COMPUTER STORAGE DEVICES

?A computer storage device is any type of hardware that stores data. The most common type of storage device, which nearly all computers have, is a?hard drive. The computer's primary hard drive stores the operating system, applications, and files and folders for users of the computer.While the hard drive is the most ubiquitous of all storage devices, several other types are common as well.?Flash memory?devices, such as USB keychain drives and?iPod nanos?are popular ways to store data in a small, mobile format. Other types of flash memory, such as?compact flash?and?SD?cards are popular ways to store images taken by digital cameras.?(Christensson 2006)

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External hard drives that connect via?Firewire?and?USB?are also common. These types of drives are often used for backing up internal hard drives, storing video or photo libraries, or for simply adding extra storage. Finally, tape drives, which use reels of tape to store data, are another type of storage device and are typically used for backing up data.A storage device may also be known as a storage medium or storage media depending on whether it is seen as discrete in nature (for example, “a hard drive” versus “some hard drive space.”)

Now we look what are the usage of storage devices, A storage device is any type of computing hardware that is used for?storing, porting or extracting data files and objects. Storage devices can hold and store information both temporarily and permanently. They may be internal or external to a computer, server or computing device. A storage

device is a piece of computer hardware?used for saving, carrying and pulling out data. It can keep and retain information short-term or long-term. It can be a device inside or outside a computer or serve.

One purpose of storage devices is?to back up or archive your important data. In the business world, there is a need to store data permanently and in a way that does not get destroyed, corrupted or damaged easily. Different types of storage media can be used for backing up or archiving.

Practically, nearly all computers make use of a storage hierarchy to arrange computer storage. Storage hierarchy puts fast, small yet expensive computer storage devices close to the CPU (Central Processing Unit), while slow, large yet cheap ones far away. n contemporary use, “memory” is usually read and write?random-access memory?(RAM) of semiconductor storage like dynamic RAM (DRAM) and Static RAM (SRAM). Based on the speed, “memory” is divided into processor registers (fastest yet smallest), processor cache, and main memory (slowest yet largest) with registers and cache memory locate inside of the CPU.types of storage are primary storage,secondary storage,tertiary storage and offline storage. Primary storage, also called a prime memory, main memory or internal memory, is often referred to as memory. It is the only directly accessible storage to the CPU, such as?RAM and ROM?(Read-only Memory). The CPU continuously reads instructions saved in the primary storage and executes them as required. All data actively operated on are also saved there in a uniform manner. Secondary storage, also called an external memory or auxiliary storage, differs from the primary storage for its indirectly accessible by the CPU. Computers often rely on input/output (I/O) channels to access the secondary storage and transfer the desired data to the primary storage. Examples of secondary storage devices of computer?are?hard disk drives (HDDs) and solid-state drives (SSDs).

Figure 1-STORAGE DEVICES?THAT?TYPE OF STORAGE ARE PRIMARY STORAGE,SECONDARY STORAGE,TERTIARY STORAGE AND OFFLINE STORAGE.

Tertiary storage, also called tertiary memory, is a level below the secondary storage. Typically, it involves a robotic mechanism that mounts and dismounts removable storage media into computer storage devices under the system requirements. Such kind of data is usually copied to the secondary storage before being used.The tertiary storage is mainly used for archiving rarely accessed data and it is much slower than the secondary storage. The tertiary storage is primarily used for extraordinarily large data storage like tape libraries or optical jukeboxes, accessed without human intervention. Thus, tertiary storage is also known as nearline storage. Magnetic tape, magnetic card and CD/DVD, for example, are all tertiary storage.Kind reminder:

·????????Online storage is immediately available for I/O.

·????????Nearline storage is not immediately available yet can be made online quickly without human operation.

·????????Offline storage is not immediately available and needs human operation to be online.

Offline storage is a kind of computer digital data storage on a media that isn’t controlled by the CPU. The media is usually recorded as a secondary or tertiary storage device and be physically removed or disconnected from its attached computer. To access it again, you must insert or connect it to your computerOffline storage devices are

usually used to data transfer and long-term data storage, and are also called disconnected or?removable computer storage devices. Some examples are floppy disk, magnetic tape, CD and DVD.?(Helen 2006)Also,type of computer storage devices are Magnetic storage devices,Optional storage devices,Flash Memory devices and Online Cloud storage devices\

Magnetic Storage Device?– one of the most popular types of storage used.

Floppy diskette?– A normal 3 ? inch disk can store 1.44 MB of data.Hard drive?– An internal hard drive is the main storage device in a computer. An external hard drive is also known as removable hard drive.?It is used to store portable data and backups.

·????????Magnetic strip?– Magnetic tape drive stores video and audio using magnetic tape, like tape and video tape recorders.

·????????Super disk?– A disk drive and diskette that can hold 120 MB and 240 MB of data.

·????????Cassette tape?– A magnetic storage device used for audio recording and playback.

·????????Zip diskette?– Like a floppy diskette but more advanced.

Optical Storage Device?– uses lasers and lights as its mode of saving and retrieving data.Blu-ray disc?– A digital optical storage device which was intended to replace the DVD format.

·????????CD-ROM disc?– An optical storage device that is read-only or cannot be modified nor deleted.

·????????CD-R and CD-RW disc?– CD-R is a recordable disc that can be written to once, while CD-RW is a rewritable disc that can be written to multiple times.

·????????DVD-R, DVD+R, DVD-RW and DVD+RW disc?– DVD-R and DVD+R are recordable discs that can be written to once, while DVD-RW and DVD+RW are rewritable discs that can be written to multiple times. The difference between the + and – is in the formatting and compatibility.

Flash Memory Device?– is now replacing magnetic storage device as it is economical, more functional and dependable.

·????????Memory card?– An electronic flash memory device used to store digital information and commonly used in mobile electronic devices.

·????????Memory stick?– A memory card that is removable.

·????????SSD – Solid State Drive?– A flash memory device that uses integrated circuit assemblies to save data steadily.

·????????USB flash drive, jump drive or thumb drive?– A small, portable storage device connected through the USB port.

Online and Cloud?– is now becoming widespread as people access data from different devices.

·????????Cloud storage?– Data is managed remotely and made available over a network. Basic features are free to use but upgraded version is paid monthly as a per consumption rate.

·????????Network media?– Audio, Video, Images or Text that are used on a computer network. A community of people create and use the content shared over the internet.?(teachcomputerscience.com n.d.)

Optical discs and flash memory devices?are most popular, and to much lesser extent removable hard disk drives. In enterprise uses, magnetic tape is predominant. Older examples are floppy disks, Zip disks, or punched cards. The most common way of storing movies, songs, software to be distributed and so on is in CDs or DVDs. Due to their low cost per disk, they have become the most common form of storage these days.these are most used storage devices

?Cache:A cache acts a storage medium for storing the data temporarily for easy retrievals in future. Joined on the motherboard and installed on the core processor or the main RAM, this type of storage provides quicker access to the data and the processor does not need to go to the RAM or the hard drive to get the data again and again. Even though it has this great advantage of fast access and retrieval, it is limited by its high expense and limited

RAM:RAM stands for Random Access Memory and is the fastest storage that can attain very high transfer rates of data. Being an example of volatile memory, RAM loses its data when the computer is turned off and hence it requires power to access the data and hence a backup system is mostly used to backup the data. It is basically small in size and has a limited capacity of data storage. RAM can further be classified into static RAM or dynamic RAM depending upon whether the data needs to be refreshed again and again for maintaining it or whether the data holds till the time power is off.Optical drives:The most common way of storing movies, songs, software to be distributed and so on is in CDs or DVDs. Due to their low cost per disk, they have become the most common form of storage these days. Being made of reflective material, such disks are approximately of diameter 4 1/2 inches and have a story capacity of about 600 MB. The major disadvantage is their very short life span.

Pen-drive:The biggest advantage of using pen drive is the fact that they are portable due to their small size and hence can be easily carried anywhere. They are much more robust than the traditional hard drives and are most widely used for backing up data. But because they are relatively expensive per GB, therefore they can be used to backup small amounts of data only. Such flash drives are removable and rewritable and have a memory capacity ranging from about 64 MB to 64 GB.

Floppy disks:Floppy discs are basically circular disks enclosed within a plastic square jacket with the circular disk having a magnetic oxide coating. These can be characterized as Magnetic storage devices that allow easy handling of data. Even though not much data can be stored in such disks, that is only about 1.4 mega bytes , still these were widely used do to their low cost for storing small texts and documents and mostly because of their portability.External hard-disks:Being made of aluminium or other metal alloys and having a coating of magnetic material on both the sides, these disks are portable and can be plugged in and removed from a computer or laptop unlike the hard disc that are permanently attached to a computer. These hard disks have a large storage capacity used to backup data and can be used to store large amount of data ranging from about 160 GB to 3 TB and this is their major advantage over floppy discs for USB pen drives.

Nevertheless, any storage device that provides enough storage capacity and also provides easy retrieval is an idle storage device and can be used to store data and information.?(vskills n.d.)

?(Kaira 2010)There are six main characteristics that we can consider when looking at different types of data. For this, we are going to consider just two scenarios – backing up a whole computer system & moving a file containing homework from home to school:Capacity,speed,portability,Durability.Characteristics of computer storage devices

characteristics

Capacity

Capacity relates to the volume of data that can be stored on a device. In some circumstances, it is important to have a large capacity.

Whole Computer Backup