Computer-Secondary-Memory

 Secondary Memory

Secondary Storage Device is also called Auxiliary Storage Device. It is not part of the computer. It is connected to the computer separately. The data that is stored in it He is permanent. This means that the store data is not deleted when the computer is off. According to the requirement, in future it can be seen by opening the save file or folders. Or improve it. And it can also be deleted by the user. It has more storage capacity in the Secondary Storage Device, which can be stored by multiplying more data than primary memory, which is transferable and access to data is slow and slower than Primary Memory. Secondary Memory comes with floppy disk, hard disk, compact disk, optical disc, memory card, pen drive etc.

Hard Disk

Hard Disk or HDD is the same thing, it is a physical disk that we use to store all the smallest files in our computer. The difference between hard disk and RAM is that, the hard disk is the thing which comes in the store, but RAM comes in handy to run the things stored in that storage. When we turn off the computer, anything that is found in the RAM gets cleared. But when the computer is off in HDD, the data is not erased.

There is a disk rotation inside the hard disk, the faster the disk is faster, the data can be stored or read faster. We measure hard disk rotation speed in RPM (Revolutions Per Minute). Mostly hard disk is 5400 RPM or 7200 RPM, obviously 7200 RPM hard disk is faster than 5400 RPM.

Structure and procedure

Hard disk is made up of magnetic disks. It has a head to read and write data. The hard disk has a central shaft. In which the magnetic disk is attached. Data is not stored on the upper surface of the hard disk and on the lower surface. Data is stored on all other surfaces. There is a Track and Sector in the disc's plate. There is a data store in the sector, one sector has 512 bytes of data store.

There are three types of time to store and read data. Which is low.

1. Seek Time: -. The time taken to access the track in the disk that spins or writes the data is called Seek Time.

2. Latency time: - Time to reach the Sector of data in the track is called Latency Time.

3. Transfer Rate: - The time taken to write and read data in Sector It is called the transfer rate.

Floppy Disk

It is made of plastic on which the layer of ferrite is lying. It is made of very flexible plastic. Therefore, it is called floppy disk. On which is the plastic tomb. The jacket is called. A point is formed between the center of the floppy, from which the disk of the disk rotates. This floppy disk has 80 data track and 64 tracks can be done in each track. It works the magnetic tape for salmon. Which revolves at 360 RPM per minute. This causes a problem with the defect of its recording head.

There are two types of floppy in the form of an eye.

5½ Diameter Floppy Disk

3½ Diameter Floppy Disk

5½ Diameter Floppy Disk - It was invented in 1976 and is also protected from plastic jackets. Its storage capacity ranges from 360 KB to 2.44 MB.

3½ Diameter Floppy Disk - This was used first in Apple Computer. Which is smaller than the previous floppy. Its storage capacity ranges from 310 KB to 2.88 MB.

Magnetic tape

Magnetic tape is also a storage device with a thin lace on which Coading of Magnetic Ink is used to store Analog and Digital Data. It is like the old-time audio cassette, Magnetic Tape is used to store large amounts of data. They are cheap. Even today, it is used to prepare a backup of the data.

Optical Disk

The Optical Disk is a flat, circular polychorbonet disk on which the data is stored in the form of pits within a flat surface, in which the data is stored by the optical.

There are two types of optical discs.

CD: - 

First of all, CD's, CD's, we also call the compact disc, it's an optical medium that saves our digital data. There was a time when we used reel cassettes, the discovery of CDs completely eliminated cassettes in the market. About 700 MB of data can be saved in a standard CD. Data is stored in DOT form in the CD; Actually the laser sensor in the CD drive reads the Reflect Light from the dot in the CD and creates the image in our device.

DVD: - 

DVD is the digital versatile disk, after the CD, although the DVD is debuted, both the CDs and DVDs look the same, but their data capacities differ. More data can be saved on the DVD compared to the CD. . In the DVD, the user can save data from about 4.7 GB to 17 GB. After the arrival of the DVD, there was a huge reduction in the demand for CD in the market.

Blu-Ray Disk:- 

Flash Drive

Pen Drive is known as Flash Drive. Today it is used to store the most Flash Drive data store, it is an External Device which is used separately in Computer. It is also very small and light in size, in which store data can be read and improved.

Flash Drive has a small Pried Circuit Board which is covered with plastic or metal cover, so it is strong. This is a plug-and-play tool. Today it is normally available in 2 GB, 4 GB, 8 GB, 16 GB, 32 GB, 64 GB, 128 GB etc. in capacity.