Author Archives: Michal Necasek

Floppy Capacity Math

Posted on June 8, 2014 by Michal Necasek

After more or less accidentally coming across a BBS listing of various high-capacity floppy formatting programs, I began wondering: How much data can really be stored on a diskette in a PC floppy drive? And what’s the relationship between formatted … Continue reading →

Posted in Floppies, PC hardware | 41 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 | 54 Comments

PC Tech Journal

Posted on May 29, 2014 by Michal Necasek

One of the better PC magazines back in the day (that is, in the 1980s) was PC Tech Journal (or PCTJ for short), a sister periodical of PC Magazine published by Ziff-Davis. While PC Magazine was targeted at the general computer-buying … Continue reading →

Posted in PC history, PC press | 7 Comments

IBM Power Series Exotica

Posted on May 23, 2014 by Michal Necasek

One might think that for example a ThinkPad Power Series 850 is an uncommon system, but such things are relative. The OS/2 Museum recently learned of not just one but two very rare Power Series systems, one of which is virtually a … Continue reading →

Posted in IBM, PowerPC | 7 Comments

Timing In Software Is Too Hard?

Posted on May 16, 2014 by Michal Necasek

I recently attempted to install RedHat Linux 3.0.3 (that’s the one from 1996, not RHEL 3.0) in VirtualBox. I thought I’d use the BusLogic SCSI emulation and the newer 1.3.57 Linux kernel. It did not work at all. The problem … Continue reading →

Posted in Bugs, BusLogic, Linux, SCSI | 32 Comments

Microsoft OS/2 1.3… But Which One?

Posted on May 7, 2014 by Michal Necasek

A recent inventory at the OS/2 Museum revealed that two seemingly identical sets of Microsoft OS/2 1.30.1 disk images were in fact not identical at all. Probably thanks to the twilight status of OS/2 at Microsoft in the days of OS/2 1.3, Microsoft … Continue reading →

Posted in LAN Manager, Microsoft, OS/2 | 26 Comments

Have You Seen This Board?

Posted on May 2, 2014 by Michal Necasek

The OS/2 Museum recently acquired this mystery 386 board (click on the image to see a high-resolution photo): This is in theory a killer 386 board: onboard Am386DX-40, a socket for a replacement 386 or 486DLC processor, a FPU socket, 256KB cache, … Continue reading →

Posted in 386 | 23 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

OEM MS OS/2: 1987-1990

Posted on April 18, 2014 by Michal Necasek

When Microsoft started offering OS/2, the arrangement was roughly similar to how DOS 3.3 had been handled: Microsoft and IBM jointly developed the code, IBM maintained its own version, and Microsoft licensed an “adaptation kit” to OEMs. While the IBM … Continue reading →

Posted in Microsoft, OS/2 | 18 Comments

Multitasking MS-DOS 4.0, Goupil OEM

Posted on April 9, 2014 by Michal Necasek

The recently unearthed copy of the near-mythical Multitasking (aka European) MS-DOS 4.0 clearly did not want to be alone. James Lariviere, a kind reader of this blog, provided a disk image of multitasking DOS 4 which was released in 1986 … Continue reading →

Posted in DOS, Microsoft, OS/2 | 29 Comments