Common removable storage devices
1, PD optical drive
PD optical disc adopts phase-change light mode, and its data reproduction principle is the same as that of CD optical disc. According to the different amount of reflected light, signals are distinguished by 1 and 0. The shape of PD disk is the same as that of CD disk, and it is used in a box to protect the data on the disk.
PD optical disc system adopts cell format widely used in computer and workstation environment, and has the same data structure as floppy disk and hard disk, and also adopts 5 12 bit/cell MCAV format that can be used immediately in computer environment. Compared with CD-R/CD-RW in CLV format, this format can read and write at a higher speed and improve the search speed.
2. Molybdenum (magneto-optical)
From the performance of MO system, it can reach the level of running completely on MO without loading on HDD. This greatly broadens the application field of MO. This also gives Mo a stronger technical vitality and market competitiveness.
At present, the media technology has made the speed, reliability, bit storage price, rewriteable times, archiving time and other aspects of MO discs reach a satisfactory level. These characteristics make MO in an irreplaceable position in the competition with pure optical recording equipment CDRW/DVD-RAM.
3. Active hard disk
Winchester hard disk technology is also used in general mobile hard disk, so it has the basic technical characteristics of fixed hard disk and has a high speed. The average seek time is about12ms, the data transmission rate can reach 10M/s, and the capacity varies from 230MB to 4.7GB Like floppy disks, the removable hard disk can be removed from the drive and replaced, and the storage medium is magnetic alloy disk in the disk.
According to the different capacity, the disk structure of mobile hard disk can be divided into three types: single-sided disk, single-sided disk and double-sided disk, and the corresponding drives can be divided into single-headed, double-headed and four-headed. There are four active hard disk interfaces: built-in SCSI, built-in EIDE, external SCSI and external parallel port. Users can choose different interface modes according to their own needs and computer configuration.
4. USB flash drive
U disk, full name "USB interface flash drive", English name "USB flash drive". The name of USB flash drive comes from a new storage device produced by Netac, which is called "USB flash drive" or "USB flash drive" and is connected through USB interface. After the USB interface is connected to the computer host, the data of the U disk can be put on the computer.
The data on the computer can also be put on the USB flash drive, which is very convenient. After that, the equipment with similar technology can no longer be called "USB flash drive" because Netac has registered a patent, but it is called "USB flash drive" or "USB flash drive" figuratively. Later, the name U disk was widely known because it was simple and easy to remember, but until now, both of them have been common and no longer distinguished.
Extended data:
Features of mobile storage devices:
Mobile storage devices have high integration, fast access speed, convenience and flexibility, excellent cost performance and easy storage. Different from storage media.
Mobile storage devices can be roughly divided into three types: magnetic media storage (such as ZIP, LS- 120, USB mobile hard disk, etc. ), optical media storage (such as CD-RW, dvd, MO) and flash media storage (such as U disk and various flash cards). Magnetic media storage is difficult to popularize because of its high price and many standards.
Optical media storage is a mature mobile storage solution, especially suitable for data exchange between PCs. Flash memory based on semiconductor technology is an ideal mobile storage technology.
It can meet the requirements of low power consumption, high reliability, high storage density and high reading and writing speed in computer applications. It can meet the requirements of ordinary users in terms of price, reliability and capacity, and is also a widely used storage medium in digital consumer products.
Baidu encyclopedia-mobile storage device
Baidu encyclopedia-mobile storage