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Pentium Divider Flaw

wct097

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Feb 28, 2011
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I'm sure everyone in this forum remembers the FDIV flaw. I grabbed this machine out of the back of a pickup just before it got tossed in the dump about 10+ years ago. Neat piece of nostalgia.

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Relatively certain this is legit. The guy who discovered it worked (works?) for a local college. Wonder if it has any value. I've never plugged it in, nor do I know if the processor was replaced as part of the recall.
 
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wct097

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Have not checked the CPU. Not really even sure how to do so. My assumption is that it was replaced.
 

wct097

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Micron

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I'm guessing it was a higher end machine in it's day. Appears to have a SCSI hard drive.

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Chuck(G)

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Have not checked the CPU. Not really even sure how to do so. My assumption is that it was replaced.

Usually, the heatsink is held on with a spring clip. If you don't see any, try unscrewing the fan and see if that gives any clues.

If this is a historic machine, I'd assume that the original chip would be left in.

If it boots Windows, here's an easy test.
 

wct097

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Usually, the heatsink is held on with a spring clip. If you don't see any, try unscrewing the fan and see if that gives any clues.

If this is a historic machine, I'd assume that the original chip would be left in.

If it boots Windows, here's an easy test.

Well, that depends on the good Doctor's thought process at the time. Did he immediately swap in the new chips Intel sent him? He probably used the computer for research (how he found the problem), and would need it functioning properly. Then again, he did sign it several years after the fact.

Will try plugging it in when I get home. I don't have an AT keyboard. Will poke around the office and see if I can find a PS/2-AT adapter somewhere.
 

Neon_WA

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Are the buggy chips worth much? I have a few early P60/P66 chips that might have the bug.

Some are worth $50+ due to their sSpec rarity (not due to FDIV bug) the more common FDIV sSpecs go for $15

I would be interested in what sSpecs you have :)
I have 16 of the 27 production sSpecs (socket 4, 5 & TCP) containing the FDIV bug
 
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Neon_WA

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I'm sure everyone in this forum remembers the FDIV flaw. I grabbed this machine out of the back of a pickup just before it got tossed in the dump about 10-15 years ago. Neat piece of nostalgia.


Wonder if it has any value.

I would think so... it would to me.. as FDIV items is one of my aims in my collecting
The system itself isnt worth much.. but its place in history is its value

There are a few FDIV collectors.. but they keep to just the chips

I live in Australia.. but I have a friend in Oregon that ships items to me that I buy off US ebay
Will cost me a mint to ship (any idea of weight?)

... but if you do consider selling.. let me know
 

Neon_WA

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Where/how do I look up the sSpec?


type the sSpec into identify section on this page
http://www.cpu-world.com/search.html

then click on sSpec for more information particular to that sSpec

but here is a list of all production chips with FDIV


Socket 4
SX753 A80501-60
SX835 A80501-60
SX842 A80501-60
SX926 A80501-60
SZ949 PCPU5V60
SX754 A80501-66
SX828 A80501-66
SX836 A80501-66
SX837 A80501-66
SZ950 PCPU5V66

Socket 5
SX878 A80502-75
SX874 A80502-90
SX879 A80502-90
SX885 A80502-90
SX909 A80502-90
SX921 A80502-90
SX922 A80502-90
SX923 A80502-90
SX942 A80502-90
SX943 A80502-90
SX944 A80502-90
SZ951 PCPU3V90
SX886 A80502-100
SX910 A80502-100
SX956 A80502-100
SX960 A80502-100

TCP
SX951 TT8050275
 
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wct097

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I would think so... it would to me.. as FDIV items is one of my aims in my collecting
The system itself isnt worth much.. but its place in history is its value

What would be the most appropriate way to determine it's value?

I live in Australia.. but I have a friend in Oregon that ships items to me that I buy off US ebay
Will cost me a mint to ship (any idea of weight?)

No clue, but if it came down to it, I could obviously price it.

... but if you do consider selling.. let me know

Will do. My biggest problem there is assessing a value. I think my first step will be to see if I can find an AT keyboard or adapter and see if I can fire it up.

Without the failing chip, it's just another Micron P1 system, it seems to me.

That could very well be the case. Again, I have no basis for estimating what it's value (if any) is. I suppose I could email the professor for details and to verify it's authenticity.
 

Raven

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I recommend powering up the PSU disconnected from the system before powering it up. This way if anything is wrong with the PSU you'll know before you subject the rest of the system to it.
 

Chuck(G)

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No, but most PSUs won't function without a load. Hook an old hard drive or four to one when powering up. Most PSUs will simply die if they're bad. The chances of one actually ruining anything are very small.
 

hargle

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Well, that depends on the good Doctor's thought process at the time. Did he immediately swap in the new chips Intel sent him? He probably used the computer for research (how he found the problem), and would need it functioning properly. Then again, he did sign it several years after the fact.
Wait, are you saying you've got the machine that the bug was originally discovered on? I apparently work with a guy who worked with the guy who discovered how the problem was introduced in a logic lookup table of some sort. Apparently my co-worker's previous co-worker was the one who tracked it down enough for intel to actually verify that there was a problem. It all sounds very urban legend to me, but I suppose if you're in the tech industry the odds of running into someone like this are pretty good...
 
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