Re: allow multiple threads in interactive job

On Fri, 11 Feb 2005 12:38:04 -0600, Patrick Botz <botz@xxxxxxxxxx> wrote:
> The reason interactive jobs were not enabled to support multi-threaded
> applications is that large pieces of the internal OS which they use are not
> capable of handling multiple threads.  The cost to multi-thread enable the
> whole system was huge.  Therefore the decision was made (way back when this
> was orginally done) to support multiple threads in those environments that
> did not require an entire rewrite of major portions of the internals of the
> OS.

which is a great argument for open sourcing the as400.  IBM management
might not be willing to invest in the system, but the open source
community certainly would.

-Steve

> 
> Patrick Botz
> 
> 
>             Steve Richter
>             <stephenrichter@g
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> 
>             02/11/2005 11:15                                      Subject
>             AM                        Re: allow multiple threads in
>                                       interactive job
> 
>             Please respond to
>             Midrange Systems
>                 Technical
>                Discussion
> 
> On Fri, 11 Feb 2005 10:40:13 -0600, Bruce Vining <bvining@xxxxxxxxxx>
> wrote:
> >
> >
> > >From the V5R3 Information Center:
> 
> thanks Bruce.
> 
> > ...Interactive and communication jobs do no provide multithread-capable
> > support.
> 
> that stinks!  I was going to try and implement a message loop style of
> programming in an interactive job.  The idea being to use the C record
> io functions for display file i/o in a 2nd thread of the job.  A 3rd
> thread might wait on an object lock.  or do a dlyjob. I was thinking
> you could even use RCVJRNE to place a message on the message loop
> queue when a record was added to a file.  All the threads then feed
> their input to the data queue that the interactive job receives from
> as its message loop.
> 
> Was not sure if I could cancel a display file read in the background
> thread without using INVITE or not.
> 
> Too bad IBM places all these restrictions on their system.
> 
> thanks,
> 
> -Steve
> --