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. 

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.

Charles


-----Original Message-----
From: IBM Mainframe Assembler List [mailto:[email protected]] On 
Behalf Of Ed Jaffe
Sent: Monday, November 27, 2017 11:59 AM
To: [email protected]
Subject: Re: BDAM files

On 11/27/2017 11:52 AM, John McKown wrote:
>
> ​Well, I don't do much basic I/O, so maybe I'm confused. But doesn't 
> an
> AMODE(31) program require more work than AMODE(24) or maybe I'm 
> thinking RMODE(31)? Or is that just for QSAM program (DCBE and so 
> forth)?​

Back in the day, you had to be in 24-bit mode to call the services, so everyone 
had to write so-called "glue" routines.

The only restriction these days I can think of is that the DCB must reside 
below 16MB (virtual). That's because the DCB pointer in the DEB is only three 
bytes long.

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