In-depth understanding of the hard disk structure

Opened an in-depth understanding of the hard disk data recovery must be preceded by the overall physical structure of the hard disk have a full understanding. As a high precision parts, hard disk external structure is relatively simple, the real high-tech body in its internal disk. As a high precision parts, hard disk external structure is relatively simple, the real high-tech content in its body within the disc.
1. The external structure of the hard disk 1. The external structure of the hard disk
Hard drive external structure is not complicated, mainly by the power supply interface, data interface, the control circuit board composition. Hard drive external structure is not complicated, mainly by the power supply interface, data interface, the control circuit board composition. For IDE hard drives, Serial-ATA hard drive, SCSI For IDE hard drives, Serial-ATA hard drive, SCSI

Hard drive, its external structure slightly different, which is we need to distinguish between the use of. Hard drive, its external structure slightly different, which is we need to distinguish between the use of.
Power Interface Power Interface
Power Interface used to connect the host power supply for the hard work to provide adequate power. Power Interface used to connect the host power supply for the hard work to provide adequate power. Generally speaking, the hard disk using the most common 4-pin D-shaped power interface. In general, the hard disk using the most common 4-pin D-shaped power supply interface. But should be noted that the latest However be noted that the latest
Serial-ATA hard drive no longer use the D-shaped 4-pin power connector, but instead of using the easy-to-plug interface. Serial-ATA hard drive no longer use the D-shaped 4-pin power connector, but instead of using the easy-to-plug interface. This interface has 15 This interface, 15
A pin, but its width and the previous power interface quite. A pin, but its width and the previous power interface quite. The hard disk controller vendors such as Silicon, Promise, etc. as well as the motherboard manufacturers are packaging their products in turn provides the necessary power wiring, this time can still use the 4-pin D-shaped power supply interface. The hard disk controller vendors such as Silicon, Promise, etc. As well as the motherboard manufacturers are packaging their products in turn provides the necessary power wiring, this time can still use the 4-pin D-shaped power supply interface. From the future development trends, the future can directly extend out Serial-ATA hard drive power connector line, ATX From the future development trend, the future can be extended directly to Serial-ATA hard drive out of line, ATX power connector
Power will become increasingly popular. Power will become increasingly popular.
Data Interface Data Interface
Data interface is a very important part of the hard disk, it is used to connect the South Bridge chip on the motherboard or other independent disk controller chip. Data interface is a very important part of your hard drive, which used to connect the South Bridge chip on the motherboard or other independent disk controller chip. To the most common IDE hard disk, for example, the front of a row of 40 The most common IDE hard drive, for example, the front of a row of 40
Pin interface, through flat IDE data cable to connect the motherboard or RAID / ATA card on the IDE interface. Pin interface, through flat IDE data cable to connect the motherboard or RAID / ATA card on the IDE interface. In the past, old-fashioned hard drives using ordinary 40pin The past, old-fashioned hard drives using ordinary 40pin
Data line, however, the hard disk in order to improve the transmission performance of the major hard drive manufacturers have launched the Ultra DMA transfer mode, that is, we often say ATA66/100/133 Data line, however, the hard disk in order to improve the transmission performance of the major hard drive manufacturers have launched the Ultra DMA transfer mode, that is, we often say ATA66/100/133
The hard disk transfer mode. The hard disk transfer mode. Because of this mode increases the amount of data signal transmission, so have to protect the signal transmission accuracy. Because this mode the transmission of data signals the amount of increase, so have to protect the signal transmission accuracy. In order to improve the electrical performance of IDE data cable, we had to use the 40pin to IDE IDE data lines to improve electrical performance, we had to use 40pin to IDE
Increasing the number of data lines 80pin, which 40pin for signal transmission, while 40pin is the ground used to effectively screen clutter signals. Increasing the number of data lines 80pin, which 40pin for signal transmission, while 40pin is the ground used to effectively screen clutter signals.
Compared with the IDE drives, SCSI hard disk interface is more complex. Compared with the IDE drives, SCSI hard disk interface is more complex. SCSI hard disk interface types can be broadly divided into two 68-pin connector and 80 pin interface, which can directly use the SCSI hard disk interface types can be broadly divided into two 68-pin connector and 80 pin interface, in which the former can be used directly
SCSI controller card to connect, while the 80-pin interface, the product must be used LVD Adapter. SCSI controller card to connect, while the 80-pin interface, the product must be used LVD Adapter. Should be noted that, LVD Adapter, and SCSI data lines to a large extent determine the quality of SCSI Note that, LVD Adapter, and SCSI data lines to a large extent determine the quality of SCSI
Hard drive of play, poor quality of the switch connector performance will be sacrificed. In addition, SCSI hard drive does not require the installation design is similar to the concept of master and slave IDE hard drive, but through the ID number to distinguish. Hard drive of play, poor quality of the switch connector performance will be sacrificed. In addition, SCSI hard drive does not require the installation design is similar to the concept of master and slave IDE hard drive, but through the ID number to distinguish.
In all of the hard drive, Serial-ATA hard drive data cable connection is the most simple, because it uses point to point connections, that each Serial-ATA In all of the hard drive, Serial-ATA hard drive data cable connection is the most simple, because it uses point to point connections, that each Serial-ATA
Cable (or channel) can only connect a hard drive, eliminating the need for IDE hard drive as master and slave jumpers to set the. Cable (or channel) can only connect a hard drive, eliminating the need for IDE hard drive as master and slave jumpers to set the. It is commendable that, Serial-ATA It is commendable that, Serial-ATA
Data lines occupied a small space, which is very conducive to heat dissipation at the same time can improve the stability of data transmission. Data lines occupied a small space, which is very conducive to heat dissipation at the same time can improve the stability of data transmission.
Control circuit board Control circuit board
Control circuit board generally exposed to the hard drive under the surface, in order to facilitate cooling, but there are a few brands of hard drives be completely closed, so you can better protect a variety of control chip, while reducing noise. Control circuit board generally exposed to the hard drive under the surface, in order to facilitate cooling, but there are a few brands of hard drives be completely closed, so you can better protect a variety of control chip, while reducing noise. Hard to control circuit board by the spindle speed circuit, the head drive and servo positioning circuitry, read and write control circuit, control and interface circuits and other accessories. The control circuit board from the hard drive spindle speed circuit, the head drive and servo positioning circuitry, read and write control circuit, control and interface circuits and other accessories. In addition, a high-performance microcontroller In addition, there is a high - performance microcontroller
ROM chip is used to cure software, is used to initialize the hard disk, the implementation of power-up and start the spindle motor, the initial power-seek, locate and fault detection. ROM chip is used to cure software, is used to initialize the hard disk, the implementation of power-up and start the spindle motor, the initial power-seek, locate and fault detection. Of course, the cache is also a control circuit board can not or lacking in general have 2 ~ 8MB SDRAM. Of course, the cache control circuit board is an integral, generally with 2 ~ 8MB SDRAM.

In the drive control circuit board, read and write control circuit is the most important, it has two main functions: First, is responsible for the binary code into an analog signal. In the drive control circuit board, read and write control circuit is the most important, it has two main functions: First, is responsible for the binary code into an analog signal. When the data needed to write, by the central processing system transmitted to heads represent the data in binary code, this circuit is the only way these binary codes, their responsibility is to pass by the binary code is converted to be able to change the current size of the analog signal and transmitted to the head; second is responsible for the analog signals into binary code and amplify the signal. When the data information needs to write, by the central processing system transmission of data to the head is representing the binary code, this circuit is the only way these binary codes, their responsibility is to pass by the binary code is converted to be able to change the current size of the analog signals and transmitted to the head; second is responsible for converting the analog signal into a binary code and amplify the signal. When the read head data obtained from the disc magnetic field generated by the current, Current transfers to the central processing system, we also must go through pre-amplifier circuit, this time the work of this circuit is to represent the current analog signal into a central processing system can identify the binary code, and a weak signal amplification. When the read head data obtained from the disc magnetic field generated by the current, the current transmission to the central processing system, we also must go through pre-amplifier circuit, this time the work of this circuit is the current analog signal will represent the change in as the central processing system can identify the binary code, and a weak signal amplification.

For most of the Serial-ATA hard drive, we can also see an adapter chip. For most of the Serial-ATA hard drive, we can also see an adapter chip. Figure is the Seagate 7200.7 Plus the Serial-ATA Figure is the Seagate 7200.7 Plus a Serial-ATA
Switching chip, it is clear that when the 7200.7 series is not in the development of a true sense of the Serial-ATA hard drive, but by Marvell Switching chip, it is clear that when the 7200.7 series is not in the development of a true sense of the Serial-ATA hard drive, but by the Marvell
To achieve the company's switching chips. To achieve the company's switching chips. chips on the hard disk's role is to drive the source for Health Parallel generated signals are converted to serial signals and transmitted to the system Southbridge chip, or the received sequence of signals are converted to the hard disk can receive parallel signals.chips on the hard disk's role is to drive the source for Health Parallel generated signals are converted to serial signals and transmitted to the system Southbridge chip, or the received sequence of signals are converted to the hard disk can receive signals in parallel. So As a result, the conversion process will inevitably lead to performance loss. In this way, the conversion process will inevitably lead to performance loss. Of course, not to say that the use of adapter chip Of course, not to say that the use of adapter chip
Serial-ATA hard drive a bad idea, but that it is hardly a Serial-ATA hard drive to play the greatest power, we also hope that these chips from the Serial-ATA hard drive disappear. Serial-ATA hard drive a bad idea, but that it is hardly a Serial-ATA hard drive to play the greatest power, we also hope that these chips from the Serial-ATA hard drive disappear.