Monthly Archives: June 2018

ANOMALY: meaningless REX prefix used

Posted on June 20, 2018 by Michal Necasek

While trying to get work done, I was confronted by several disturbing messages printed on the console of a 64-bit Windows 7 system: [0x7FEEFEFAAA0] ANOMALY: meaningless REX prefix used [0x7FEEFEE48C0] ANOMALY: meaningless REX prefix used [0x7FEEFEE54B0] ANOMALY: meaningless REX prefix used This … Continue reading →

Posted in Bugs, Debugging | 9 Comments

A Brief History of Unreal Mode

Posted on June 15, 2018 by Michal Necasek

After a run-in with a particularly crazy manifestation of unreal mode (Flat Assembler, or fasm), I decided to dig deeper into the history of this undocumented yet very widely used feature of 32-bit x86 processors. For the purposes of this … Continue reading →

Posted in 386, Corrections, Microsoft, PC history, Undocumented | 47 Comments

USB 0.9

Posted on June 2, 2018 by Michal Necasek

A couple of months ago I lamented the fact that historic USB documentation appears to have vanished from the face of the Earth. Today I finally found one such document, the USB 0.9 specification from April 13, 1995, published almost … Continue reading →

Posted in Documentation, PC history, USB | 30 Comments