real time process calls in SunOS

[Joseph Warden]

The following query was received in response to my posting:

|I am very interested in your responses, as we are doing basically the same
|thing. The difference being our original acquisition was done by hardware,
|and now it is on the Sun.  We are using a real-time processor in a VME
|chassis to get the data and then we send it to the Sun over a parallel
|line.  Our problem is displaying it fast enough on the Sun.
|
|For another effort I am interested in, the OS you are running on the
|PDP-11.  We run Ultrix-11 on ours and it is incredibly slow.  Sounds like
|what you have might help us out.  Does it support IPC messages and shared
|memory?

Here are the only responses I received:

----- Begin Included Messages -----

I don't know about 4.0, but 3.5 does not have a call named rtp, nor have I
been able to locate anything applicable with man -k (which searches for
keywords in man-page subject lines).

Since you're an educational installation, I presume that you have the 2.9
BSD source, and may also be able to get SunOS source fairly inexpensively.
If I'm right about that, it might not be too hideous to port the rtp()
service to SunOS.

Based on what I've heard, 4.0 uses considerably more memory than 3.5 and
thus is not a real good idea on a 3/50, unless you add one of the
third-party memory expansion hacks.  (Sun does not support memory
expansion of the 3/50.)

**** End of Message ****

X_Subject: Re: Real time process calls in SunOS

>Implementation of the data collection routines was facilitated by the
>rtp() call available in the 2.9 distribution. This call originated in AT&T
>Unix V7 and permits the current process to be locked into memory and
>suspends polling.

V7 did, as I remember, have a "lock()" call that locked processes into
memory.  (What does "suspend polling" mean?  "lock()" didn't suspend task
switching, if that's what you mean.)  However, BSD didn't have it.

>Does SunOS 4.0.x contain an equivalent call?

No.  SunOS 4.1 will have calls to lock pages into memory, but not to
suspend task switching.  S5R4 will, I think, have both, and Sun's
S5R4-based future release will thus have them.

**** End of Message ****

X_From: dan at rose3.rosemount.com (Dan Messinger)
X_Subject:Re: Real time process calls in SunOS

I suggest you talk to Sun.   I know they have a solution.  But I've signed
non-disclosure agreements on anything they tell me that they haven't
announced.  I dare not say more.

dan at ernie.rosemount.com

----- End Included Messages -----

Thanks to those who responded.

If you wish I could send you a preprint of our approach which is to be
published in the Journal of Chemical Information and Computer Science.

Joseph Warden