Author Archives: Michal Necasek

386 Cache Coherency

Posted on April 8, 2020 by Michal Necasek

I’ve been slowly chewing my way through U.S. Patent 5,724,549, titled Cache Coherency without Bus Arbitration Signals, initially filed by Cyrix Corporation in 1992 and published in 1998 (when it was utterly irrelevant, but such is the life of patents). … Continue reading →

Posted in 386, Cyrix, PC architecture, PC history | 18 Comments

Linux 2.4 APIC Hang

Posted on March 16, 2020 by Michal Necasek

The other day I set out to install SuSE Linux 7.3 (Linux 2.4.10 kernel) in a virtual machine, primarily with the goal of evaluating if the included MARS_NWE NetWare emulator is any good. But I couldn’t get anywhere–the boot floppy … Continue reading →

Posted in Bugs, Linux, PC hardware | 16 Comments

OS/2 1.3 on a “Large” Disk

Posted on March 6, 2020 by Michal Necasek

In response to a reader question, I started wondering how difficult it actually is to install OS/2 1.3 on a “big” hard disk, where “big” is defined as more than about 500 MB. In an attempt to reduce the number … Continue reading →

Posted in BusLogic, OS/2, PC history, Storage | 16 Comments

EMM386 and VDS: Not Quite Working

Posted on February 26, 2020 by Michal Necasek

The other day I set out to solve a seemingly simple problem: With a DOS extended application, lock down memory buffers using DPMI and use them for bus-mastering (BusLogic SCSI HBA, though the exact device model isn’t really relevant to … Continue reading →

Posted in Bugs, Development, DOS Extenders | 2 Comments

A Brief Visit to Disk Geometry Hell

Posted on February 20, 2020 by Michal Necasek

Several weeks ago I thought I’d install NetWare 3.12 in a virtual machine using the BusLogic SCSI controller emulation. While configuring a 1.5 GB virtual drive, I thought I should be safe and not run into any trouble with a … Continue reading →

Posted in BusLogic, IBM, NetWare, PC architecture, Storage | 32 Comments

Emulating EtherLink

Posted on January 31, 2020 by Michal Necasek

Spurred by the discovery of a pre-release OS/2 NetWare Requester from early 1988 with a very thin selection of drivers, several months ago I decided to write emulation of the classic 3Com 10Mbps Ethernet 3C501 card, also known as EtherLink. … Continue reading →

Posted in 3Com, Networking, PC hardware, PC history, Virtualization | 33 Comments

1987 Networking: ELS NetWare 286 Level I 2.0a

Posted on January 24, 2020 by Michal Necasek

A rare find recently turned up: NetWare from 1987, specifically the low-end ELS variant of NetWare 286 version 2.0a (ELS may be claimed to mean Entry Level System or maybe Entry Level Server, but at least originally it stood for … Continue reading →

Posted in 286, 3Com, Kryoflux, NetWare, Networking | 29 Comments

Another Strange 286 Board

Posted on January 20, 2020 by Michal Necasek

The OS/2 Museum sometimes seems to have a knack for acquiring hardware so obscure that it cannot be even identified. One of the more recent arrivals was a seemingly typical Baby AT 286 board with an 8 MHz CPU. The … Continue reading →

Posted in 286, PC hardware, PC history | 27 Comments

More Fun with ISA DMA

Posted on January 13, 2020 by Michal Necasek

A reader comment on a previous post on ISA DMA pointed out that UMBPCI (or rather the DMACHK utility distributed with it) does something unusual with regard to ISA DMA. There was a suspicion of somehow accomplishing the mythical memory-to-memory … Continue reading →

Posted in PC architecture, PC hardware, Software Hacks | 8 Comments

MS OS/2 SDK Document Dump

Posted on January 3, 2020 by Michal Necasek

The Microsoft OS/2 1.0 SDK library section got a big fat update. Over the holidays I managed to finalize and upload about 25 PDFs, some of which have been lying on my NAS in 98% completed state for almost 10 … Continue reading →

Posted in Documentation, Microsoft, OS/2 | Leave a comment