Z-100 Floppy Drives

Since the first single side, single density (SSSD), 8" floppy drives were placed in service for the early computers in the late 1970s, there have been several advancements developed:

  • Single Side, Single Density (SSSD), 48tpi 5.25"
  • Double Side, Double Density (DSDD), 48tpi 5.25"
  • Double Side, High Density (DSHD), 96tpi 5.25"
  • Double Side, Double Density (DSDD), 67tpi 3.5"
  • Double Side, High Density (DSHD), 135tpi 3.5"
  • 2" microfloppy, and others, including optical drives.

This article will concentrate on the most popular floppy drives used in the Z-100 computer series.

Note:  For easier reading and simplicity, I’m going to refer to the drives and disks as 8", 5" and 3", omitting the decimals. I’m also going to refer to the Z-DOS operating system and monitor ROM (ZROM) versions as v2, v3, and v4, again dropping the decimal intermediate versions.


          Z110PIC          Z120PIC

                            Z-110 Low-Profile                                                               Z-120 All-In-One


While the first floppy drives found within the Z-100 were the 5", 48tpi, single side, single density (SSSD), full height drives, like those shown here, within a short period, the most popular configuration of drives marketed in the Z-100 was a pair of double side, double density (DSDD) half height 5" drives or a single DSDD half height 5" drive with a “Winchester” 10Mb hard drive.

The 50-pin connector on the Z-207 Floppy Controller could also accommodate an external 8" drive.

The standard Z-100 Floppy Disk Controller could use up to four single or double density drives on the 34-pin connector and another four high density drives on the 50-pin connector. The Z-100 series computer could also use two floppy controllers, for up to 16 floppy drives!

However, the software of the period, Z-DOS and CP/M could only accommodate a limited number of drives at a time. As a default, the drive letters, A: and B: were assigned to the standard 5" floppy drives. The drive letters, C: and D: were assigned to the 8" variety of drives on the 50-pin connector. And the drive letters, E: through H: were assigned to any hard drive partitions, if installed.

In order to use other drives, the drive letters would have to be reassigned, using the ASSIGN command.

Note:  With Z-DOS v4, the drive letters A: through Z: could be assigned as desired through the DRIVECFG utility.

All in all, the Z-100 series computer was very flexible when it came to the use of floppy disk drives.

Note:  In 1989 William E. Flanagin developed DiskPack, a Floppy Disk Device Driver for the Z-100 computer that changed everything. It was a software package, marketed by Paul Herman, which allowed the use of all popular 8", 5", and 3" floppy disk formats, including many strange formats used by other computer systems, and PC-compatible formats. Email “Z-100 LifeLine” for additional information.

For more information with drive specifics, such as setup and configuration, please refer to my article: Z-100 Floppy Drives.