Category Archives: Intel

There’s More to the 286 XENIX Story

It turns out that there is a rather interesting story behind the 286 XENIX incompatibility with 386 and later processors. Here’s roughly what happened in chronological order. In 1982, Intel released the iAPX 286 processor, later known as the 80286 or simply 286. This … Continue reading

Posted in 286, 386, Intel, Microsoft | 34 Comments

PCI Corner Case

Last weekend I had the pleasure of debugging a curious case of older PCI configuration code (circa 2005) failing on newer (post-2010) hardware. The code was well tested on many 1990s and 2000s PCs (and some non-PCs) with PCI/AGP/PCIe and never … Continue reading

Posted in Bugs, Intel, PCI | 1 Comment

Top of the Class 478

So I have that old Intel D865PERL board, which is a Socket 478/AGP board. There’s a 3.2 GHz Northwood in it but of course I was wondering, what’s the fastest CPU this board supports? And it turns out to be a … Continue reading

Posted in Intel, PC hardware, PC history, Pentium 4 | 3 Comments

Mystery NetBurst

Some time ago, a mysterious CPU showed up at the OS/2 Museum: It is a Socket 775 CPU with a Pentium 4 label and the following markings: 3.73 GHZ/1M/1066/A4. In other words, 3.73 GHz clock speed, 1 MB L2 cache, … Continue reading

Posted in Intel, Pentium 4 | 20 Comments

Intel OverDrive Part III: Pentium II OverDrive

Pentium II OverDrive The Pentium II OverDrive, released in August 1998, was the swan song of the OverDrive product line. It is suitable for Socket 8 systems as an upgrade of 150-200 MHz Pentium Pro processors. Only one model was sold with … Continue reading

Posted in Intel, Pentium II, Pentium Pro | 19 Comments

Intel OverDrive Part II: Pentium OverDrive

The Pentium OverDrive is notable for supporting three physically different sockets (that’s not counting the Pentium II OverDrive). The Pentium OverDrive product was sold in variants suitable for Socket 2/3 (486 systems), Socket 4 (early Pentium systems), and Socket 5/7 … Continue reading

Posted in 486, Intel, PC history, Pentium | 21 Comments

Better Late Than Never

Better late than never, although in this instance, it’s really really late—about thirty years late. In the world of computing, that is eternity. The talk is about the new CR4.UMIP control bit documented in the latest (revision 58) Intel SDM, … Continue reading

Posted in 286, Intel, x86 | 8 Comments

NT 3.1 SMP

Generic x86 multiprocessing, Summer 1994 edition. There’s not much to say: Yep, that’s NT 3.1 running in a VM, and it sees two processors. Remember, you saw it here first!

Posted in Intel, NT, SMP | 61 Comments

Missing Intel SDM Documents

I’ve been trying to complete my archive of Intel SDM documents circa 2000 and later. I have most of the editions archived but a few are missing. Readers of this blog could have something stashed away too, so perhaps someone … Continue reading

Posted in Documentation, Intel | 11 Comments

Lies, Damn Lies, and Wikipedia

While researching the history of 486s for a previous article, I came across a fascinating Wikipedia entry and its associated talk page. It’s a nice showcase of inmates running the asylum, and a reminder that Wikipedia can’t be considered an authoritative … Continue reading

Posted in 486, Intel, PC history | 25 Comments