WarpSE: 25 MHz 68HC000-based accelerator for Mac SE
- Thread starter Zane Kaminski
- Start date
I tested it today but found HeapTool 1.4 doesn't resolve the low memory issue that triggers the error message in SCSI Director Pro 4.0.
The author of HeapTool made it for System 6 and says it "probably" wouldn't have any meaning under System 7 due to the way 7 handles the heap in a much better way. But he left the door open for the possibility it might help. Even so, after getting the memory error in SCSI Director Pro, I quite the app and opened the HeapTool control panel and clicked the PURGE button. All that does is create a little more white space at the far right of the bar for System Software. The total RAM allocation doesn't change. So in the case of your screenshot above, the 1,602K would not change, and the Largest Unused Block number would not change after clicking the PURGE button. It only clears out some RAM that is already allocated for System Software, which SCSI Director Pro cannot touch. That's why after clicking PURGE and then relaunching SCSI Director Pro 4.0, the same memory error occurs.
I am guessing it's a coding quirk of SCSI Director Pro 4.0. Even though I have given it 1024K in the Get Info Box, if it sees the Largest Unused Block (of RAM) to be less than about 1500K, then it complains it is out of memory (after the initial tests complete, just before the graphing tests begin). So long as I can keep the Largest Unused Block higher than about 1500K, then SCSI Director Pro 4.0 is content to perform all the tests, including the graphing tests.
Anyone can simulate this problem easily, without fiddling with INITs by trial and error. Just increase the Disk Cache in the Memory control panel to be 384K instead of the default 128K. That usually will drop your Largest Unused Block of RAM to below 1500K, thereby triggering the out of memory issue in SCSI Director Pro 4.0 (just before the graphing tests begin).
And for whatever reason, no, adjusting the Minimum and Preferred settings in the Get Info box for SCSI Director Pro 4.0 doesn't solve the problem. I think it's a bug in the app, ignoring those settings. The only way to prevent the error is like I said. You have to increase the Largest Unused Block of RAM to above 1500K or so.