Still on the theme of unusual hardware… in my junk pile there’s one of these rather special little parts:
As the label on the PCB says, this is a 486 pod for a Periscope IV debugger. The Periscope Company of Atlanta, GA was a respected supplier of hardware-assisted debuggers in the late 1980s and early 1990s. Continue reading
Since some of this blog’s readers are very good at recognizing obscure hardware, I thought I’d post photos of one more somewhat exotic graphics card:
This board was one of the early PCI graphics adapters. It’s old enough that it doesn’t use the standardized PCI class ID. It’s based on the S3 928P chip and equipped with 1MB video memory. Continue reading
Since some readers appear to enjoy identifying prehistoric graphics cards, I thought I’d post photos of two more TIGA boards from my junk pile. I know what these are, but do you? One of them ought to be fairly easy to identify and photos of it exist on the Internet. The other one might be tougher and to my knowledge no photos of it are available.
Let’s start with Exhibit A: This is an ISA-based graphics card by a well known manufacturer whose name is clearly legible on the PCB. It’s a combined VGA + TIGA card, a somewhat unusual yet very logical combination.
There’s a 60MHz TMS34010 GPU and a BrookTree Bt473 DAC. The DAC is a 66MHz part, so no fancy high-res modes, just basic 1024×768. Somewhat unusually, the board uses standard 30-pin SIMM slots for GPU memory, which means it was probably user upgradable. There is separate VRAM in typical ZIP modules. Continue reading
My junk pile turned out to contain another board by Vermont Microsystems, Inc. (VMI), probably no less exotic than the mystery board.
This one is a Microchannel board built around an Intel 82786. An in this case, VMI was kind enough to etch their name on the PCB, complete with the model name—Page Manager 100. Continue reading
While cataloging my junk pile, I came across two graphics cards that I could not identify. Both are high-end ISA graphics accelerators from the early 1990s and both utilize Texas Instruments GPUs (long before the term “GPU” was first used, but very appropriate).
The first card was clearly made by SPEA (that is, SPEA Software AG), a German company known for its high-end graphics card. Based on the chip markings, the card must have been manufactured in the second half of 1991.
The site has been unavailable for a while because some creative person or persons decided to use it for sending out spam and setting up a beautifully crafted facsimile of PayPal. It appears that a vulnerability in an old WordPress version was exploited some time ago (several months ago at least); for a while, nothing more happened, but on Dec 31st the attacker(s) started uploading foreign content to the site.
Part of the problem is that WordPress updates do not delete old unused files. In this case, the old and no longer used ‘default’ theme was somehow modified and then used as a backdoor. Because WordPress updates neither delete the unused scripts nor overwrite them, malicious PHP scripts hung around for at least a few months. Learn something new every day…
Let’s hope the problem is now resolved and the site will stay up for a while.
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 sector contain a jump instruction, which then presumably skips over the BPB. The MSDISK.INC module in the MS-DOS 3.21 OAK is a good example. The opcodes considered valid are EBh (JMP short), E9h (JMP), or 69h. Wait, an IMUL instruction? Well, no, that’s not what the comment in the source code says:
cmp byte ptr cs:[DiskSector],069H ; Is it a direct jump? je Check_Signature ; don't need to find a NOP cmp byte ptr cs:[DiskSector],0E9H ; DOS 2.0 jump? je Check_Signature ; no need for NOP cmp byte ptr cs:[DiskSector],0EBH ; How about a short jump. jne BadDisk
The problem is that 69h is not a documented 8086 instruction. It’s an IMUL opcode on 80186 and later, but that seems highly implausible. Besides, the comment clearly says it’s a jump.
Since the undocumented 8086 opcodes are, well, undocumented, could 69h possibly behave like a jump on an 8088/8086 processor? A very good question, with remarkably few answers. One might think that in the hacker culture surrounding early PCs, it would be inevitable that someone would find out what the undocumented instructions really do. But that doesn’t appear to be the case. A fairly exhaustive search turned up nothing, even in books like Undocumented PC (Frank van Gilluwe) which devote significant space to undocumented instructions. It still seems that someone, somewhere must have published something…
A quick look at several emulators turned up nothing either. Fortunately, Raúl Gutiérrez Sanz had a genuine 8088 and enough determination to find out what the undocumented opcodes really do. Continue reading
With VirtualBox 4.3, it is possible to install the oldest known pre-release of Windows NT directly from CD, the way Microsoft intended. This is the Fall ’91 Comdex preview which only supported the x86 architecture and a very short list of hardware devices. The pre-release was available only on CD-ROM and although it was possible to install it more or less manually from DOS, there was a graphical installer on the CD-ROM.
However, the hardware support being as limited as it was, the only supported storage controller was Adaptec AHA-1540 or compatible with a SCSI CD-ROM attached. Fortunately this is adequately emulated by the BusLogic SCSI HBA device in VirtualBox.
I recently tried to revive an old ThinkPad 600 (with a 300 MHz mobile Pentium II processor). The system wouldn’t boot up and reported errors (173, 163) which are usually a good indication of a dead CMOS battery. In a 15-year old system, that’s not particularly surprising.
So I opened the memory cover on the bottom of the laptop, removed the CMOS battery from its housing, and pulled on the cable… only to break off the connector from the board instead of just unplugging the wires.
Unfortunately the CMOS battery connector is located right under the shell and can’t be re-attached without more or less completely dismantling the entire laptop, which I proceeded to do. Continue reading
Ars Technica today published an article titled “Half an operating system: The triumph and tragedy of OS/2“. Although very interesting, unfortunately the article to a significant extent engages in what can best be called fantasy history, which causes the text to contradict itself. And while it attempts to present a coherent view of the history of OS/2, the article is more a hodgepodge of facts/products/trends (PS/2, NT, PowerPC) picked at random to support an argument.
It also presents the old “geniuses at Microsoft vs. dumb IBM” story which is increasingly difficult to justify as time marches on. IBM is the bad guy, overly bureaucratic and incompetent. Yet listening to old IBMers a somewhat different picture emerges, with Microsoft being a disorganized, sloppy company producing poorly documented and buggy software. As always, there’s some truth to both sides of the story.
Let’s start with some of the inaccuracies. When OS/2 was conceived and designed, it wasn’t called OS/2 at all. In fact there is no known evidence that the name OS/2 existed before 1987. The name OS/2 had a lot to do with PS/2, but the OS itself not so much. Continue reading
