johnd@phred.UUCP (07/19/90)
My apologies if this has been mentioned before... My department has just installed system 6.0.5 on our four IIcis and one Plus. Everything has been fine except that the Plus, which has been running Empower (a security program) with system 6.0.4 for over a month with no problem, suddenly brings up a message that says, "The 'System' file on this startup disk may be damaged. The installer can be used to repair this disk". We called Magna, the publisher of Empower, and they said, in essence, that it wasn't their fault--Apple set the default system heap size to 128K, and if you change that size to 192K or 256K, it will work. First of all, I haven't the slightest idea what the system heap is for--my suspicion is that it has something to do with the system's RAM allocation. I also suspect that Magna may not have followed Apple's guidelines when they developed Empower and got "caught" with the system upgrade. All my other programs seem to be compatible with the new system. How do I change the system heap size? Is this a good idea? Anyone else had similar problems? Who really messed up--Magna or Apple? I'm reluctant to mess with a perfectly good system just for one application when MacPassword seems not to have a problem with the upgrade. Thanks for your help
drew@cup.portal.com (Andrew E Wade) (07/19/90)
Re: System heap size too small, causing problems. This is not the application's fault. As you use more INITs, CDEVs, etc., you can run out of system heap space. You should set it up using CE Software's Heapfixer (Des Moines, Ia, or you local dealer -- heapfixer is bundled with several of their products). Remember to set it again whenever you install new system software. There are no dangers or bad side effects of this -- except that it uses some of your memory! (You can also set it with resedit, but heapfixer is safer.) Insufficient system heap size is one of the most common causes of occasional unexplained crashes. In the finder, do the About...command and look at the system memory bar. It should have about 25% or more of free (white) space. If it doesn't, you may occasionally run out of memory in system utilities and inits, etc. If you use multi-finder you may also want to set up finder's size. Select finder icon, command-i (get info), edit number in lower right-hand corner up from default 160KB to something like 256KB. I'm not aware of this causing crashes, but i've certainly seen the finder complain about insufficient memory, e.g., when trying to copy large numbers of files. Again, no bad effects except that it uses memory. Memory is worth it. If you're short buy some. It's cheap. Good luck. Hope this does it for you. -Drew Wade Objectivity, Inc. 800 El Camino Real, 4th Floor Menlo Park, CA 94025 (415) 688-8000 fax: (415) 325-0939 email: drew@objy.com