RE: allow multiple threads in interactive job

> -----Original Message-----
> From: midrange-l-bounces@xxxxxxxxxxxx
> [mailto:midrange-l-bounces@xxxxxxxxxxxx]On Behalf Of Steve Richter
> Sent: Friday, February 11, 2005 12:15 PM
> To: Midrange Systems Technical Discussion
> Subject: Re: allow multiple threads in interactive job
> 
> 
> 
> 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


My understanding is that threads were originally developed on other systems to 
work around those systems limitations of process switching and sharing between 
processes.  The AS/400 never had such limitations so multi-threading wasn't a 
requirement originally.

http://www.serpentine.com/~bos/os-faq/FAQ-1.html#Threads
http://www.serpentine.com/~bos/os-faq/FAQ-1.html#The-history-of-threads

As I understand it, the only reason threads were added to the 400 was to 
support Client-Server type applications where you are constantly starting and 
ending threads.  Since a process startup on the 400 is still "exspensive".

End result, thread support on the 400 is a recent requirement, and no doubt 
will improve as time goes on.

HTH,
Charles