johnm at wdi.disney.com wrote:
> michal starke <Michal.Starke at lettres.unige.ch> wrote:
> > > Playing around for a bit with the morph interface, is also almost
> > > guaranteed to get the VM in a closed loop.
> > 
> > Is morphic running correctly on anyone's (intel) linux box [modulo sound]
> > or is this a generalised problem?
> > (I am considering a switch to linux but need to work on morhpic a lot...)
> 

I don't know how I didn't notice this thread!

Here are a couple of landmines for Linux users (maybe this should be on the Swiki somewhere?):

	1) Make sure you have a VM that is up to date; there was a time over last summer where new images actually wouldn't work with old VM's.  Probably any VM made since September will be fine.

	2) If you compiled your own sources, check that sq.h does NOT #define ioLowResMSecs.  The default definition is based on clock(), which won't work on Linux.  clock() only advances when the process is consuming CPU; thus, using a clock()-based definition on Unix can cause Squeak to hang in times of low CPU usage.  If you notice Squeak hanging with 0 CPU usage, this might be the reason.  Delete the #define and recompile.

	3) Set up sound.  If you haven't specifically compiled in sound support, then setting the disableSounds preference is the safest thing.  There are combinations of the Unix VM and Squeak image which will hang the image at 100% CPU once sound starts playing.  (Though I'd think alt-period would still work in this case).  Note that certain morphic operations, in particular bookmorph page turns, cause sounds to be played.

These aside, I have seen a *few* lockups at 100% CPU that I couldn't explain.  They all happened over the last couple of weeks, when I was at home over a PPP link instead of over ethernet.  "strace" reported that Squeak was doing lots of gettimeofday()'s, for whatever that helps.  It always happened after I downloaded my email using Squeak's mail reader.  Squeak would lock hard, at 100% CPU, and even alt-period had no visible effect.

But as John mentioned, I worked over a PPP link all of last summer and didn't see any of these unexplainable lockups....  And I'm not seeing them now that I'm back at Tech.  It may well have been some change I had added to that image which wasn't so bright after all--I seem to do that a lot!  It's hard to say, which is why I hadn't mentioned it before.  But I mention it now to be fair.


I guess the main point here is that Squeak is certainly being used on Linux.  It's not some old dusty proof of concept that has been forgotten.  If you're seeing problems, there are people who would like a stab at fixing them.


Lex