🚀 go-pugleaf

I've run into an unusual problem with Macsbug, and I hope someone out there
in netland can shed some light on it.

In a "normal" Mac (thin or fat), Macsbug, Maxbug, and their relatives live
at or near the top of physical memory, away from the heap, stack, screen,
and other interesting data structures.  Because Apple warns that Macsbug
and company *do not* work in a Lisa (use Lisabug instead), I imagined that
Macsbug's use of memory reflected the expected limits of a Mac (i.e., never
more than 512K).

The problem:  when I use Maxbug in my obese Mac (1.5 megabytes), the code
seems to be located just under the 512K boundary (as is normal), but
something related to Maxbug goes in the extended memory area.
The symptom: when my 1-meg ramdisk is about half-full, the Mac falls into a
very confused Maxbug.  The screen is not cleared properly, and Maxbug does
not respond to commands (except with "HUH?").  When I run without Maxbug,
I can fill the ramdisk completely without any problem.

Does anyone know how Maxbug decides to place its data?  Is there any way
that other code can detect that Macsbug is running, and avoid the contested
memory area?
-- 
Ephraim Vishniac
  [apollo, bbncca, cadmus, decvax, harvard, linus, masscomp]!wanginst!vishniac
  vishniac%Wang-Inst@Csnet-Relay