"No more processes."

Every OS has limits set somewhere. Stacks can only get so big, etc. A lot of the art of systems programming lies in setting those limits so that they neither get in the way of normal use nor allow the system to be overwhelmed or destabilized, or to become inefficient because some of the system's code or hardware only scales up so well.

I don't think too many people are going to complain about a consumer OS that can "only" run 116 applications at once on consumer (i.e., personal computer) hardware. I can't imagine that Mac OS 9 would get anywhere close to that before it gave out less gracefully than OS X did.
Apple can probably adjust the max number of processes or threads allowed, per system or per user, without too much trouble. But why?

[ 12-06-2001: Message edited by: Amorph ]</p>

There's no pleasing some people.

The process table size is probbally hardcoded in the sourcecode. Some versions of Unix allow you to modify these variables on the fly. I don't know if OSX supports that.

Why the hell do you have that many apps open anyway?

Scott H. wrote:

[quote]AFAIK all Unix systems have a limit. I think I've hit it a time or two. But only when all hell breaks loose.<hr></blockquote>

Sure. These appeared not long after it was discovered that a fork() bomb - whether deliberate or accidental - could bring a UNIX machine down within seconds if it was left unchecked.

Far better to have an artificial limit that allows the OS to recover gracefully and continue than to let user-space applications bring the whole system down.

In this case, that limit is almost certainly not going to be reached under normal circumstances.

The funny thing is, if John Siracusa had published something like this, there would probably be at least one thread crowing about how awesome OS X because it can run so many apps at once without getting fazed.

[ 12-06-2001: Message edited by: Amorph ]</p>

[quote]Originally posted by starfleetX:
<strong>Does Mac OS X have a limit on the number of threads it can run?? :confused:

.
.
.

Does anyone else have some info about this? <img src="graemlins/hmmm.gif" border="0" alt="[Hmmm]" /> </strong><hr></blockquote>

starfleetX:

As others have posted -- there are limits. For your enjoyment you can list many of these via the terminal.app command 'sysctl'. I give you a partial list of mine below.

Notice the 'kern.maxproc = 532' in answer to your inquiry. This means my system will support no more than 532 *simultaneous* processes. This number is likely to be slight;y lower as the OS will require a few to unravel the situation as you approach this max of 532.

You can modify some of these limits if you wish. See the sysctl man pages. I've extracted some of the examples from the sysctl man page for your enjoyment below.

EXAMPLES
For example, to retrieve the maximum number of processes allowed in the
system, one would use the follow request:
sysctl kern.maxproc

To set the maximum number of processes allowed in the system to 1000, one
would use the follow request:
sysctl -w kern.maxproc=1000

Information about the system clock rate may be obtained with:
sysctl kern.clockrate

Information about the load average history may be obtained with
sysctl vm.loadavg

Regards... Barry Sharp

Output from the sysctl command...

iMacDV% sysctl -a
kern.ostype = Darwin
kern.osrelease = 5.1
kern.osrevision = 199506
kern.version = Darwin Kernel Version 5.1:
Tue Oct 30 00:06:34 PST 2001; root:xnu/xnu-201.5.obj~1/RELEASE_PPC
kern.maxvnodes = 17200
kern.maxproc = 532
kern.maxfiles = 12288
kern.argmax = 65536
kern.securelevel = 1
kern.hostname = iMacDV
kern.hostid = 419377504
kern.clockrate: hz = 100, tick = 10000, profhz = 100, stathz = 100
kern.posix1version = 198808
kern.ngroups = 16
kern.job_control = 1
kern.saved_ids = 0
kern.boottime = Sun Dec 2 11:59:58 2001

[ 12-06-2001: Message edited by: Barry Sharp ]</p>

Didn't you already post this?

<a href="http://forums.macnn.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=46&t=001582" target="_blank">http://forums.macnn.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=46&t=001582</a>

Anyway, I was always curious as to how small dock items could get ... it seems to go on forever

I did this on 10.0.4 and the system was just as speedy as ever. Launching new apps was slower than normal, but currently running apps chugged away without a burp.

<a href="http://www.hekal.org/pictures/wow.jpg" target="_blank">Click to see.</a>

[quote]Originally posted by starfleetX:
<strong>I tried going through some (okay, A LOT) of Carbon and Cocoa (no Classic) apps to stress-test my Mac. Well, after a while I tried running 'top' in the terminal, I got the message "No more processes." WTF??

Does Mac OS X have a limit on the number of threads it can run?? :confused:

So much for the world's most advanced Operating System...

Here are <a href="http://brad.project-think.com/movies/myRunningApps.mov" target="_blank">the apps I was running</a>.
Here's a shot of Terminal.app saying I <a href="http://brad.project-think.com/images/NoMoreProcesses.jpg" target="_blank">can't run "top" or "hostinfo"</a>.
Even the Process Viewer <a href="http://brad.project-think.com/images/ProcessViewerStuck.jpg" target="_blank">wouldn't work properly</a> because it relies on top.

Does anyone else have some info about this? <img src="graemlins/hmmm.gif" border="0" alt="[Hmmm]" /> </strong><hr></blockquote>