Do they really exist? Yes (sort of). In about 1990 we converted a big application program from 24-bit to 31-bit. Basically we just divided our load modules into two halves. One part ran below the 16M line to do all the 24-bit I/O code and the rest was 31-bit AMODE(31), RMODE(ANY). That code is still running fine today on z/OS 2.3. I'm sure we'd have more options today, but that worked in 1990.
On Mon, Nov 27, 2017 at 6:05 PM, Charles Mills <[email protected]> wrote: > It would be awesome if 24-bit would just go away. But are you volunteering > to convert all those 24-bit programs? (Do they really exist? Heck, there's > a > current thread on IBM-MAIN about compatibility with OS/390 1.5.") > > IBM has made the philosophical decision that slavish upward compatibility > is > non-negotiable, except when that principle conflicts with the principle of > integrity. I think IBM over-learned the lesson of the "Future System" > (https://en.wikipedia.org/wiki/IBM_Future_Systems_project#Project_end, > last > paragraph of section) but that is just IMHO. > > Charles > > > -----Original Message----- > From: IBM Mainframe Assembler List [mailto:[email protected] > ] > On Behalf Of Paul Gilmartin > Sent: Monday, November 27, 2017 4:19 PM > To: [email protected] > Subject: Re: BDAM files > > On 2017-11-27, at 14:09:56, Charles Mills wrote: > > > You've got to do a little bit more hoop-jumping for AMODE(31) -- separate > storage for the DCBs, and remembering the extra parameters on the various > macros. Not prohibitive, but a little more to remember, and a few more > possibilities for gotchas. > > > Wouldn't it be great if a single SET symbol setting could condition all the > system macros to generate 24/31/64 bit expansions? > > Better if 24-bit just went away and never came back. And the horse it rode > in on. > > > I have not mentioned this in a while, but I wrote a paper on converting > an > xMODE(24) xSAM program to xMODE(31). If anyone wants a copy, just write me > off-line. Not a sales pitch for anything; no salesman will call. > > -- gil >
