How can you classify storage devices? What are its different ways worked out? - Computer notes (2023)

storage mediumis a device for recording (storing)Information(Data). Recording can be done with virtually any form of energy. A storage device is a hardware device that can storeInformation. There are twostorage devicesused in computers; a primary storage device such asComputerRAM and a secondary storage device such asComputer hard disk.

main memory: – Primary storage is a storage location that holdsmemoryfor a short time while the computer is on. For example, computer RAM (random accessmemory) and cache are both examples of a primary storage device. This type of memory is the fastest type of memory in your computer and is used to store data while using it. For example, when you open a program, data is moved from secondary storage to primary storage. It is also referred to as internal storage and main storage.

secondary storage: – Secondary storage is a storage medium that holds information until it is erased or overwritten, regardless of whether the computer is powered. For example aDiskettedrive andhard diskare both good examples of secondarystorage devices. As can be seen from the image below, there are three different types of memory on a computer, although primary memory is accessed much faster than secondary memory due to price and size limitations. Secondary storage is used on today's computers to store all your programs and your own personal data.

It is also known as external storage and auxiliary storage. The offline storage in Fig could be considered as secondary storage, we have put this in its own category as these media types can be easily removed from the computer and stored elsewhere.

Diskette : It is a circular disc coated with magnetic oxide and surrounded by a square plastic cover (jacket). It comes in a variety of sizes, but the most commonly used floppy disk is 3½. It can store data up to 1.44 MB. Data is written on the disk surface as tiny magnetic spots, creating new data or data previously stored in that location to erase the disk surface. Floppy disks are available in 2 sizes, 3.5 inch and 5.25 inch. Mostly the 3.5 inch floppy disk is used. The 5.25" diskette is stored in a flexible case and is not secure. It can store about 1.2MB of data.

Hard disk :Hard drives are made of aluminum or other metal alloys coated on both sides with magnetic material. Unlike floppy disks, Hark disks cannot be removed from the computer. To conserve storage capacity, multiple disks are packaged together and mounted on a common drive to form a disk pack. A plate is also called a plate.

Magnetic tape:Magnetic tapecan be used to perform both functions - input and output.Magnetic tape is asecondary storage media.Magnetic tapes are used for large computers such asmainframeComputers that store large amounts of data over a long period of time. In the PC you can also use tapes in the form of cassettes. The cost of storing data on tape is low. Tapes are made of magnetic materials that permanently store data. It can be 12.5mm to 25mm wide plastic sheet type and 500meters to 1200meters long coated with magnetic material. The deck is connected to the central processor and information is fed to or read from the tape via the processor. It resembles a cassette recorder.

Advantages of magnetic tape:

•Compact:A 10 inch diameter reel of tape is 2400 feet long and can hold 800, 1600 or 6250 characters in each inch of its length. The maximum capacity of such a tape is 180 million characters. As a result, data is stored on tape in a much more compact manner.

•Economically: The cost of storing characters is very low compared to other storage devices.

•Quickly: Copying data is easier and faster.

•Long-term storage and reusability: Magnetic tapes can be used for long-term storage and a tape can be used repeatedly without data loss.

magnetic plate:You may have seen the vinyl record, which is circular like a disc and coated with magnetic material. Magnetic disks used in computers are made on the same principle. It spins at very high speed in the computer drive. Data is stored both on the surface of the hard drive. Magnetic plates are most popular fordirect accessstorage medium.

Each disc consists of a series of invisible onesconcentric circlescalledSense. Information is recorded on tracks on a disk surface in the form of tiny magnetic spots. Represents the presence of a magnetic spota little bitand its absence represents a zero bit. The information stored on a floppy disk can be read many times without affecting the stored data. The reading process is therefore non-destructive. However, if you want to write new data, the existing data will be erased from the hard drive and new data will be recorded.

optical disc: Information is written on or read from an optical disk or tape using a laser beam. Optical disks are not suitable storage devices because their access time is longer than that of hard disks. Their advantage is that they have a very high storage capacity.

Types of optical storage are: CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-R and DVD-RW. Information on a CD-ROM is written at the time of manufacture. 700MB CD-R/W are available. A DVD-ROM is similar to a CD-ROM. It uses a shorter wavelength of laser beam and therefore stores more data than a CD-ROM.

With every new application and software, the need for storage capacity increases. It is the need to store large amounts of data that has led to the development of optical disk storage media. Optical discs can be divided into the following categories:

1.CD/read-only memory(CD-ROM): CD-ROMs are made of reflective metals. CD-ROM is written at high power during the manufacturing processLaser beam.Here the storage density is very high, the storage costs are very low and the access time is relatively fast. Each hard drive is approximately 4 1/2 inches in diameter and can hold over 600MB of data. How the CD-ROM can beread-onlyWe cannot write or change the data contained therein.

2.Write Once Read Many (WORM): The inconvenience that we cannot write anything on a CD-ROM is avoided in WORM. A WORM allows the user to permanently write data to the hard drive. Once the data is written, it can never be erased without physically damaging the hard drive. Data from the keyboard, video scanner,OCRequipment and other devices. The advantage of WORM is that it can store huge amounts of data in gigabytes (109 bytes). Each document in a WORM can be accessed very quickly, say less than 30 seconds.

3.Erasable optical disc: These are optical discs on which data can be written, erased and rewritten. This also applies a laser beam to write and rewrite the data. These panels can be used as an alternative to traditional panels. Erasable optical disks are based on a technology known asmagnetic optical(MO). To write a bit of data onto the erasable optical disc, the MO drive's laser beam heats and magnetizes a tiny, well-defined spot on the disc's surface.