IBM 3274 51C Maintenance Information page 206

,.
~I-~
- - - - - - - - 1 6 6 . 7 ms
' 1
-t
1-1.5 ms to 3.0 ms
Index
1 •
lll-_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
.L.....J
Head Engagged
\- ~
....................................
'
1------1\ , \
11~.-------80
ms Minimum--------..t,
I
Access 1
~--
__
--~)r,------~--·~I--~~--~I-.~I----4-0-m--s-M-in-i-m-u_m_-_-_-_-_-_.~.-.-.~.'
\{ Ie' \
i ·
I
----,~i
..
~~
..
~I~---------------~l
'u:
I
t
I
. . . . . . l~t . . . . . . ~i-~ . . . . . . . . . . . . . . . . . . .
I
Read/Write Operation
Access 0
iii
i
I
I
I,
I
I
10
I 1
2
' 3 ,
41
I I
I
I
I
Cylinder 0
~~~44
Cylinder 5 ------I~
..
~5
ms
Cylinder to Cylinder Seek Time
Note: Seeking and head loading are not to the index.
Figure E-13. Diskette Operation Sequence
E.2.4 Read/Write Principles
E.2.4.1 Write Data
For each change of the write data signal, the current
switches in the read/write head. This process records the
data on the diskette surface.
Write Data Signal
Recorded Bits
FM Encoding: Writes data bits 4 Ils apart. They are
recorded on the diskette as follows:
Recorded As:
Data Bit to
Be Recorded
Clock
Bit
Data
Bit
1
o
1
o
Data bits 0101 appear as follows:
c o
c c
o
C
f---
4 ps
--I / /
Data Sit
~
No Data Bit
Appendix E. IBM 31SD Diskette Drive Maintenance E-11