4-minute video on the Cadillac of Commodore 8-bit floppy disk drives: the 1581.
The Commodore 1581 is a 3-and-a-half inch (3.5”) floppy disk drive that debuted in 1987 for Commodore 64 and 128 computers. It was even compatible with the Plus 4, Commodore 16 and VIC-20. Can you imagine using the 1581 with a VIC? It would have been insane!
The 1581 uses double-sided double-density disks formatted in a Modified Frequency Modulation scheme, or MFM, which could also be used with CP/M, IBM compatible PCs and Amigas. These disks can store up to 800 kilobytes of data, 400 per side. The 1581 was the highest capacity serial-bus floppy drive ever produced by Commodore for its 8-bit line, although CMD (Creative Micro Designs) would later surpass it in the early 1990s.
As a comparison, a single side of a Commodore 64 5-and-a-quarter floppy disk could hold approximately 170 kilobytes (so a little over 300 KB per disk if you notch a disk, flip it and use both sides). Therefore, a Commodore 1581 disk can hold more than twice a double-sided 5.25” “flippy disk”, and over 4 times a single-sided 5.25” floppy.
With special software and under the right conditions, it is even possible for the 1581 to read MS-DOS disks. And even cooler, the Amiga can read 1581 disks, too.
The 1581 also supports the C128’s burst commands - commands used for machine language programs - that transfer data several times faster than the standard or fast serial rates. (Sorry Commodore 64s, no bursting for you!). It can automatically adjust its speed to the computer it is connected to, Compared to a 1541, the 1581 has about 20% faster loads and about 45% faster saves. Add JiffyDOS to the mix and it might feel like it is hitting Warp 9.
The 1581 also has support for sub-partitions and directories, which helped make it become an archivist’s dream, not to mention Bulletin Board sysops needing a lot more space at the ready.
However, unlike the 1571, which is nearly 100% backwards-compatible, the 1581 is only compatible with previous Commodore drives at the DOS level. It can’t utilize software that performs low-level disk access, which the majority of C64 games do. To be honest, this major flaw is really the only knock against it. But from a pure storage perspective, the 1581 was, and is, a great piece of period-correct hardware.
At the end of the day, the 1581 is one of the quietest, fastest, smallest and sexiest drives Commodore ever made for the C64 and C128. And it deserves the highly regarded status it has earned over these past 30+ years.