🚀 go-pugleaf

In article <1990Dec28.210731.10685@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes:
   In article <1990Dec18.234020.2491@uoft02.utoledo.edu> stx0641@uoft02.utoledo.edu writes:
   >	My friend told me that we can use 16Mhz 80386 DX CPU on 25Mhz 80386 DX
   >motherboard.  Is it reliable?  Will it destroyed chips on the motherboard?

   It is unlikely to do any damage.  But it will not be reliable.  Chips will
   often run faster than their rated speed, when the temperature and the power
   voltage and the surrounding circuitry and the phase of the moon are all
   just right.  But there is no way to tell whether the chip is just barely
   working, so that the slightest change in conditions will start producing
   intermittent random failures.

Actually, if it boots, it'll probably be (reasonably) reliable.  The 80386
is such a complicated beastie that if it's even slightly flaky, it'll probably
crash immediately.  It'll probably run hotter 'en 'ell, though.

Now, the problem with Taiwanese 25MHz boards that are built with 20MHz chips
is that since the support chips (you know, like the ones that C&T makes) are
also rated for the lower speed, all the timings are screwed up.  It won't
mean much if you only use a ST-506 hard disk, but you probably won't get an
Adaptec SCSI to run, since they try to use the bus to a maximum efficiency !

Also, I've seen several IDE hard disks which intermittently scrambled the
data they were reading/writing, when run on a cheapo 25MHz machine.  No,
they didn't give a CRC error or anything, they screwed up on the data bus
side.  This is again easy to ignore on a low-tech operating system like DOS,
where you'll notice the problem only when your FAT gets hit, but Unix won't
even get halfway up on machines like this.

Caveat Emptor!
"I've seen things... you people couldn't imagine.  Attack ships on fire off
the shoulders of Orion.  I've watched C-beams glitter in the dark near the
Tannhauser gates.  All those moments will be lost... like tears in the rain."
--
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