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Introduction
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I am re-entering this information on the Database, after 16 months of testing my BW G3 clocked from 350 Mhz to 400 Mhz. (I have decided to downgrade to the original clock setting of 350Mhz, read on, specially if you run LinuxPPC or similar) Oh boy, this is long, but well worth it...
Back in April 1999 when I purchased by BW 350, I immediatley clocked it up to 400 Mhz. The Mac has behaved like a champ ever since, with only random crashes that I cannot attribute to the clocking itself, but rather the MacOS or some other software issue (the typical sporadic crashes, nothing special, really...) I constantly run very CPU intensive tasks on this mac (Seti, Quake3, UT, etc) and it performs as expected.
We want LinuxPPC
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Well, since my wife is the linux type, I decided to dedicate one of the internal Hard Drives to Linux (10 Gig) and the other to MacOS (40 Gig). We've had a lot of experience installing LinuxPPC on Macs before, including LinuxPPC 1st release, LinuxPPC 1999, and LinuxPPC2000. (On Beige G3 and BW G3)
Problems Begin
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We had been using LinuxPPC2000 for over 4 months now, with excellent results and performance. However, we had never tried compiling anything. Instead, we prefere downloading pre-compiled binaries to spare the hassle.
Just last week my wife tried compiling MySQL (Database program), which is rather large. This is where problems began. The GCC compiler would begin compiling (after 'make' command was issued) and abort half way through the process, with either 'signal 11', 'signal 6', 'signal 7' or ultimatley a severe hard crash (frozen mouse, on Linux?! yikes...) We tried compiling several different packages, dozens of times each in some cases, and always getting these errors.
To make things worse, it would not always abort on the same spot. Actually, commading Linux to continue compiling (re-issuing 'make' would continue compiling successfuly for a few seconds and aborting again)This started hinting us at a hardware issue , although we wanted to believe it was software related. The memory was our first suspect.
We're not alone!
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My wife did an excellent job at finding people that have been having trouble compiling under Linux, with these same specific errors that GCC was generating. She could not find a single Mac user with these problems, but she did find a page dedicated to dealing with this exact problem, on PC hardware. It is located at:
http://www.bitwizard.nl/sig11/
...and knowns as "The Sig11 FAQ". The FAQ deals with possible causes of the sig11 crash, and how to deal with it. This is an EXCELLENT read for anyone having general and misterious problems with their computer, EVEN if you don't run Linux. Really.
We read this throughly, and realized almost everything explained here applied to our Mac. It is definitely biased towards hardware related issues (95%), so we where ready for the worse.
Back to 350, baby
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We quickly discarded memory as the culprit, by testing 2 out of 4 modules at a time.
The FAQ mentions overclocking as a possible cause of the compiling error. So I placed the jumpers back to the original setting, and booted at 350 Mhz for the first time in 16 months. Argh! To my surprise, the compilation took place flawlessly. We continued compiling other stuff that had failed before, and also worked out fine. Everything compiles perfectly, not a single abort, error, or crash. And remember, these same procedures would ALWAYS fail under 400 Mhz configuration, repeatedly.
The FAQ goes on explaining that the compilation process is very strict and hardware demanding, in terms of CPU, memory, bus, and cache. It basically states that the best integrity check for harware, in general, is performing a large compilation. I accept that statement blindly as a rule of thumb, because absolutely non of the tests I have performed on the MacOS have failed, this included mounting of extremely large .smi images, among others.
Conclusion
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Well, my conclusions are:
a) If you are getting compile errors under Linux, and you have clocked your CPU, downclock and see if this is the culprit. It was for us, and it has been for many people on the 'darker' side.
b) Some apparent 'software specific errors' could be hardware related. Read the FAQ, I'm telling you!
c) I need to get a new, faster, ZIF upgrade now ;)
-Cristian
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