1581

A 3½-inch double-sided double-density floppy disk drive released by CBM in 1987, primarily for its C64 and C128 home/personal computers. It stores 800 kB using MFM encoding but formats different from the MS-DOS (720 kB), Amiga (880 kB), and Mac Plus (800 kB) formats. With special software it is possible to read C1581 disks on an x86 PC system, and likewise, read MS-DOS and other formats of disks in the C1581 (using Big Blue Reader). It is possible to create “sub-directories”, which in fact are logical partitions with a fixed size.

This unit here comes in its original box with all the accessories that came with it.

Serial: xxxx???

• Type: Floppy disk drive
• Release date: 1987
• Introductory price: USD 399 (1987) USD 1,000 (2022 equivalent)
• Discontinued: 1990
• Media: 3½” floppy disk DS DD using MFM
• Operating System: CBM DOS 10.0
• CPU: MOS 6502 @ 2 MHz, WD1770 or WD1772
• VIA: 8520A
• Memory: 8 kB RAM 32 kB ROM
• Storage: 1MB unformatted, 808.960 bytes formatted (3160 blocks free)
• Image Layout:
  • Directory starts on: T40 S03
  • Disk Header: T40 S00
  • BAM: T40 S01
• Connectivity: Commodore proprietary serial IEEE-488 burst mode with 9.000 bytes/s
• Transfer protocols: Standard and fast serial; burst mode; and commands for parallel interface (the latter not used)
• Coding: MFM
• Format:
  • 80 tracks
  • Ten 512 byte sectors per track
  • 20 logical sectors of 256 bytes
• Power: 220V 50Hz
• Backward compatibility: Commodore 64
• Predecessor: Commodore 1571