OS/2 Museum

ThinkPad 701 Restore Using CF Media

Posted on February 15, 2015 by Michal Necasek

Thanks to a kind reader, the OS/2 Museum obtained a file archive of the ThinkPad 701 recovery CD. The 701C/701CS was also known as Butterfly thanks to its unique folding keyboard.

The recovery tool appears to have been designed for all ThinkPads and desktop PCs that IBM sold during the era (circa 1995). Since the recovery CD was, well, a CD, the software was able to either boot from a specially created floppy in the target system and directly use a built-in CD-ROM, or connect a CD-ROM-less target system (such as the ThinkPad 701) over a parallel (or even serial, if one had a lot of spare time) cable to a host system equipped with a CD-ROM.

Neither of these methods sounded particularly attractive. PCMCIA-attached CD-ROMs are rather exotic, and the files weren’t even on a CD anyway. A parallel cable would have been a possibility, but since the host system needed to run Windows 3.1 (and have a parallel port), this was rejected too. Oh, and the ThinkPad 701 needs a port expander or a special cable to even have a physical parallel port connector, since it is so small.

On the other hand, the ThinkPad 701 has two PCMCIA slots, and both PCMCIA to CF adapters as well as CF cards and microdrives are inexpensive and easy to find. Better yet, with a USB to CF adapter, it’s very convenient to transfer large chunks of data to/from a modern PC or a Mac. How hard would it be to restore the Butterfly using a CF card? Not too hard. Continue reading →

Posted in IBM, ThinkPad | 23 Comments

Demented Board

Posted on January 31, 2015 by Michal Necasek

Last week I encountered a problem that I have never seen before with a recently acquired Socket 7 motherboard. The board was a Gigabyte GA-586HX (Rev. 1.58), a relatively uninteresting older Socket 7 board based on the well-regarded Intel 430HX chipset.

Apart from automatic voltage detection, the one distinguishing feature of this board is six memory slots rather than the usual four. That makes memory upgrading easier, although in order to get the full 512MB, one would still need at least two of the somewhat hard to find 128MB SIMMs.

What made this particular board much more interesting was that although it wasn’t in original packaging and had memory and CPU installed (four 4MB SIMMs—worthless; a K5 PR133 “goldcap” CPU—at least interesting), it looked completely unused. No signs of wear, no discoloration, and rather tellingly, no dust.

The board as such appeared to work well, but it had one very strange problem: It wouldn’t remember any BIOS settings. No matter what I changed in the setup, on next boot the old settings were back. The only thing that I could change was the date and time. Continue reading →

Posted in Bugs, PC hardware | 14 Comments

Windows 3.0 DR 1.14, February 1989

Posted on January 16, 2015 by Michal Necasek

Another rather interesting software artifact surfaced just recently, after more than 25 years since its release: Windows 3.0 Debug Release 1.14 (further referred to as DR 1.14) from February 1989.

This was an alpha version only provided to select ISVs under a non-disclosure agreement as a preview of the future Windows 3.0 product—which turned into a runaway success and made Microsoft king of the software industry. It was first demonstrated at the annual Microsoft Systems Software Forum in February 1989. Continue reading →

Posted in 386, Microsoft, PC history, Windows | 90 Comments

mtswslnk

Posted on January 14, 2015 by Michal Necasek

Certain older Microsoft software (including Windows font files) contains mysterious strings starting with “mtswslnk”, sometimes longer and sometimes shorter. This led some people to wild speculation about the meaning and purpose of the string.

Let’s start with the full string: it’s “mtswslnkmcjklsdlsbdmMICROSOFT”, although it rarely appears in its entirety. Now there are two questions—what is the purpose of the string, and what does it mean?

Answering the first question is easy. When viewing a binary in a hex editor, it is blindingly obvious that the string can start at any offset, but always ends on a 16-byte boundary. It almost exclusively (see below) appears in 16-bit segmented New Executable (NE) binaries, and that includes font files. Comparing the string locations with the output of any NE parser, it is apparent that it always occurs at the end of a “section” of an NE image. In other words, it is padding, perhaps used to avoid the problems caused by leaking uninitialized data.

Where does it come from? Well, there’s just one executable where the string appears in full and not aligned, and that’s not an NE image: the Windows Resource Compiler (RC.EXE). The string appears to be located at the beginning of a 512-byte buffer padded with zeros, and itself not aligned in the file. Continue reading →

Posted in Development, Microsoft, PC history | 2 Comments

OS/2 Technical Library Scans

Posted on January 10, 2015 by Michal Necasek

After a lot of scanning and OCRing, here’s the OS/2 2.0 Technical Library (well, most of it) in PDF form. This was IBM’s complete programming documentation for OS/2 2.0, covering general programming, GUI development, Workplace Shell, and device drivers. Certainly an important museum exhibit, and lots of pounds of good quality paper.

It’s interesting to consider what was and wasn’t in there—32-bit pre-emptive multitasking and multithreading, a GUI with advanced graphics engine, DOS virtualization, but strange partially 16-bit device drivers and no built-in networking.

Note that bitsavers has a subset of the Warp 3 version of the Technical Library, but it’s only the Presentation Manager documentation, at least currently. Most of the documentation also existed in electronic form.

Posted in Documentation, OS/2 | 8 Comments

Book Review: Inside Windows NT

Posted on January 3, 2015 by Michal Necasek

A Few Decades Late Book Reviews

Inside Windows NT, by Helen Custer
Microsoft Press, 1992; 385 pages, ISBN 1-55615-481-X; $24.95

Inside Windows NT was one of the earliest published books about Windows NT, predating the actual July 1993 release of Windows NT 3.1 by several months. Helen Custer joined Microsoft as part of Dave Cutler’s team of ex-DEC engineers; her task was to chronicle the development of NT and describe the new operating system in a way accessible to “the rest of us” (who care about operating systems). Continue reading →

Posted in Books, NT | 6 Comments

Ladders and Dragons

Posted on December 28, 2014 by Michal Necasek

While looking at the Windows 95 disk subsystem, something seemed oddly familiar. The nagging feeling was confirmed by the Windows 95 DDK documentation (a file called BLOCK.DOC). The new Windows 95 layered block device driver model called “Dragon” wasn’t all that new—it was a modified implementation of Microsoft’s older LADDR (pronounced “ladder”), or Layered Adapter Device DRiver model which first appeared in MS OS/2 in 1990. The LADDR subsystem could be retrofitted to OS/2 1.2 (producing “LADDRized OS/2”) and came standard with MS OS/2 1.3 (i.e. LAN Manager 2.1).

The structure of LADDR and Dragon was obviously quite similar, although there were just as importantly significant differences. The fact that LADDR was 16-bit and Dragon 32-bit was not necessarily a great difference. But for instance SCSI adapter support was noticeably different. Windows 95 could use NT miniport drivers (.MPD), which weren’t at all relevant with LADDR. Dragon also included special support for real-mode DOS drivers, which was likewise a non-issue with OS/2. Continue reading →

Posted in OS/2, PC history, SCSI, Windows 95 | Leave a comment

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, RSLDT, SVTS, RSTS, SMINT, XBTS, IBTS, ZALLOC.

Mr. Chappell then explains why Intel never mentioned SVDC, RSDC, SVLDT, RSLDT, SVTS, RSTS and SMINT: Those are instructions defined by Cyrix and in fact reasonably well documented.

But that still leaves seven instructions: LOADALL, CFLSH, WRECR, RDECR, XBTS, IBTS, and ZALLOC. What are those instructions? And why did Intel not document them?

Continue reading →

Posted in Documentation, Intel, x86 | 11 Comments

Windows 8.1 Startup Bugcheck 0xC4

Posted on November 30, 2014 by Michal Necasek

On some systems, both physical and virtual, 64-bit Windows 8.1 as well as Server 2012 R2 consistently crashes with error code (bug check) 0xC4; 64-bit Windows 8 may run on these same systems without trouble. On physical systems, the BSOD is typically accompanied by the machine rebooting so fast that it is very difficult to read the error message at all. If the system keeps attempting to boot Windows 8.1, this results in a nice reboot loop.

In VirtualBox, users at least have a chance to read the error message before the VM terminates with a fatal error:

Not that the error message is in any way helpful. According to MSDN, bug check 0xc4 means DRIVER_VERIFIER_DETECTED_VIOLATION and the first argument of 0x91 is “reserved”. But wait, a driver verifier violation usually means buggy software, so how can that happen with a Windows 8.1 installation DVD? Windows 8.1 couldn’t be buggy, could it? Continue reading →

Posted in Bugs, Microsoft, NT, VirtualBox | 15 Comments

ThinkPad 850 Hardware Maintenance Manual

Posted on November 14, 2014 by Michal Necasek

Thanks to a very helpful reader (Mike Senior—thanks!), the OS/2 Museum can now publish the ThinkPad Power Series 850 Hardware Maintenance Service and Reference manual in the form of a PDF. This is IBM document number 30H2383. The manual might be of help to owners of antique PowerPC portables. The PDF isn’t perfect but it should be quite useful.

Anyone who needed to take apart a ThinkPad knows that although the process isn’t necessarily terribly difficult, it is complicated enough that dismantling a ThinkPad without the corresponding HMM is a perilous journey. And no one wants to break a PowerPC ThinkPad.

There’s very little else to say, just that although the HMMs for Intel-based ThinkPads have long been available in electronic format (for all ThinkPads, even ones much older than the 850), the ThinkPad 850 HMM was for some reason never available electronically, and the HMM is nowadays even harder to find than the actual ThinkPads.

Posted in Documentation, PowerPC, ThinkPad | 5 Comments