Micropolis 1015/1016-Series




The Micropolis 1015/1016 series of OEM floppy disk drives consists mainly of drive mechanics assemblies meant to be installed in an OEM drive enclosure. But for end-users and smaller OEMs, Micropolis also offered a ready-to-use drive+enclosure model with the Micropolis 1055, a so called "subsystem".

The earliest entry in the drive family is the single-sided 1006, which was available as single (roman numeral II) and double sided variant (roman numeral IV). The revised and improved update to these drives was named 1106 (not 1016). These updated drives 1106 II and 1106 IV were also nicknamed "Micropolis Safari drives". A next iteration are drives labeled as 1015 and 1016 which came in model variants identified by roman numerals I, II, V and VI, each with a different combination of track stepping, head number and data encoding type (MFM / GCR). Although naming might imply that drives from the Micropolis 1115-Series are closely related, 115 drives were introduced years later and represent a bigger step forward.

Later models and especially the 77-track drive variants (subsequently the family as a whole) have been marketed as the MegaFloppy.

Following the success of the 100085 controller card, the "MegaFloppy" family was Micropolis' first iteration of actual drives and drive-subsystems in 1977/1978. It was followed by the 1040/1050 subsystem series around 1980 which used the 1015 drive series in "MacroFloppy" (35 tracks) and "MetaFloppy" (77 tracks) variants.

MOD I drives have a track density of 48 tracks per inch (TPI) with a total of 35 tracks. MOD II drives have a track density of 100TPI with 77 total tracks. The difference in track density and total tracks results from using a different lead screw in the positioner, a different read/write/erase head, and different components and adjustments on the PCBA.

In 1980, when the market for "quad density" 5.25-inch floppy disks moved towards the 96TPI standard instead of the Micropolis proposed 100TPI, the 1015 series forked a line of 96TPI drives. Models 1015-5 and 1015-6 (stylized with roman numerals as 1015-V and 1015-VI) are FM/MFM encoding drives with one or two read/write heads and Micropolis models 1016-5 and 1016-6 are GCR encoding drives with one or two read/write heads respectively.

Disk media

Floppy disk media used to be manufactured as hard-sectored and soft-sectored. Read more about hard-sector and soft-sector media in the Knowledge base. Within the drive's mechanics a photosensor circuit is used to detect the occurrence of the diskette's index mark (and sector marks, if present ). But the drive's mechanics and electronics are agnostic towards these marks as the interpretation is delegated to the host controller. In operation, the drive's sector/index photosensor circuit will generate a signal for each hole passing the disk's window. The host controller must be able to differentiate the index hole from the sector holes and incorporate these signals into its logics.