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The Beige Years

How a Store Display PC Exposed Intel's Pentium Secret

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The Pentium FDIV bug cost Intel $475 million, and Intel had found it months before a professor did.

Here is how one Sunday e-mail, CNN and IBM forced Andy Grove into a public apology and a recall nobody wanted.

Subject
The Pentium FDIV bug, 1994
Chapters
8
Sources
8
Credits
51
Corrections
0

Sources

8
  • Article8

The sources the story leans on most, primary sources first. Read dates are when the page was consulted; the live page may have changed since.

  1. [1]
  2. [2]
  3. [3]
  4. [4]
  5. [5]
  6. [6]
  7. [7]
  8. [8]

Image & music credits

51
  • License unknown37
  • CC BY-SA 3.06
  • CC BY-SA 4.04
  • GNU FDL 1.21
  • CC BY-SA 2.01
  • CC BY 3.01

48 photos, 1 font, 1 music track, from the hosts linked below. Each file name links to the file's page, which carries the full license terms.

#UseFileAuthorLicense
1 Photo 3,5-zoll-diskette Verbatim HD Vorderseite 2021 (cropped).jpg VSchagow CC BY-SA 4.0
2 Photo https://commons.wikimedia.org/wiki/Special:FilePath/Pentium-60-front.jpg commons.wikimedia.org License unknown
3 Photo https://static.tedium.co/uploads/Thomas-Nicely-University-of-Lynchburg.jpg Thomas Nicely, 1984 (University of Lynchburg, via Tedium) License unknown
4 Photo https://commons.wikimedia.org/wiki/Special:FilePath/KL Intel Pentium P5.jpg commons.wikimedia.org License unknown
5 Photo https://cdn.prod.website-files.com/5e94942247047e79b85db6b3/5f0dbde322dd5d146f60773d 2-celebrate-andy-grove-intel-visionary.png Andy Grove holding a chip, 1990s (Lossless Group) License unknown
6 Photo https://commons.wikimedia.org/wiki/Special:FilePath/KL Intel Pentium A80501.jpg commons.wikimedia.org License unknown
7 Photo Intel Pentium arch.svg Appaloosa CC BY-SA 3.0
8 Photo https://commons.wikimedia.org/wiki/Special:FilePath/Pentium-60-front.jpg commons.wikimedia.org License unknown
9 Photo Ic-photo-Intel--A80501-66--(Pentium-CPU).JPG Myself User:ZyMOS CC BY-SA 4.0
10 Photo KL Intel Pentium P5.jpg Konstantin Lanzet GNU FDL 1.2
11 Photo https://commons.wikimedia.org/wiki/Special:FilePath/Intel Pentium A80501 66 SX950-layout.jpg commons.wikimedia.org License unknown
12 Photo https://static.righto.com/images/pentium-fdiv/table-labeled.jpg Ken Shirriff, 'Intel's $475 million error: the silicon behind the Pentium division bug', righto.com, December 2024 License unknown
13 Photo intel white paper 1994-11-30 p10.png Intel white paper (Sharangpani and Barton), 30 November 1994 License unknown
14 Photo https://static.righto.com/images/pentium-fdiv/bounds2.jpg Ken Shirriff, 'Intel's $475 million error: the silicon behind the Pentium division bug', righto.com, December 2024 License unknown
15 Photo https://commons.wikimedia.org/wiki/Special:FilePath/KL Intel Pentium P5.jpg commons.wikimedia.org License unknown
16 Photo intel white paper 1994-11-30 p08.png Intel white paper (Sharangpani and Barton), 30 November 1994 License unknown
17 Photo https://static.righto.com/images/pentium-fdiv/pla-zoom.jpg Ken Shirriff, righto.com License unknown
18 Photo KL Intel Pentium A80501.jpg Konstantin Lanzet CC BY-SA 3.0
19 Photo mpr how bad is the pentium fpu bug 1994-12-26 p1.png Microprocessor Report (Linley Gwennap), 26 December 1994 License unknown
20 Photo https://static.righto.com/images/pentium-fdiv/pla-top-labeled.jpg Ken Shirriff, righto.com License unknown
21 Photo https://archive.org/details/bub gb jDgEAAAAMBAJ/page/n0 InfoWorld, 19 September 1994 (Internet Archive scan) License unknown
22 Photo https://archive.org/details/undocdos2ed/page/n0 Internet Archive scan License unknown
23 Photo https://commons.wikimedia.org/wiki/Special:FilePath/Pentium-60-back.jpg Pentium-60-back.jpg, Wikimedia Commons License unknown
24 Photo https://commons.wikimedia.org/wiki/Special:FilePath/Stanford University Arches with Memorial Church in the background.jpg Stanford University Arches with Memorial Church in the background, Wikimedia Commons License unknown
25 Photo Intel HQ exterior 5.JPG BrokenSphere CC BY-SA 3.0
26 Photo https://archive.org/details/bitsavers microsoftwdocumentedWindows1992 67697945/page/n0 Internet Archive scan License unknown
27 Photo Walt Mossberg at TPS09 (cropped).jpg Andrew Feinberg CC BY-SA 3.0
28 Photo intel white paper 1994-11-30 p01.png Intel white paper (Sharangpani and Barton), 30 November 1994 License unknown
29 Photo intel white paper 1994-11-30 p15.png Intel white paper (Sharangpani and Barton), 30 November 1994 License unknown
30 Photo Intel Headquarters in 2023.jpg Coolcaesar CC BY-SA 4.0
31 Photo Personal computer collection rack - Computer History Museum (2007-11-10 21.23.48 by Carlo Nardone).jpg Carlo Nardone from Roma, Italy CC BY-SA 2.0
32 Photo The new york times building in new york city.jpg Alterego CC BY-SA 3.0
33 Photo Wall Street Journal building.jpg PumpkinSky CC BY-SA 3.0
34 Photo https://static.righto.com/images/pentium-fdiv/apology.jpg Intel's apology advertisement in the Financial Times, December 1994 (photograph: Ken Shirriff, righto.com) License unknown
35 Photo mpr how bad is the pentium fpu bug 1994-12-26 p4.png Microprocessor Report (Linley Gwennap), 26 December 1994 License unknown
36 Photo https://static.tedium.co/uploads/Pentium-Floating-Point-Keychain.jpg Intel Pentium keychain, Computer History Museum catalog 102711135 (via Tedium) License unknown
37 Photo https://static.tedium.co/uploads/Thomas-Nicely-University-of-Lynchburg.jpg Thomas Nicely, 1984 (University of Lynchburg, via Tedium) License unknown
38 Photo https://i.ebayimg.com/images/g/xKsAAeSwWIVp1A60/s-l1200.webp Packard Bell Force 447CD with an Intel Pentium (eBay listing photo) License unknown
39 Photo https://cdn.mos.cms.futurecdn.net/NH3GkJpFYyVAjqEhmGR7Da.png Ken Shirriff's Pentium die photo, via Tom's Hardware (2024) License unknown
40 Photo https://commons.wikimedia.org/wiki/Special:FilePath/Lynchburg College.jpg Lynchburg College Grounds, Wikimedia Commons (2009) License unknown
41 Photo https://guidebookgallery.org/pics/gui/applications/office/calculator/win31.png guidebookgallery.org License unknown
42 Photo https://commons.wikimedia.org/wiki/Special:FilePath/Intel HQ.jpg Intel HQ in Santa Clara, Wikimedia Commons (2011) License unknown
43 Photo https://commons.wikimedia.org/wiki/Special:FilePath/Pentium 60 SX948 gold front.jpg Andrzej w k 2, Wikimedia Commons License unknown
44 Photo https://static.righto.com/images/pentium-fdiv/pla-labeled.jpg Ken Shirriff, righto.com License unknown
45 Photo https://static.righto.com/images/pentium-fdiv/pla-lhs.jpg Ken Shirriff, righto.com License unknown
46 Photo https://commons.wikimedia.org/wiki/Special:FilePath/The Wall Street Journal Logo.svg?width=2000 The Wall Street Journal masthead logo, Wikimedia Commons License unknown
47 Photo https://commons.wikimedia.org/wiki/Special:FilePath/Intel Pentium A80501 66 SX950.JPG Intel Pentium A80501 66 SX950, Wikimedia Commons License unknown
48 Photo https://static.righto.com/images/pentium-fdiv/pla-silicon-right.jpg Ken Shirriff, righto.com License unknown
49 Font https://int10h.org/oldschool-pc-fonts/ IBM VGA 8x16 from VileR's Ultimate Oldschool PC Font Pack CC BY-SA 4.0
50 Music Pamgaea (ISRC USUAN1300036).mp3 "Pamgaea" by Kevin MacLeod (incompetech.com) CC BY 3.0

Video by KoolShooters on Pexels

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