Category Archives: Intel

The i860 Conspiracy

Posted on November 10, 2019 by Michal Necasek

I’ve been thinking of acquiring a board with the Intel 860 (Colusa) chipset. This chipset is historically interesting because it was Intel’s first chipset for NetBurst Xeons, and–at least according to Intel–the only chipset that supports the original Foster Xeon … Continue reading →

Posted in Intel, PC hardware, PC history | 15 Comments

More About That Strange Pentium 4

Posted on October 26, 2019 by Michal Necasek

A few years ago I wrote about a strange NetBurst processor with SL7HY S-spec that landed at the OS/2 Museum. After renewed reader interest I pulled it out of the closet and tested the processor again. A collection of miscellaneous … Continue reading →

Posted in Intel, PC hardware, PC history, Pentium 4, Undocumented | 32 Comments

Where’s Intel When You Need Them?

Posted on August 21, 2019 by Michal Necasek

As readers of this blog know, I’m a long-time happy user of Intel desktop boards. I’ve now been using Intel boards for my main machine continuously for over 15 years (D865PERL, DG965RY, DQ67OW, DQ77CP); I have some fond and some … Continue reading →

Posted in Intel, PC hardware | 16 Comments

A Piece of History

Posted on November 21, 2018 by Michal Necasek

A few months ago I received a well-used but not abused copy of Rakesh K. Agarwal’s book 80×86 Architecture and Programming (Volume II): Architecture Reference, published by Prentice Hall in 1991. This is an unusually well-informed book, no doubt because … Continue reading →

Posted in 386, Books, Cyrix, Intel, PC architecture, PC history | 6 Comments

ICEBP Finally Documented

Posted on May 25, 2018 by Michal Necasek

After more than 30 years, Intel finally documented the INT1 instruction, also known as ICEBP (opcode F1h), in the latest (May 2018, -067) edition of the SDM. This was probably forced by security concerns, because from a security standpoint, having … Continue reading →

Posted in 386, Documentation, Intel, Undocumented | 14 Comments

Undocumented RDTSC

Posted on April 27, 2018 by Michal Necasek

The other day I wrote a simple DOS program which used the RDTSC instruction in order to obtain precise time measurements (of how long it takes a PS/2 keyboard to send data; more about that some other time). The 16-bit … Continue reading →

Posted in Documentation, Intel, Pentium | 15 Comments

Undocumented 8086 Opcodes, Part I

Posted on December 27, 2017 by Michal Necasek

This is a guest post by Raúl Gutiérrez Sanz This multi-part document is about undocumented 8086 processor opcodes and their behavior. Most of the document will likely apply to the 8088 processor as well, but this has not been verified. … Continue reading →

Posted in 8086/8088, Intel, Undocumented | 13 Comments

How Apple Created Hackintosh, Part II

Posted on December 20, 2017 by Michal Necasek

There is every indication that throughout the early 2000s, Apple internally built and ran all of OS X on x86 PCs (it’s also something Steve Jobs himself mentioned in 2005). Otherwise why would Apple have x86 drivers for AC’97 audio … Continue reading →

Posted in Apple, Intel, OS X, PC history, Pre-release | 10 Comments

HTT Means Hyper-Threading, Right?

Posted on December 11, 2017 by Michal Necasek

In a logical, ordered world, the HTT bit in CPUID would indicate a processor with Hyper-Threading Technology enabled. But of course the world with Intel inside is anything but logical. The actual meaning of the HTT bit changed several times … Continue reading →

Posted in Documentation, Intel, Pentium 4 | 13 Comments

How Apple Created Hackintosh, Part I

Posted on November 29, 2017 by Michal Necasek

At a developer conference in June 2005, Apple announced that OS X will transition from PowerPC to Intel processors. The first Intel Macs (sometimes nicknamed “Mactels”) were introduced several months later, in January 2006. The announcement generated significant interest in … Continue reading →

Posted in Apple, Intel, PC history, Pre-release | 10 Comments