Micro Systems Development
| Company type | Private |
|---|---|
| Industry | Computer hardware |
| Founded | 1983 |
| Headquarters | Dallas , United States |
| Products | MSD Super Disk floppy disk drives (SD-1, SD-2) |
The MSD Super Disk lineup consisted of 5¼-inch floppy disk drives developed by Micro Systems Development (based in Dallas, Texas, later known as MSD Systems) specifically for Commodore's 8-bit home computers. This series included two versions: the single-drive SD-1 and the dual-drive SD-2, both offering partial compatibility with the Commodore 1541 disk drive.
Introduction
Introduced in 1983, the MSD Super Disk drives represented the earliest third-party hardware compatible with the Commodore 64. Equipped with both an IEEE-488 parallel interface and Commodore’s proprietary serial interface, these drives connected directly to any Commodore 8-bit machine—from the PET through to the C64 and C128—without requiring additional adapters.
Features and pricing
The SD-1 model carried a higher price tag than the Commodore 1541; for instance, a mail-order advertisement from January 1985 listed the SD-1 at $249.95 compared to $199.95 for the 1541. The dual-drive SD-2 was offered at $449.95, which was considerably more affordable than the dual-drive CBM 4040 priced at $699. To justify its premium cost—generally around $50 above the 1541—MSD highlighted enhanced build quality and superior performance characteristics.
A 1985 evaluation published in RUN Magazine commended the SD-2 for its sturdy construction and dependable operation during extended use. Although data transfer speeds over the serial interface matched those of the 1541 due to technical constraints, both models delivered substantially faster throughput when utilizing the IEEE-488 connection. MSD also provided VIE and CIE IEEE-488 interfaces tailored for VIC-20 and C64 systems. Formatting a blank disk on an MSD drive took approximately 18 seconds, markedly quicker than the over one minute required by the 1541.
The SD-2 supports Commodore DOS's Duplicate command inherited from earlier PET dual drives, featuring two synchronized mechanisms and 6 kB of RAM that enable full-disk duplication in less than two minutes. While it cannot efficiently read or write an entire track (~7 kB) per disk rotation, an expansion module allows additional RAM installation. Third-party enhancements such as Chip Level Designs’ Mass Duplicator significantly reduced duplication time to around 22 seconds per disk.
Commodore BASIC V4.0’s COPY command functions with the SD-2 for transferring files between drives—a capability not available when using two separate 1541 units. However, due to differences in DOS programming and hardware design, MSD Super Disk drives exhibit compatibility issues with many copy-protected titles.
Both models incorporate TEC brand (model FB-501) floppy mechanisms that MSD modified to support Commodore’s GCR recording format, which was standard across their floppy drives at that period (distinct from MFM formats used in hard disks and later drives). The primary control board is powered by a Rockwell International 6511Q microcontroller operating at 1 MHz.
Reception
Ahoy! magazine recognized that while the SD-2 was incompatible with certain software designed for the 1541, it concluded that "dedicated Commodore 64 users will find the $695 investment well justified. The time saved when backing up disk files quickly compensates for the cost," further describing it as a compelling alternative to the CBM 4040.