Specifications

SECTION VI
RECORDING FORMAT
6.1 RECORDING FORMAT (SINGLE DENSITY)
The format of the data recorded on the diskette is totally a function of the host controller. Data is recorded on the
diskette using frequency modulation as the recording mode. i.e., each data bit recorded on the diskette has an
associated clock
bit recorded with it. This is referred to as FM encoding. Data written on and read back from the
diskettes takes the form shown
in figure 6-1. The binary data pattern shown in figure 6-2 represents a "10 1."
6.1.1 Bit Cell
As shown in figure 6-2, the clock bits and data bits (if present) are interleaved. By definition. a bit cell is the period
between the leading
edge of one clock bit and the leading edge of the next clock bit.
CLOCK BITS
DATA BIT
(IF
PRESENT)
f.- BIT CELL ~I
50574·26
FIGURE 6·1. DATA PATTERN
CDC D C
BIT CELLI-:IT CE~
o 1
MSB
BINARY REPRESENTATION OF:
DATA BITS
CLOCK BITS
HEXADECIMAL
REPRESENTATION OF:
DATA BITS
. CLOCK BITS
1 '
..
-
-
BIT CELL
2
o
CLOCK BITS
JLJi)-----?u;L
I
DATA BITS
50574·27
FIGURE 6-2 .. BIT CELL
C CDC
CDC
CDC
-
-
-
- ,-
-
-
- -
BIT CELL BIT CELL
BIT CELL BIT CELL
BIT CELL
3
4
5
6
7
LSB
BYTE
--'"
o
o
o
50574·28
FIGURE 6·3. BYTE
6-1