Samsung HARD DISK DRIVE Service Manual page 26

SAMSUNG HARD DISK DRIVE
Data is recorded on lots of circle in media in HDD, we call these circles track.. We record data
at both sides of media and HDD has many media layers. so it has several tracks which have
Cylinder/Trac
the same radius, we call this concentric circle collection of track Cylinder. Tracks are divided to
k/Sector
sector and it organized ID information and data and ECC. ID information is a sort of address
information to seek data sector requested from host computer.
Data
Separate complex data/clock signal from HDD stored data/timing information encoded form.
Separator
Decoding Restore encoded signal.
Dedicated
Concentrate servo signal (Timing & location control signal) on on side of drive.
Servo
Defect
Find defect and treat data from replaced sector on read/write.
Management
HDD vendor received disks from media vendor for smooth supply and proper price and these
Defect-Free/
media has defect( region can't read write data), by scanning defect during production process
Defect
and replacing normal region so we can product defect-free drive. Defect management means
Management
scanning defect and treatment process from replaced data during read/write.
Disk Head record data in this circle plate, magnetic disk is general.
Disk array Group assembled the separate HDD for large capacity.
Direct Memory Access, data transferring method among system memory and HDD without CPU.
DMA
By using DMA, CPU can do other works while data transferring, efficiency become improved.
DOA dead on arrival, arrival failure.
DPPM Defect parts per million, failure unit.
Drive
Functional definition according to the numbers of head,cylinder,sector per track.
Geometry
DVT Design Verification test.
Error correction code. Correct error data, controller scan and correct error combining user data
ECC
and parity bit.
ECC is Error Correction Code, Additional recording information per every sector. By ECC
ECC creation logic, data is added on disk and checking and correcting with reading. If it is
on-the-Fly correctable error without read action stopping, we call this ECC on-the-Fly with hardware's help
within controller.
E-IDE
Revised interface in IDE way, new specification to improve the existing method has problem of
Enhance
low speed.
IDE
Embedded
Embedded Servo: Arrange servo signal(timing,location control signal) to data and data track in
Servo /
parallel.
Dedicated
information only.
Servo
Encoding is a data transferring method before recording data pattern to disk and Decoding is on
Encoding/
the contrary. To read recorded data more easily and accurately, Encoding and Decoding should
Decoding
be needed. Coding methods are MFM.(2.7)RLL.(1.7)RLL.
VANGO(VL40)
Dedicated Servo: Mechanism of dedicated surface of disk have timing and positioning
D