Data Format 3-6 C141-E237
Head
Track skew
Track skew
Head skew
Leading logical
sector in head p+1
Head
Figure 3.5 Track skew/head skew
The number of physical sectors (track skew factor and head skew factor) corresponding to the skew
time varies depending on the logical data block length because the track skew and the head skew are
managed for individual sectors. The HDDs automatically determine appropriate values for the track
skew factor and the head skew factor according to the specified logical data block length. The value
can be read out by the MODE SENSE or MODE SENSE EXTENDED command after the track has
been formatted.
3.1.4 Sector format
Each sector on the track consists of an ID field, a data field, and a gap field which separates them.
Figure 3.6 gives sector format examples.
SCT
PAD
SM1
PLO
SyncG1
SCT
G2
DATA1 SM2 BCRCDATA2 ECC
SCT
PAD
SM1
PLO
Sync
G1
SCT
G3
DATA1 SM2 DATA3 PAD G2 SM1
PLO
SyncG1 DATA1 SM2 DATA4
Servo
BCRC ECC
Figure 3.6 Sector format