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A quick look back at Microsoft's IBM PC add-on cards of the 1980s

Microsoft RAM card ad

A couple of months ago, I wrote an article about Microsoft's nearly forgotten first hardware product, the SoftCard add-on board for the Apple II. It first launched way back in April 1980. The card turned out to be a highly successful one for the company. When the IBM PC game along in August 1981, it included a version of Microsoft BASIC. So it was a natural decision for the company to see if it could duplicate its success with the Apple II SoftCard with something made for the IBM PC.

In 1982, Microsoft released the RAM Card for the IBM PC. According to PC Magazine, it could not only let users expand the available RAM on IBM's personal computer from 64K all the way to 256K, but it could also let users access its RAMDrive. With this feature, you could set up part of the onboard RAM to act as if it was a storage disk for faster access to data. Basically, it's what SSDs are like today.

Unfortunately, searching for an actual image of this board on the internet did not pan out, although I will update this post if there is one to be found.

Microsoft systemcard

In 1983, Microsoft went even further with the launch of the SystemCard for IBM PCs. You could still use it to expand a PC's memory to 256Kb. However, it could also do a lot of other things as well. When you inserted the ISA-based card into an IBM PC, it also served as a printer interface and spooler. The card even had its own calendar and clock chip.

In 1984, Microsoft launched a similar RAM booster card for the new IBM PCjr computer, called the PCJr Booster. Microsoft even included one of its early mouse products with this card. Again, I was unable to find an image of this card online.

In 1985, Microsoft released version 1.0 of Windows, which would eventually become its signature product. However, the bad news was that many IBM PCs simply were not fast enough to run the OS well. They had Intel's 8088 CPU inside but running at a 4.77-MHz clock speed. In 1986, Microsoft released the Mach 10, a motherboard add-on for the IBM PC and some IBM clone PCs. It had a version of the Intel 8086 CPU that had a much faster 9.54MHz clock speed. It even included a port for a mouse.

Microsoft mach 20

However, according to a blog post from Microsoft Senior Software Engineer Raymond Chen, the Mach 10 board was "a flop". Microsoft tried again with the Mach 20 board. Chen stated:

The Mach 20 took the same basic idea as the Mach 10, but to the next level: As before, you unplugged your old 4.77 MHz 8088 CPU and replaced it with an adapter that led via ribbon cable to the Mach 20 card, which you plugged into an expansion slot. This time, the Mach 20 had an 8 MHz 80286 CPU, so you were really cooking with gas now. And, like the Mach 10, it had a mouse port built in.

The Microsoft Mach 20 also daughterboards which could be used to expand the memory of a PC to as much as 3.5MB. Both the processor and the increase in memory allowed PCs with this board to run Windows 2.0 in standard mode. It also allowed the PC to connect to a 5.25-inch or a 3.5 floppy drive.

The Mach 20 went on sale in 1988 for $495, but according to Chen "it sold better than the Mach 10, but then again, that’s not saying much." Indeed, the Mach 20 would be the final PC add-on card Microsoft would sell as it switched over to other hardware accessories like keyboards, mice, and joysticks, among other things.

One interesting side note from Chen's blog is that Microsoft actually created a custom version of IBM's own O/S 2 to run on the Mach 20. However, running this version of the OS still caused so many performance problems that Chen claims that, according to an unnamed former employee, it might be the least-selling software product ever in Microsoft history:

According to that person’s memory (which given the amount time that has elapsed, means that we should basically be saying “according to legend” at this point), a total of eleven copies of “OS/2 for Mach 20” were ever sold, and eight of them were returned.

The PC add-on era at Microsoft has, of course, been over for decades, but it's still fascinating to look back at this particular early era of the personal computer industry.

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