Sharp MZ-5500 - Milli - Floppy Disk Interface

7. Mini-floppy disk interface
7-1. General description (MZ-5500)
Every MZ-5500 series personal computer is equipped witll ·a 320KB (formatt e d)
mini-floppy disk interface which can control up to a maximum of four
mini-floppy drive unjts. As there is a mini-floppy disk expansion interface
connector on the back of the machine, it permits external installation of
two more drives for the · MZ-55ll that has one internal drive unit and the
MZ-5521 that has two internal drive units. The MZ-5501 that has no internal
drive unit permits expansion witl, the interna! disk drive unit or four
external drive unit.
Fig.7-1 shows the block diagram of the mini-floppy disk circuit.
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Fig.7-1 Mini-floppy disk interface block diagram
The recorcling surface of the mini-floppy
disk is divided into fo rt y tracks along
the radius (Fig.7-2). Track number
begins from 0 and ends at 39 on both
sides and sec tor number are assig ~ ed
from 1 to 16 on both sides. A specific
point on the disk is represented with
tbe track number and the sector number.
1 t penni ts to record 256 by tes in one
sec t or and read/write is possible in
terms of sector.
fjg.7-2 also shows the soft sector.
1n the ID field is recorded the address
(track, side, sec tor) of the sector.
the information in this ID field is used
to read/write data. Tlle ID field is
Fig.7-2 Disk and software
created during formatting
sec tor example
(initial i zation).