Mon, 03 Oct 1994

IBM goes OEM with its Cobalt AT 486BL motherboard

By Zatni Arbi

JAKARTA (JP): All right! Finally, I've happily gotten rid of my old albeit faithful 386 PC. Well, partly. I still have most of its components, including the case, the two floppy disk drives, the Orchid Fahrenheit 1280 graphics accelerator card, the Northgate Omnikey keyboard and one of the two 240 MB Quantum ProDrive hard disks. All I did was replace the motherboard and add to the new one a single 16 MB SIMM RAM as well as a new 540 MB ProDrive.

As for the motherboard, I guess I was lucky to be able to obtain one made by IBM. That's news, isn't it? We all know about IBM Value Points and ThinkPads, but not many of us were aware that this computer giant has also been selling motherboards and subsystems in addition to complete systems and CPUs.

Now, with its notorious tendency to use uncommon computer jargon, IBM calls its Cobalt AT 486BL a system board instead of a motherboard (for that matter, IBM also calls a hard disk a 'fixed disk'). Nevertheless, at a price below Rp 1 million for the motherboard that comes complete with the CPU, a 80387DX math co- processor, 256 KB cache, and other goodies that I'll describe subsequently, you might be surprised to hear that it is a bargain as well as a masterpiece.

Blue Lightning

The Cobalt AT 486BL System Board that I bought was equipped with an IBM version of clock-tripled 486 CPU called Blue Lightning. It came with a heat sink. Again, not wanting to use the more commonly known jargon, IBM calls the chip a "triple clocked" CPU instead of the more commonly used "clock-tripled" (this is for you linguists out there to figure out). Anyway, I wrote about this clock-tripled generation of CPUs some months ago. In fact, IBM beat Intel in releasing clock-tripled 486 chips in the market. You might also recall that Intel's version of the clock-tripled 80486s is called DX4.

Internally, IBM Blue Lightning (BL) CPU on this motherboard runs at the speed of 75 MHz, while externally it communicates with the other components at 25 MHz. That gives me a Norton Desktop's benchmark reading of 144.3 relative to the speed of an XT and PCTools reading of 74.7. Landmark 2.0 reading is reported ly 172.74. That should be sufficient for me -- for the time being.

One thing that distinguishes Intel's DX4 from IBM BL is that the latter does not have a built-in math co-processor. I did not have to worry, however, since Cobalt AT 486BL System Board al ready came with a Cyrix FasMath co-processor.

Accompanied by the co-processor, IBM positioned the 25/75 MHz BL CPU against Intel 486DX2 66. In case you're wondering what kind of relationship this computer maker has with the chip maker, here's the story: IBM and Cyrix have a five-year agreement that makes the former the primary manufacturer of Cyrix X486 processors. This gives IBM access to 486 technologies.

Should the time come and I no longer find 75 MHz sufficient to satisfy the next generation application software's hunger for speed, it seems that I'll still be in a good shape since the board can accept a Pentium OverDrive chip when it becomes avail able. Like most other upgradeable motherboards, a zero-insertion- force, or ZIF, socket is available.

VL-bus IDE

The motherboard has seven 16-bit ISA slots and two VL-bus slots with bus mastering capability. However, I now have more free slots than I did on the old, eight-slot 386 motherboard. Two cards are now no longer necessary: The hard disk controller card and the I/O card. This motherboard has an embedded IDE controller that uses the VL-bus specifications. It uses the Appian ADI2 Fast IDE Interface chip from Appian Technology.

Activating the VL-bus IDE controller required that I install Appian Disk Accelerator Device Drivers, which was included in the package. There was a driver for DOS, and there was another for Windows. The latter automatically turned on the 32-bit Disk Access of Windows for Workgroups, which makes hard disk operation even speedier.

At first I forgot to install the drivers and the system worked as slowly as my old 386. When I turned on the WFWG 32-bit Disk Access without installing the drivers, the system even crashed. Only after both drivers had been installed properly did I see the real performance, and I really said "Wow!". I had some problem installing Microsoft Office 4.2, though; I had to disable the 32- bit Disk Access before I could install the entire Office package. Once installed, I could turn on the 32-bit Disk Access again and everything became fast once again.

The MR BIOS setup also has an option of 32-bit block transfer mode, and that further increases the speed of the hard disk access.

Built-in Anti-virus

On my old boot hard disk there was an unknown virus that stayed there because I was unable to clean it. Luckily, MR BIOS has its anti-virus protection for hard disk C:. I really love this, as viruses are really getting out of hand nowadays -- unless you keep spending your money on new updates of anti-virus software. The option write protects the main boot sector of hard disk C:

Combined with BOOTSAFE from PCTools and NAVTSR from Norton, this protection is perhaps more than enough to guard against viruses. However, like many other things in life, too much pro tection can be hazardous as well. I spent 40 minutes helplessly working with Rescue Disk and SYSTEM.INI after I accessed the CMOS setup utility just to read its current settings.

Here's what had happened: When I exited the CMOS utility, NAVTSRW detected that the CMOS was changed and it stopped Windows cold during boot time. When I tried to restore the CMOS settings from the Norton's Rescue Disk, the system BIOS halted the system as it detected some external program was trying to rewrite the boot and partition table of the hard disk. I shouldn't have exited the utility, I should have just pressed the Reset button. Now I had to re-install NDW.

All aboard!

Perhaps one of the features that I liked best was the embedded controllers. This motherboard comes with an on-board Super I/O that supports two fast serial ports (ehm, IBM calls them 'Asy nchronous' ports), one bi-directional parallel port with EPP and ECP supports. This makes the I/O card no longer necessary.

The board also contains an integrated floppy disk drive controller that supports two drives, and you can attach one or two 2.88 MB capacity drives to it.

The package comes with all necessary ribbon cables (see the accompanying illustration). Increasing RAM capacity could not be easier; all you have to do is plug in the SIMMs and there's no jumper or switch that you should tinker with.

All BL CPU chips have a built-in 16 KB internal cache. The board comes standard with 256 KB of external cache. This is the minimum of what you should have in a fast 486 system today. If this amount of external cache turns out to be inadequate for your applications, you can increase it to 512 KB. But that would be a fairly expensive upgrade, as it will require 20 ns static RAM chips.

Easy installation

Installing the board to my full-tower chassis posed no difficulty at all. Attaching all the internal cables -- such as the speaker and reset cables -- was easy, too, as everything was clearly marked. However, when I switched on the PC for the first time, I got only a series of beeps and nothing else happened.

It turned out that I was using the wrong type of SIMM. I was using two 8 MB Kingston SIMM. When a 16 MB SIMM was plugged into SM1, the first slot, everything worked well. This motherboard supports up to 64 MB of RAM in total with its four 72-pin SIMM sockets.

The setup utility of MR BIOS also allows us to specify the boot sequence. It even has the Auto-search option, making it possible for us to boot from Drive B:. That's another new thing about this motherboard. Like many other late model boards, we can also use the Auto-detect utility to find out the correct CMOS setting for our hard disk, in case it is not a common type or we don't have the correct parameter settings for it at hand.

Unfortunately, IBM Microelectronics -- the division that makes this motherboard -- came short of providing us thorough documentation for this product. There's no troubleshooting section, so it took me a lot of guessing before I was able to figure out the wrong type of SIMM. There was no mention of the anti-virus option, either. The information in the manual is very minimal. In the CMOS setting there is an option "Daylight Saving" that we can enable or disable; in the manual there's no explanation of what it does. The Introduction does warn readers that the manual is intended to provide general guidelines only.

Final word

The Cobalt AT 486BL System Board is targeted at the lower mid- range computer market, namely for PCs costing less than US$ 2,000.00. More expensive boards from IBM Microelectronics have integrated VL-bus video graphics controllers as well. Of course, it would be nice to have SCSI-2 on board as well. For now, if you're looking for a high-quality and yet reasonably priced replacement for your 286 or 386 motherboards, this one is highly recommended. Backed with IBM's three-year warranty, this should be a sound investment.