MSD Super Disk

The MSD Super Disk was a series of floppy disk drives produced by Micro Systems Development for use with Commodore 8-bit home computers. Two different versions of the MSD Super Disk were available: the single-drive SD-1 and the dual-drive SD-2.

Introduction

The MSD Super Disk drives were the first third-party devices designed for compatibility with the Commodore 64, although other manufacturers soon followed suit. The MSD drives included both an IEEE-488 parallel interface and the custom Commodore serial interface. Therefore, they could be connected to any Commodore 8-bit system, from the Commodore PET to the C64 and C128, without any converters or add-on devices.

Features and pricing

The MSD drives were more expensive than their Commodore counterparts. For instance, a typical mail-order advertisement in the January 1985 issue of "RUN" Magazine (p. 91) lists the MSD SD-1 single drive at $249.95, compared to $199.95 for the Commodore 1541. (The dual SD-2 was listed at $449.95.) However, they did offer several advantages to justify the higher price. In an August 1985 review of 1541 replacements, "RUN" Magazine wrote that the MSD SD-2 was "built like a tank and can run 24 hours a day for weeks" (p. 28). While program loading and saving was no faster than on a 1541 drive (since the same firmware and serial interface was used), a disk could be formatted in only 18 seconds on the MSD Super Disk series, compared to 1 minute and 22 seconds on the 1541 (p. 26). Also, the MSD SD-2 incorporated the Commodore DOS Duplicate command from the old Commodore PET dual drive series, which allowed it to copy an entire disk in under 2 minutes. The DOS Copy command could also be used to copy files from one drive to another on the MSD SD-2, a feature not available with two 1541 single drives. However, the MSD Super Disk drives had difficulty loading most copy-protected software, due to substantial differences in the DOS code and memory mapping.

References

* [http://staff.washington.edu/rrcc/uwweb/MSD-SD2/ MSD SD-2 operating manual and schematics]
* [http://www.devili.iki.fi/Computers/Commodore/articles/Enhancing_Your_64/ The Peripheral Connection: Enhancing Your 64]