MacIvory FEP diagnostics

A quick note to try to make this information available on the net.

Trying to troubleshoot my Symbolics MacIvory, where my Quadra 900 was encountering bus errors from time-to-time and, at least once, Genera spammed me with tens of thousands of notifications about low-level drawing operations gone bad, I wanted to exercise the NuBus memory card (a National Semiconductor NS 8/16 with only 8 MB of RAM).

The FEP ("Front End Processor") contains a memory test routine, but it has to be explicitly loaded.

FEP Command: 

 is the prompt that shows you are talking to the "MacIvory FEP"; in the "Ivory" menu of the Genera application, you should be able to "Transfer to the FEP".

 The FEP prompt responds to the "help" key, by the way, and has commands like "Show Command Tree" that shows the loaded commands.

 FEP commands themselves are stored in .FLOD files.

 Show Directory FEP0:>*.FLOD.newest

will list them. "I328-" in the name indicates they are for the MacIvory Genera 8.3 release. The trick is that I328-TESTS.FLOD.newest is not loaded by default, so the commands are not available. The Scan File command will add the functions of a FLOD file to the available commands.

 Scan File I328-Tests.FLOD.newest

includes a Test Main Memory diagnostic; Test <help> will show what is available, in my case

Test All
Test Location
Test Main Memory
Test Simple Main Memory

Test Main Memory then tests "00003766763 Main memory locations (00001011015->00005000000)" and takes about a minute (printing out dots while it progresses).

For better or worse, it did not report any errors for me, so I hope that rules out the memory board for now.

If you want to know more about how the FEP boots the machine, the Site Operations Manual documents the contents of the various .BOOT files and how they are executed to initialize the Ivory (including network addresses) and load and then start the Lisp world.

 Boot FEP0:>Boot.boot.newest

 is the most likely command to start the Lisp machine.

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