This article summarizes on disk, from learning "Westward store" in the "disk management and technology explain" section.
This article is a summary of theoretical basis of the disk for disk mechanism of deep understanding as will as the gradual improvement of the depth of their learning. I just entry-level storage industry is a little rookie, we will continue to enhance their learning through an open mind.
This article began:
Preface:
What disks are?
Floppy and hard disk can be divided.
What is the floppy disk it? Floppy means: the film package covered with a circular magnetic particles in a plastic case, the intermediate opening, this film is rotated so as to sandwich the motor, which is a floppy disk.
When the floppy disk into the drive, when the motor will drive this disc is rotated while the magnetic head on the magnetic sheet sandwiched between magnet pieces also read and write data. Floppy disks and tapes can be seen as twins, only one is round, it is a belt of. Floppy disk recording is a digital signal, and tape it to record an analog signal. The covered magnetic particles of the magnetic poles on the floppy disk, either N pole or S pole, as when the magnetization strength, as long as the detected N pole magnetic head, will be considered to be 1, if the S pole is detected, it will be considered 0, which is the use of 1 and 0 data recorded to the digital signal. Further, since the disk is designed as a block type, rather than streamed, it is necessary sectorized operations and the like.
What type block it? What is streaming it? - block means is divided into a data block is stored on the medium, can go directly to a data read together, the positioning of the pieces will be faster speed, relatively easy to locate. The flow, refers to data in a continuous manner stored on the media, with no interruption, a bit like a song, save it on tape, the whole song is put up, there is no way to navigate to the song song somewhere to play, only to locate the front or the back of a song.
In general, we use disk-block. Tapes, streaming is used. The above linear recording tape is continuous, but there is a gap between each of the flow, so that the head can be located into this position by the fast-forward directly. However, because of the design, positioning of the tape than disk speed is slow, but the design of the tape, the beginning of time is to meet the needs of large-capacity storage born. For example: We will tape a tangled unfold, it will be larger than the area of a disk, therefore the storage capacity is bound to be greater than the disk.
Although the tape has its own advantages, but the tape can not be used as a real-time data storage media, because it can not locate a block, which also determines the tape can only be used for backup data.
A hard disk structure
The main structure of a hard disk comprising: a base, a disc, a head, a motor, a circuit board or the like. As shown below:
Here are a few selected major description:
1. disc
Generally selected disk substrate made of glass or be made of metal. In order to meet the requirements of high density and high stability, smooth surface of the substrate requires not have any defects. The magnetic powder was then sputtered onto the surface of the substrate crossing, and finally coated with a protective lubricant layer. Here magnetic powder and a higher splash crossing technical requirements. First: producing a very fine and requires no magnetic impurities, second: To a uniform magnetic transition sputtering onto the substrate.
Each disk surface density of the crude referred 32901120000bit, showing its density is very high, so that the disk does not allow any contamination. The production of discs, the entire process required to manufacture in a clean room high cleanliness Class100 carried out, which is to be disassembled in order to be repaired under dust-free environment. Since the magnetic head is floated by a gas flow on the disk, the disk does not come into contact with, and thus moves back and forth at high speed between the tracks, if the head signal read from the disc will be too weak, too low will grinding the surface of the disc, there must be a considerable smooth disc surface, to any foreign matter or dust will rub against the magnetic surface of the magnetic head so that permanently damaged data.
To be continued. . . . .