Author Archives: Michal Necasek

What a Coincidence

Posted on March 11, 2017 by Michal Necasek

Timeline: Mid-1988: SCO 386 Xenix 2.2.3 is released 1996 (probably): Someone dumps the 386 Xenix 2.2.3 disks, but enough sectors are missing that the OS is impossible to install January 3rd, 2013: OS/2 Museum posts about the damaged Xenix dump February … Continue reading →

Posted in PC history, Xenix | 1 Comment

Oldest Surviving 386 PC OS?

Posted on March 9, 2017 by Michal Necasek

Four years ago, the Xenix 2.2.3 mystery cropped up (twice). The issue has been revisited and thanks to Michael Casadevall, an enthusiastic reader, came to a happy conclusion: 386 Xenix version 2.2.3 was finalized in late June 1988 (the newest … Continue reading →

Posted in 386, Microsoft, SCO, UNIX, Xenix | 24 Comments

More Data on CF to IDE to SCSI

Posted on March 6, 2017 by Michal Necasek

To get a better picture of the performance of the CF to IDE to SCSI solution, I moved the Adaptec 1542C into one of my favorite boards, the Alaris Cougar with a classic Intel 486 DX2 OverDrive CPU. For a … Continue reading →

Posted in 486, CompactFlash, IDE, Storage | 16 Comments

Resetting Disks Is Hard

Posted on February 26, 2017 by Michal Necasek

After digging through BIOS listings and disassembling the Adaptec 1542C BIOS as well as the PC DOS 2000 boot sector, it’s clear why the floppy-less SCSI boot does not work on my test system. It’s because disk reset done by the boot … Continue reading →

Posted in BIOS, Bugs, SCSI | 22 Comments

Booting Is Hard

Posted on February 23, 2017 by Michal Necasek

So I had this brilliant idea of using SCSI drives with old 286/386/486 boards which have old BIOSes that can’t handle IDE drives bigger than 500-ish megabytes. The SCSI HBA is the first one I happened to grab, an Adaptec 1542C … Continue reading →

Posted in 386, BIOS, CompactFlash, DOS, SCSI | 21 Comments

Spot the Fakes

Posted on February 17, 2017 by Michal Necasek

Would you believe that besides all the other Made in China fake brand-name items, there are also fake memory modules? Of course you would! At least Kingston and Samsung modules have been seen in the wild; the Kingston ones are … Continue reading →

Posted in DDR RAM, Fakes | 17 Comments

IBM XENIX 1.0 Incompatibility Details

Posted on February 7, 2017 by Michal Necasek

Some time ago I wrote about IBM PC XENIX 1.0 and why it won’t work on 386 and later processors. Thanks to a kind reader, I’ve been able to analyze the object files used to link the kernel, and I believe … Continue reading →

Posted in 286, 386, Microsoft, Xenix | 21 Comments

Top of the Class 478

Posted on January 26, 2017 by Michal Necasek

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 | 8 Comments

More Peripherals

Posted on January 20, 2017 by Michal Necasek

Remember this post from a while ago? Several new peripherals have turned up, but what are they? This time, the manufacturer names vanished together with the model numbers, but it shouldn’t be too hard. Do you know these peripherals? PS: … Continue reading →

Posted in MIDI, Sound | 11 Comments

Shiniest x86 Chip

Posted on January 16, 2017 by Michal Necasek

While there have been many shiny new chips in the metaphorical sense, x86 (and x87) chips have never been known to be literally shiny. The typical packaging is ceramic or some form of brushed metal, and neither of these surfaces is … Continue reading →

Posted in 386, C&T, PC hardware | 14 Comments