Category Archives: Intel

Solaris 2.6, 7, and 8 Crashes on Pentium 4 and Later

Posted on February 27, 2015 by Michal Necasek

A blog reader recently pointed to an interesting problem which affects older Solaris releases on certain systems. The symptoms (crash/reboot) may at first glance look like the previously described problem which affected Solaris 2.5.1 and 2.6, but both the cause and … Continue reading →

Posted in Bugs, Debugging, Intel, Solaris | 2 Comments

Curious Instructions

Posted on December 13, 2014 by Michal Necasek

Years ago, Geoff Chappell (the author of DOS Internals, among other things) published an article about mysterious instructions that Microsoft’s LINK knows but Intel’s documentation is silent about. The fourteen listed instructions were: LOADALL, CFLSH, WRECR, RDECR, SVDC, RSDC, SVLDT, … Continue reading →

Posted in Documentation, Intel, x86 | 11 Comments

Forward Compatibility, Landmines

Posted on September 20, 2014 by Michal Necasek

Several years ago, after attempting to get a very old 286 version of Xenix running in a VM, I concluded that it was probably incompatible with any 386 and later processor. Recently I revisited this issue and examined the problem … Continue reading →

Posted in 286, Intel, Xenix | 32 Comments

IBM Blue Lightning: World’s Fastest 386?

Posted on August 22, 2014 by Michal Necasek

One of the OS/2 Museum’s vintage boards is a genuine Made in U.S.A. Alaris Cougar. These boards were produced by IBM for Alaris and are a bit unusual: There’s a small IBM DLC3 processor in plastic package soldered on board, … Continue reading →

Posted in 386, IBM, Intel, PC hardware, PC history | 62 Comments

Intel 287XL… From 1986? Or 1996?

Posted on June 14, 2014 by Michal Necasek

Many or most readers of this site probably know that most chips (and PCBs) have the date of manufacture stamped on them, almost always indicating the year and week (usually not the actual date) they were made. Especially with PCBs, … Continue reading →

Posted in Intel, PC history | 11 Comments

The IBM PC BIOS and Intel ISIS-II

Posted on May 30, 2014 by Michal Necasek

An interesting question recently popped up: How exactly did IBM build the ROM BIOS for the IBM PC? Knowing what tools were used should make it possible to use the ROM listing published in the IBM PC Technical Reference and … Continue reading →

Posted in BIOS, IBM, Intel, PC history | 44 Comments

From the Annals of Branding

Posted on April 25, 2014 by Michal Necasek

The following picture shows four essentially identical Intel processors in the top row: The real difference is that some of them are fabricated on an older process and thus sport a larger die size than others. (They’re also not all … Continue reading →

Posted in 386, Intel | 14 Comments

Undocumented 8086 Opcodes

Posted on December 21, 2013 by Michal Necasek

A minor mystery recently surfaced while analyzing DOS boot sectors. DOS uses several criteria when deciding whether a boot sector contains a valid BPB, and one of the criteria is (oddly enough) checking whether the first two bytes of the … Continue reading →

Posted in 8086/8088, Documentation, Intel, x86 | 62 Comments

More on LOADALL and OS/2

Posted on October 27, 2013 by Michal Necasek

As previously mentioned, IBM’s OS/2 1.0 and 1.1 used the 286 LOADALL instruction, even on 386 and later processors which do not support it. This was typically solved by BIOS emulation. Now there’s more information about how OS/2 uses LOADALL. … Continue reading →

Posted in IBM, Intel, Microsoft | 31 Comments

LOADALL Strikes Again

Posted on October 18, 2013 by Michal Necasek

A minor mystery recently popped up while running IBM’s OS/2 1.1 (1988), the first OS/2 version with the Presentation Manager GUI. While Microsoft’s and IBM’s releases of OS/2 were fully compatible from application perspective, there were differences in the drivers … Continue reading →

Posted in IBM, Intel, Microsoft, OS/2, x86 | 11 Comments