I saw a YouTube video last week about the MSD Super Disk Drive, and the creator of the video said he couldn’t find any information about the drive. So I figured I would write something about it, since I kind of like Commodore stuff, and MSD was the first company to make third-party Commodore-compatible disk drives. But that’s not the only thing that made the MSD drives special.
Who MSD was
MSD stands for Micro Systems Development, and it was headquartered in Dallas. Some of its key personnel had worked at Commodore, but they split from Commodore in 1982 to start making Commodore compatible peripherals, including disk drives.
The MSD Super Disk drives, also known as the SD-1 and SD-2, were the right product at the right time when they were released. They were compatible with both the Commodore IEC interface and the IEEE-488 interface. This meant the MSD drives worked with the PET / CBM series of computers and also worked with the VIC-20 and Commodore 64. They connect up just like a Commodore drive would, and they use the same commands.
In 1983 when MSD released its drives, Commodore was selling C-64 and VIC-20 stuff nearly as fast as they could make it. The lack of production capacity meant PET/CBM owners might not necessarily be able to buy a Commodore disk drive if they needed one. But they could buy an MSD drive.
It was also a compelling alternative to the Commodore 1541 drive. The 1541 was in short supply, but it also wasn’t exactly beloved. The MSD drives offered a sturdy alternative.
MSD build quality
MSD drives used modified TEC FB-501 floppy drive mechanisms and a cream-colored steel enclosure. Unlike many Commodore drives, MSD oriented the drive mechanism vertically, so even the dual drive SD-2 model took less space on a desk than a 1541. At the time, critics considered them superior to the Alps and Mitsumi mechanisms that Commodore used, although when you find one today, you’ll find it needs capacitors replaced. Replace the caps and fix any damage to the traces they left behind, and they’re still great.
The metal case dissipated heat well, so BBS operators liked the MSD drives as well, for the time period when they could get them.
They were expensive, but there was a reason for that. The additional circuitry to support both bus types increased the cost. Also, the price was relative. At a retail price of $399 for the SD-1 and $699 for the SD-2, the MSD drives cost more than a 1541, but they cost less than Commodore charged for a comparable PET drive.
What was special about MSD drives
The MSD SD-2 is especially beloved because it is the only drive that can plug into a stock VIC-20/64/128 that acts as a dual drive on a single device number like Commodore’s PET drives. This means its built-in DOS has a function to copy disks and it generally copies more quickly than a pair of 1541 or similar drives would since it doesn’t have to send the data over the IEC bus. An MSD could copy a disk in two minutes, versus 35 minutes for two stock 1541s using standard copy software.
There was a third-party add-on from a company called Chip Level Designs that turned the SD-2 into a standalone disk duplicator, and another that allowed it to duplicate disks in 22 seconds. Third-party products to speed up copying between two 1541s also existed. But none of them could match the modified MSD SD-2 for speed.
For those who didn’t want to modify their drives, some versions of the popular copy program Fast Hack’em included an MSD SD-2 copier that took advantage of the two drives to make copies of disks in about 60 seconds, twice as fast as the drive’s normal speed, and you could unplug the drive from the computer after it loaded and the MSD SD-2 would keep copying disks as you swapped them. Fast Hack’em also included advanced copiers for the MSD SD-2 that could copy disks that the regular copier couldn’t, albeit more slowly.
MSD Compatibility with the Commodore drives
The ironic thing is that the MSD drive was really adept at copying disks that it couldn’t load. Commodore software, especially games, typically had copy protection on them, a 1980s form of DRM. These DRM schemes often relied on idiosyncrasies of the 1541 itself, and they would fail on many third party drives.
The 1541, unlike this drives for many other computers, was a small computer itself. It has its own dedicated 6502 CPU, peripheral chips, RAM, and ROM. Commodore DOS resided in the disk drive itself, not in the computer.
Besides using different drive mechanisms, MSD built its disk drive a little differently than Commodore did inside too. For one thing, instead of a 6502, it used a Rockwell 6511Q microcontroller. This meant that DRM schemes that loaded their own code into a 1541 had trouble with the MSD since it wasn’t the same architecture. The problem was not at all unlike trying to run IBM PC software on a DEC Rainbow or Tandy 2000. Some things worked, but a lot of things didn’t.
The MSD drives’ legacy
Over time, various 1541 clones appeared with better degrees of compatibility, notably the Excelerator Plus. They frequently violated Commodore copyrights in the process, but they cost less and were compatible. So they caused problems for MSD while Commodore played whack-a-mole suing the makers of the third party drives. Around 1986, MSD stopped selling the drives.
Today, the drives are rare and expensive. They never sold in the kind of volumes the 1541 did. And the dual drive version in particular attained legendary status. If you ever attended a Commodore copy party in the 1980s, you almost assuredly saw at least one person with an SX-64 portable and an MSD SD-2 connected to it. Those types of events were exactly the place I encountered them.
David Farquhar is a computer security professional, entrepreneur, and author. He started his career as a part-time computer technician in 1994, worked his way up to system administrator by 1997, and has specialized in vulnerability management since 2013. He invests in real estate on the side and his hobbies include O gauge trains, baseball cards, and retro computers and video games. A University of Missouri graduate, he holds CISSP and Security+ certifications. He lives in St. Louis with his family.