Re: 5250 Data Stream + Async I/O

>Thank You all for the comments and 5250 sample code. Now I have another
>question. Actually it is not my question, but one of my friends coming from
>VAX/VMS. He was looking for async I/O on the 400, but found nothing. By
>async I/O we mean that your code sends the I/O request, and gets
>interrupted when the I/O completes. In VMS nearly every I/O operation has
>an asynchronous and a synchronous version. If you choose the async version,
>your program gets interrupted and the I/O handler routine specified by the
>programmer takes control. You don't have to wait for the I/O to complete or
>wait for a notification that you can perform I/O. The closest thing I found
>on the AS/400 was the SIGIO signal for sockets (which is POSIX, not AS/400
>specific). BTW POSIX provides async I/O, but it's not widespread yet -
>OS/400 does not support POSIX aio_ functions either. Does OS/400 provide
>async I/O for application developers (system programmers)?
>Regards,
>     Benjamin Budai


Benjamin;

A).  Forget that paradigm.  He doesn't have to do the work of the OS
anymore.
        It is smart enough to do the right thing.  Trust it.

B).  What language are you thinking about using?

If the language is  RPG, COBOL,  or something using embedded SQL,       
the machine will control the I/O and whether it's Async or just Sync.

If you are doing "Sequential"  file processing, (ie Reading records without
using a 
key - in RPG/COBOL jargon),  You can do an OVRDBF and use the  NBRRCDS 
parameter to let the system do blocking.   Look up and read on Sequential
File
Processing.   It will tell you about the AS/400's  use of Sync and ASync
file
processing.  These things also come into play if you use a command like
OPNQRYF.
Read about that command and see what you find out.

John Carr


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