Format; Format Parameters; Track Efficiency; Table 4.4.1 Track Efficiency - Fujitsu M2361A Customer Engineering Manual

4.4.2 Format parameters
(1) Gl, G2, G3 (Gap 1, 2 and 3)
Gaps between adjacent areas. They should be filled with all "O"s.
(2) SB (Sync Byte Pattern)
Indicates the beginning of Address or Data Area.
The pattern for both areas can be varied but the recommended pattern is
(19)16 or (OE)16·
(3) AA (Address Area)
The Address Area should contain the following information;
Flag Byte to indicate various conditions of the track or sector, i.e.,
Primary/Alternate track/Sector, Good/Bad track/Sector
• Logical Drive Address
• Cylinder Address
• Head Address
• Sector Address or Record Number
• CRC to check whether the data has been read correctly or ECC to correct
the data when a data error has been detected.
(4) DA (Data Area)
The area where the data should be recorded. CRC or
ECC must be added.
4.4.3 Track efficiency
Table 4.4.1 shows examples of calculated results of track efficiency in
Variable and Fixed Sector Formats. The following assumptions are made for this
calculation.
• The length of Address Area including the SB is 8 Bytes.
• All gap lengths used are the shortest in Figures 4.4.1 and 4.4.2.
• The length of the data area is determined using the formula.
Data Area
=
SB
+
DL (Data Length)
+
CRC
=
1 + DL + 2
=
DL + 3 (Bytes)
• Efficiency
=
DL x (Sector/Track) x 100 (%)
40,960 (Bytes/Track)
0
Table 4.4.1 Track efficiency
~
256
512
Variable Sector/Track
128 71
Sector
Format Efficiency (%) 80.0
88.8
Fixed Sector/Track
128 71
Sector
Format Efficiency (%)
80.0 88.8
B03P-4825-0002A ..• OIA
1
t
024
36
90.0
38
95.0
2,048
19
95.0
19
95.0
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