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- To: email@example.com
- Subject: Re: PowerBook170
- From: Gary Byers <gb>
- Date: Tue, 31 Mar 92 13:21:19 EDT
- Cc: firstname.lastname@example.org, email@example.com
- In-reply-to: <9203311607.AA05837@MEDG>; from "firstname.lastname@example.org" at Mar 31, 92 11:07 am
> 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.