While the OS/2 Museum employs modern computers and virtualization heavily, sometimes there is a need for good old hardware—emphasis on good and old. A virtual machine won’t read 5¼” floppies and there’s no way to plug in a real Sound Blaster AWE32 or an Adaptec 1540CF.
There is a definite need for an old system, yet at the same time the system should not be too slow and too limited. Indeed there are conflicting requirements: The system should be fast, have lots of RAM, a big disk, yet needs to support ISA slots and 5¼” floppy drives. An AGP slot is a must. The system should also be maximally stable and compatible. If at all possible, the system should support SMP (likely a dual-processor system).
The stability and compatibility requirement favors an Intel CPU and an Intel chipset. The objective is not the best bang for the buck (any hardware that old is likely to be cheap, if not free), the objective is a system that works.
If Intel chipsets (and CPUs) are taken as a constraint, the chipset choice is surprisingly limited. A brief look at the list of Intel chipsets reveals that there are rather few candidates; the 810/820/815 chipsets removed ISA support, which leaves the older 440/450 generation. The 440MX is mobile only, 440ZX is just slightly crippled 440BX (no SMP support, fewer memory slots). The 450NX is a server chipset which supports up to 8GB RAM(!) but does not support AGP and cannot use SDRAM. That leaves 440BX and 440GX. The latter was used mostly in server-oriented motherboards and there are extremely few suitable candidates.
The 440BX (Seattle), on the other hand, was one of Intel’s most popular chipsets ever, perhaps slightly better than Intel intended—and preferred by many to its designated successors (the 810 and 820 chipsets). It was a high-end yet not particularly expensive desktop chipset; indeed some even say that “something went horribly right at Intel when the 440BX chipset was designed”. The motherboard choice is extremely broad, with both single- and dual-processor boards.
The 440BX supports up to two processors, 1GB RAM, Ultra DMA/33, EDO or SDRAM DIMMs, AGP 2x, and 66 or 100MHz FSB (with CPU and memory running at the same FSB frequency).
The choice of processor is trickier. The 440BX/440GX chipsets support Pentium II, Celeron, and Pentium III CPUs with FSB speeds up to 100 MHz, but do not support the faster Pentium III processors (at least not officially or not without some sort of hardware hackery). Then again, a 400-600 MHz processor should be just fine for the purpose.
The processor choice is tied to the motherboard’s slot or socket type. 440BX-based motherboards supported Slot 1 or Socket 370, either in single or dual configurations. Pentium II processors and early Pentium IIIs (Katmai) were all designed for Slot 1, while most Celerons and later Pentium IIIs (Coppermine and Tualatin) used the Socket 370 form factor.
440BX Slot 1 motherboards don’t support the newer Pentium III models, and neither do the older Socket 370 boards; the problem is lower voltage (which requires hardware shims) as well as BIOS support (sufficiently uptodate BIOS required).
Then again… perhaps the CPU speed doesn’t matter that much. After all, the machine isn’t supposed to run Windows 8—it needs to run OS/2, DOS, Windows 2000 or Windows XP, perhaps Windows 98, probably Linux.
The Default Choice: ABIT BP6
It just so happens that I’ve owned one of the famous ABIT BP6 boards since 1999. It was my main system for a while, relatively soon replaced by a 600 MHz Pentium III with the 440ZX chipset.
The BP6 is best known as the first board which supported SMP configurations with Mendocino Celeron PPGA processors, something that was not possible according to Intel. Those Celerons were a little like the 440BX chipset—perhaps a little better than Intel intended. Based on the Pentium II core, the Mendocino Celerons had only 128KB L2 cache (vs. 512KB on the “real” Pentium IIs), but running at full CPU speed rather than half-speed as the Pentium II’s L2 cache did. As a result, the Mendocino Celerons had an interesting profile, being either faster or slower than a Pentium II at the same frequency, depending on whether the task at hand benefited from the larger cache or not (the majority did).
After years of neglect, the BP6 was resurrected and reinstated into OS/2 Museum service. It is currently equipped with two 533 MHz Mendocino Celeron CPUs, the fastest the board supports without any hacks or overclocking. Memory has been upgraded to 640MB (the maximum is 768MB, with 3 slots).
The BP6 fulfils most of the requirements: it sports two ISA slots, an AGP 2x slot, and five PCI slots. It has the usual PS/2 mouse and keyboard connectors, two serial and one parallel port. Best of all, it includes the Intel 82093AA I/O APIC and runs SMP operating systems (OS/2, Windows XP, Linux) very well.
The BIOS (AWARD 4.50) implements proper 5¼” floppy drive support, which is something more recent BIOSes often lack.
The system is very stable and quite a decent performer. It’s equipped with a 120GB Western Digital disk and a Radeon 9200 AGP graphics card. The graphics card was chosen as one of the very few AGP models available around 2010 with both a DVI and a VGA connector.
It’s not all roses of course. The biggest drawback of the BP6 is that it doesn’t natively support anything faster than those 533 MHz Mendocino Celerons. It is possible to install newer CPUs with various adapters, but usually at the cost of a loss of SMP functionality. That’s not worthwhile.
Since the 440BX chipset only supports Ultra DMA/33, the BP6 designers thought it’d be nice to put a HighPoint Ultra DMA/66 IDE controller on the motherboard. Sadly, the controller isn’t supported in Windows 2000 and later, which makes it useless (and the Ultra DMA/33 performance is quite sufficient anyway). The standard BIOS does not have an option to disable the HighPoint controller, just to increase the annoyance.
A minor issue is that the BIOS can’t support IDE disks larger than 128GB. For this system, the current 120GB disk is more than big enough.
Can We Do Better?
Is there a better board out there? Probably. But to make an upgrade worthwhile, the replacement would have to support two Pentium III CPUs at 700+ MHz (with 100MHz FSB). That does not leave a lot of candidates. Perhaps a Tyan Tiger 100? An EPOX KP6-BS? A Soyo SY-D6IBA? A Gigabyte GA-6BXD? A DFI P2XBL/D? An Iwill DBD100? With most of these boards, it is quite difficult to determine the fastest supported CPU model.
There are various server-oriented boards (some built around the 440GX), but most of those aren’t too attractive. Integrated SCSI controllers or graphics cards are more of a drawback as the OS/2 Museum already has a decent collection of SCSI adapters and graphics cards, many of them better than what’s integrated on those boards. Many have just a single ISA slot, which is again a minus. 2GB RAM capacity isn’t that much of a big deal (compared to 1GB which the desktop board support).
Any suggestions, dear readers? Is there a vintage board which is in all respects at least as good or better than the BP6?
After some research, it looks like Slot 1 is indeed the way to go. Should the need arise, there are “slockets” for installing PPGA processors in Slot 1 boards, whereas no such device exists for the opposite direction. Slot 2 (Xeon) seems too exotic with questionable performance benefits (as those Xeons didn’t seem to be available in speeds over 700 MHz or so). It should be possible to install dual 1 GHz Pentium IIIs (Coppermine with 100 MHz FSB) in the right boards.
The top candidates currently are ASUS P2B-D (Rev. 1.06) and Tyan Tiger 100 (Rev. F). Both are reasonably easy to find, though it is often tricky to determine whether it’s the right revision with Coppermine CPU support. The Supermicro P6DBE and Gigabyte GA-6BXD also sound promising. All of these should be superior to the BP6 with the appropriate CPUs.
Curiously, the ASUS P2B-DS with on-board SCSI appears to be the easiest to find. I’d prefer the SCSI-less variant since a) I have a spare Adaptec 29160N anyway, and b) I often need to plug in a different SCSI HBA for testing. That said, SCSI would be the obvious way to work around the 128GB IDE limitation typical for these systems, should 120GB prove insufficient.