Micropolis 100163-51-8 is a floppy disk controller board, implemented on a 5-by-10-inch PCBA
that plugs into the S-100 bus.
Following the success of the
100085 controller card, Micropolis refined
its floppy controller cards and marketed these advanced cards as the Miropolis
Intelligent Controller™.
Sometimes it was marketed as
Micropolis 1071.
100163 is the base model number and suffixes designate which version of the controller it
is:
100163-51-8 is for 100TPI drives, GCR encoding and dual heads.
100163-52-6 is 100TPI, GCR, single head
100163-53-4 48TPI, MFM, dual head
100163-54-2 48TPI, MFM, single head
100163-55-9 100TPI, MFM, dual head
100163-56-7 100TPI, MFM, single head
This controller could be used with a
Micropolis 1015 or
Micropolis 1115 OEM drive. Also, it is usually shipped
with Micropolis floppy-disk storage subsystems, which use these OEM drives internally, like the earlier
Micropolis 1055
or 1043, 1053 subsystems. A 1055 subsystem, for example, is comprised of two drives with two read/write heads each - but they
share one controller. Further, up to four 1055 subsystems can be daisy-chained to one common controller card.
A unique feature is the 100163-51-8's ability to employ
Group coded recording (GCR)
for data storage on the disk medium. GCR in short is data being frequency modulated in a run length limited (RLL) encoding scheme
combined with error-correction. This way, more data can be packed on disk (areal density) and reading/writing is faster.
A single-sided double-density disk, formatted with Micropolis 77-tracks (at 100TPI) usually stores 630,000 bytes. With GCR this
can be increased to 946,000 bytes single-sided and even 1,892,000 bytes of file space on a double-sided disk.