          system, for input/output and other
          services, through the control routines."


All described in:


http://bitsavers.trailing-edge.com/pdf/ibm/360/pli/GY28-6800-5_PL1_F_Program_Logic_Manual_197112.pdf


They do seem to be called phases, but there are both physical and
logical phases, where physical phases are what are more commonly
called phases. There are way more than 100 modules, but I stopped
counting.


(snip)
> [Never heard of dynamic overlays on S/360. -John]


It seems not to actually have a name.

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