The latest episode from Commodore History takes a deep dive into the often-overlooked Commodore 1570 disk drive. By cracking open its case and comparing it to the better-known 1541 and 1571 models, this episode explores the drive’s construction, performance, and quirks when connected to real hardware.
The Commodore 1570, a 5¼-inch floppy disk drive, was specifically designed for the Commodore 128. Unlike its double-sided successor, the 1571, this drive was only single-sided, offering 170 kB of storage. It was born out of necessity—Commodore International faced supply shortages of double-sided drive mechanisms, forcing them to create a temporary alternative. Despite its interim status, the 1570 had some impressive capabilities. It could read and write both GCR (Group Code Recording) and MFM (Modified Frequency Modulation) disk formats, making it more versatile than the older 1541.
While the 1570 inherited a 1571 logic board, it came encased in a shell resembling the original cream-colored 1541. It also featured a drive mechanism similar to the 1541 but with a key upgrade—track-zero detection. Additionally, its built-in DOS supported a data burst mode, enabling faster data transfers when paired with a Commodore 128. This advantage, however, was lost on Commodore 64 users, as the C64 could not utilize this enhanced speed. To those using the 1570 with a C64, it was little more than a pricier version of the 1541.
Interestingly, many early C128 adopters initially stuck with their old 1541 drives, waiting for the full-featured 1571 to become widely available. However, for those who did use the 1570, they benefited from several DOS bug fixes that wouldn’t appear in the 1571 until later revisions. The drive also had full compatibility with all single-sided CP/M-format disks that the 1571 could read and write.
Under the hood, the Commodore 1570 was powered by a MOS 6502 CPU, supported by a WD1770 or WD1772 floppy controller, and I/O controllers that included two MOS Technology 6522 chips and a single MOS Technology 6526 chip. These components worked together to ensure smooth operation and compatibility with Commodore’s 8-bit ecosystem.
Though it was never intended as a long-term solution, the 1570 carved out a small but significant place in Commodore’s history. Its blend of 1541-style hardware with 1571 software enhancements made it a fascinating bridge between old and new technology. For C128 users who couldn’t get their hands on a 1571 right away, the 1570 was a capable alternative, albeit one with limitations.
