Computer Storage devices.......

Once upon a time, man designed a machine for calculations. It is calculator. Then it was necessary to store the calculations. Man wanted to find a technology to store at that time. A storage method could be found for it. Thus, those were created. So, Improved storage devices were used for computers.

A storage device is any type of computing hardware that is used for storing, porting or extracting data files and objects.?(techopedia, n.d.) Storage devices can hold and store information both temporarily and permanently. Storage is a process through which digital data is saved within a data storage device by means of computing technology. so, it is a mechanism that enables a computer to retain data, either temporarily or permanently. They may be,

·??????internal or

·??????external?

to a computer, server or computing device. So, the computers we use everyday have common storage devices. Many devices use storage devices. Storage devices are common in the telephone, the computer, servers, and ATM etc. The operating system of a computer is also stored in it. So it can be used to store digital data and applications which may be in the form of images, video, audio etc.?

We use different storage devices. There are four types of storage. There are,???????????

o??Primary storage

o??Secondary storage

o??Tertiary storage

o??Offline storage?

1.)Primary storage

Primary Storage is the main memory of computers. A primary storage device is a medium that holds memory for short periods of time while a computer is running. It is the component of the computer that holds data, programs and instructions that are currently in use. Primary storage is located on the motherboard. Therefore, data can be read from and written to primary storage extremely quickly. The CPU can process data fast. Main memory is directly or indirectly connected to the central processing unit via a memory bus.?(10- Types of Storage Devices (lecture notes)) There are several types of primary storage devices.

Random access memory (RAM) :- RAM temporarily stores data. Data in RAM will be deleted when the computer is switched off. There are two types of RAM:

??????????????????????????I.?????????DRAM (Dynamic Random Access Memory) :- ?

DRAM is slower than SRAM. DRAM is one kind of RAM we see in modern desktops and laptops.so it is Less expensive, less power consumption and needs to be refreshed thousands of times per second.

????????????????????????II.?????????SRAM (Static Random Access Memory):-

SRAM is faster than DRAM. This is more expensive than DRAM. SRAM is More power consumption does not need to be refreshed.

Read only memory (ROM):-?The data in Read Only Memory is not erased when the computer is switched off. Therefore, it is a Non-volatile Memory. The commands required for booting up a computer are stored in ROM.?(Educational Publications Department, 2014) The computer begins to boot up from ROM. We can’t easily or quickly overwritten or modified ROM.

Cache Memory :- Cache is also called CPU Memory. This acts as the mediator between CPU and Primary Memory. Cache Memory is smaller in capacity than other memories. Data is temporarily stored in them. There are three general cache levels.

• ?L1
• ?L2
• L3

L1 cache or primary cache is extremely fast but relatively small and is usually embedded in the processor chip as CPU cache. L2 cache or secondary cache is often more capacious than L1. Level 3 (L3) cache is specialized memory developed to improve the performance of L1 and L2. So most computers we use come with L3 cache and L2 cache. Older computers came L1 cache.

2.) Secondary storage?

Secondary Storage is the device which stores data and information permanently. but,?It is unable to directly access to the CPU. There are internal storage devices as well as external portable secondary storage devices. It doesn’t erase when electricity is not available.?

?Hard disk Drive: -

Data is stored here by using magnetic field. This is the main memory in a computer. Usually largest data storage device in a computer is hard disk.

It is flat circular plates made of aluminum or glass and coated with a magnetic material.?(hard-disk_technology, -). It creates circular tracks around the disk’s surface then divides each track into sectors. Sectors are organized by the OS into groups, called clusters, then tracks each file’s location according to the clusters it occupies. There are two types of hard disk.

o??Internal Hard disk

o??External Hard disk

????? ?i.?????????Internal Hard disk ?

????????????????????????????????We can’t move the internal hard drive. It is in a computer. So Internal Hard disk is less expensive, bigger, and faster than external hard disk.

??? ?ii.?????????External Hard disk

???????????This is a portability device. It can be connected to a computer when needed. So this is more expensive, slower and smaller than internal hard disk.

3.) Tertiary storage?

This is a level below secondary storage. Tertiary storage comprises high-capacity data archives designed to incorporate vast numbers of removable media.?(computer-science/tertiary-storage, n.d.).

Extraordinarily large data can be stored in Tertiary storage. Tertiary storage is difficult to use because it is usually very slow. It is used to archive data that is not accessed frequently.

Examples:

o Magnetic Tape:-- ?It was used mostly in sever computers for back up due to its larger storage capacity. But tape is not used in day today life as it is slow in reading and writing. So tape is much less expensive than other storages. It is used for storing music in the past.

o Optical Disc:-

Since data stored digitally on a disk is read and written by laser beam, it is called optical media. Optical disc is abundantly used for moving data and information files. But it is less used today. There are several types.

• CD-ROM
• CD-R
• CD-RW
• DVD-ROM
• DVD-R
• DVD-RW
• Blue ray Disc (BD)
• Blue ray RE

And the most common types of optical media are

• Blu-ray Disc (BD) ???????????????????????????????Size 25 - 128 GB
• Compact Disc (CD) ????????????????????????????Size 650 - 900 MB
• Digital Versatile Disc (DVD)???????????????Size 4.7 - 9.4 GB

4.) Offline storage

This is a disconnected portability storage.???Offline storage is the slowest and cheapest option. It is not built into the system. It is also abundantly used for moving data and information files.

Ex:-

1. Floppy Disk: -

Currently we don’t use it for storage because It can't store a lot of data or information. It has a maximum storage capacity of 1.44 MB. A floppy disk is magnetic storage medium for computer systems. So it is portable.?

2.Zip diskette : - ?

This was an advanced version of the floppy disk. It was developed by Iomega. Zip disks were available in 100- and 250-MB capacities. So it were used to store, share and back up large amounts of data.

“With the introduction of new and better storage mediums such as memory sticks and DVD-RWs, along with higher capacity hard disks, the Zip disk became less favored and eventually disappeared from the market. ”(zip-disk, n.d.)

3.USB Flash drive :-

This is very popular storage device in the world. It is easy portability. USB Flash drive can read and write data fast. This memory usually has a capacity of 2GB to 256GB. It is an easy way to transfer and store information.

4. Memory card

This is also very popular around the world. it is smaller in physical size. So, it is a portable device. This is used in digital cameras, mobile phones and computer gaming devices. This has the same function of USB flash drive. However, the method of connecting to the computer is different. Memory cards typically range in size from 2 to 512 GB.

“It provides a permanent and non-volatile medium to store data and files from the attached device.”?(memory-card, n.d.)

Types of computer storage devices

1.Magnetic storage devices

“Magnetic storage is one of the most affordable ways to store large amounts of data.”?(magnetic-storage-definition-devices-, n.d.)

Data is stored here by using magnetic field. We can easily store, write and share with magnetic storage devices.?A few examples include

• hard disk drive
• floppy disk
• magnetic tape.
• Magnetic Drum
• Zip Diskette
• SuperDisk
• MRAM

2.Optical storage devices

Optical media is commonly used to carry data and information. Optical storage devices are used laser technology.

???????????Since data stored digitally on a disk is read and written by laser beam, it is called optical media.?(Educational Publications Department, 2014). We use optical media for data transfer. There are three main types of optical media: CD, DVD, and Blu-ray disc. So it was As mentioned above under that optical media.

• ?CD-ROM
• CD-R
• CD-RW
• DVD-ROM
• DVD-R
• DVD-RW
• Blue ray Disc (BD)
• Blue ray RE

3.Flash Memory devices

A flash drive is a small, ultra-portable storage device. Portable devices such as digital cameras, smartphones, and MP3 players normally use flash memory. Flash memory devices are also used for scientific instrumentation, industrial robotics.

Here are a few examples of flash memory:

• computer's BIOS chip
• CompactFlash (most often found in digital cameras)
• ?SmartMedia (most often found in digital cameras)
• Memory Stick (most often found in digital cameras)
• PCMCIA Type I and Type II memory cards (used as solid-state disks in laptops)
• Memory cards for video game consoles

Flash memory is a type of EEPROM chip, which stands for Electronically Erasable Programmable Read Only Memory.?(computer.howstuffworks, n.d.)

4.Online Cloud storage devices:-

Online cloud storage devices are popular at present Cloud storage is off-site storage that's maintained by a third party. Cloud storage safely and securely saves our data. We can control our Online Cloud storage device via internet. It is easy to use every time. If our computer has no space in memory, then we can use online cloud storage devices. So We can protect important data and information through cloud storage.

???????????“Cloud storage is a cloud computing model that stores data on the Internet through a cloud computing provider who manages and operates data storage as a service.”?(what-is-cloud-storage, n.d.).

????????????There are many Online Cloud storages.

• IDrive.
• Google Drive
• Nextcloud
• pCloud.
• Box
• Microsoft OneDrive.
• SpiderOak
• iCloud.
• Sync
• Icedrive
• ?WorkDrive
• Dropbox

We have to pay for cloud storage. But there are cloud storage companies that offer free storage up to 15 GB.

Most used storage devices

???????????Most used storage devices are devices used to store digital data and transfer it between computers. Those are sold in large quantities every day. In today’s world, we will encounter certain storage devices more often than others. Consumers still utilize USB drives and SD Cards. Those are also most used storages But cloud storage is on the rise in the most used stores. Conversely, floppy disks, Optical media and Magnetic Tape are now obsolete.?

Characteristics of computer storage devices

???????????There are few characteristics of computer storage devices.

o??speed

o??cost per storage unit

o??durability

o??portability

Magnetic storage:

• The main storage device in most computer systems.
• Fast access and retrieval times compared to other storage devices.
• Can be easily damaged.
• Slower access than Solid State Drives.

Optical storage

• A laser reads from and writes.
• Portable
• Data can be store in it from
• Blu-ray is expensive. But CDs and DVDs are not expensive.
• Can lose data when scratched.

Flash Memory

• They have replaced the traditional HDD in some new computers.
• Memory cards are used as a convenient and portable removable storage medium.
• Very compact in size
• High speed of data transfer.
• Low power consumption.

Online Cloud storage

• Automatic sync
• Broad network access.
• Multi-tenancy and resource pooling
• View and edit files from the cloud.
• Security and file encryption.
• Flexible storage capacity at an affordable price.
• Reliable tech support.

********THE END*********

References

10- Types of Storage Devices (lecture notes). (n.d.). In t. lecture.

computer.howstuffworks. (n.d.). Retrieved from computer.howstuffworks: https://computer.howstuffworks.com/virtual-memory.htm

computer-science/tertiary-storage. (n.d.). Retrieved from sciencedirect: https://www.sciencedirect.com/topics/computer-science/tertiary-storage

Educational Publications Department. (2014). Information and Communication Technology-Grade 10. Educational Publications Department.

hard-disk_technology. (-). Retrieved from britannica: https://www.britannica.com/technology/hard-disk

magnetic-storage-definition-devices-. (n.d.). Retrieved from study.com: https://study.com/academy/lesson/magnetic-storage-definition-devices-examples.html

memory-card. (n.d.). Retrieved from techopedia/memory-card: https://www.techopedia.com/definition/2788/memory-card

techopedia. (n.d.). www.techopedia.com/storage-device. Retrieved from www.techopedia.com: https://www.techopedia.com/definition/1119/storage-device

what-is-cloud-storage. (n.d.). Retrieved from aws.amazon.com: https://aws.amazon.com/what-is-cloud-storage/

zip-disk. (n.d.). Retrieved from techopedia: https://www.techopedia.com/definition/10150/zip-disk

zip-disk. (n.d.). Retrieved from zip-disk: https://www.techopedia.com/definition/10150/zip-disk

PE/2019/005

V.P.S.L. Premathilaka.