Re: PowerBook170

[Gary Byers <gb>]

> 
> This is the famous "Rest" feature of the PB, which can be disabled in
> the dialog you get by Option-clicking on the top text line in the
> "Portable" control panel.  It's all documented in the "Using Power
> Efficiently" chapter of the manual (p. 102 in mine).
> 

People using MCL on PowerBook 170s should be aware of a bug related to
"rest" mode on that platform.  The bug causes floating-point state to
be lost when the PB enters rest mode; a consequence is that floating-point
exceptions (such as overflow and divide-by-zero) go undetected.

We've reported the bug to the responsible parties, but haven't yet heard
when/how the fix will be made available.  The workaround is to disable
the "rest" feature as indicated above.  Note that disabling "rest" mode 
will have a negative effect on battery life when the PowerBook isn't 
plugged in to another power source, so the other workaround is to either
not generate exceptional floating-point conditions or to not depend on
their ability to cause exceptions to be generated.