News 30-year-old Pentium FDIV bug tracked down in the silicon — Ken Shirriff takes the microscope to Intel's first-ever recall

[Admin]

Ken Shirriff, noted reverse engineer and processor historian, has identified the specific transistors, incorrectly laid, which caused the original Pentium to be recalled at a cost of $475 million.

30-year-old Pentium FDIV bug tracked down in the silicon — Ken Shirriff takes the microscope to Intel's first-ever recall : Read more

 

[Geef]

- The Pentium was made on an 800nm process -
Wow, how the times have changed. Even removing the two zeros doesn't make it even match my phone's processor nm size.

 

[umeng2002_2]

For those too young, 475 million dollars was a lot of money back in the 90s.

 

[magbarn]

For those too young, 475 million dollars was a lot of money back in the 90s.

Still remembering buying my first loaded 1993 Civic EX for $15,000, which is now a $32,000 2024 Civic Touring

- The Pentium was made on an 800nm process -
Wow, how the times have changed. Even removing the two zeros doesn't make it even match my phone's processor nm size.

I still remember my PC Magazine that had a die shot of the first Pentium when it came out and I was drooling while I was gaming on a 386SX overclocked to 20Mhz. Man I'm getting old.

 

[umeng2002_2]

I was too young to care about these chips, and when I was old enough to care, I was too poor to afford Intel CPUs. Ha. But I do remember hearing about this bug.

 

[hotaru251]

Wow, how the times have changed. Even removing the two zeros doesn't make it even match my phone's processor nm size.

I mean in past "nm" use to be actual size but now-a-days its not actually about the size. (thats why different people's "3nm" are different)

 

[abufrejoval]

For those too young, 475 million dollars was a lot of money back in the 90s.

It was also a lot of money in the 1980's, which is when I bought my first PC, an IBM PC-AT clone for the equivalent of $10,000 back then, about the price of a nice used Porsche 911.

But I need it to make money and a Porsche wasn't going to help (I was into programming not pimping).

I also got an 80287 (and Windows 1.0) for free from Intel, when I bought an Intel Above Board with 1.5MB of extra RAM.

That 80287 never miscalculated and even worked with the 80386 a few years later, while Windows 1 was quickly removed from the 20MB hard drive, because just couldn't compete with GEM and disk capacity was precious.

 

[rsquared]

For those too young, 475 million dollars was a lot of money back in the 90s.

Equivalent to a little over a billion dollars now after inflation adjustment.

Intel's bigger problem with the FDIV bug was their terrible handling of it. If they had just admitted they made a mistake it probably would've gone by mostly unnoticed. Instead they responded like Haha, so what, only loser nerds like you would care about that tiny error. Which quickly blew up into a big PR nightmare for them that echoed for years afterward.

 

[SkyBill40]

Intel: It's not a big deal . Don't worry about it.

Mathematicians: Oh, we beg to differ.

** Intel pays $475M **

Also Intel: We're sorry.