Secondary Storage Device

 

Write short note on Webcam, HDD, CD-ROM, DVD-ROM, Pen drive, Peripherals Device.

Answer:Webcam: A webcam is a video camera that feeds or streams its image in real time to or through a computer to a computer network. When "captured" by the computer, the video stream may be saved, viewed or sent on to other networks travelling through systems such as the internet, and e-mailed as an attachment. In 1991, too many trips to an empty coffee pot led Dr. Quentin Stafford-Fraser and Paul Jardetzky to invent the world's first webcam to help late night studiers and programmers keep an eye on coffee levels.

A webcam is an input device that captures digital images. These are transferred to the computer, which moves them to a server. From there, they can be transmitted to the hosting page. Laptops and desktops are often equipped with a webcam.

a) HDD: A hard disk drive (HDD), hard disk, hard drive, or fixed disk is an electromechanical data storage device that uses magnetic storage to store and retrieve digital information using one or more rigid rapidly rotating disks (platters) coated with magnetic material. The platters are paired with magnetic heads, usually arranged on a moving actuator arm, which read and write data to the platter surfaces.

Hard disk drive Introduced by IBM in 1956. HDDs became the dominant secondary storage device for general-purpose computers by the early 1960s. More than 200 companies have produced HDDs historically, though after extensive industry consolidation most units are manufactured by Seagate, Toshiba, and Western Digital.

b)   CD-ROM: CD-ROM (Compact Disc, read-only-memory) is an adaptation of the CD that is designed to store computer data in the form of text and graphics, as well as hi-fi stereo sound. The original data format standard was defined by Philips and Sony in the 1983. Format of the CD-ROM is the same as for audio CDs: a standard CD is 120 mm (4.75 inches) in diameter and 1.2 mm (0.05 inches) thick and is composed of a polycarbonate plastic substrate (under layer - this is the main body of the disc), one or more thin reflective metal (usually aluminium) layers, and a lacquer coating.

The first CD-ROMs could hold about 600 MB of data, but now they can hold up to 700 MB. CD-ROMs share the same technology as audio CDs, but they are formatted differently, allowing them to store many types of data.

 

c)    DVD-ROM: Digital versatile disc-read only memory (DVD-ROM) is a read-only digital versatile disc (DVD) commonly used for storing large software applications. It is similar to a compact disk-read only memory (CD-ROM) but has a larger capacity. A DVD-ROM stores around 4.38 GB of data. A CD-ROM usually stores 650 MB of data.

A DVD-ROM permanently stores data files which cannot be changed, written over or erased. A personal computer (PC) with a DVD-ROM or a DVD-RAM drive is designed to read a DVD-ROM disc. Generally a DVD-ROM disc is not equipped to be used with a DVD drive connected to a home theatre system or television. But many DVD-ROM drives can generally read a DVD movie disc.

d)   Pen Drive: A pen drive is a portable Universal Serial Bus (USB) flash memory device for storing and transferring audio, video, and data files from a computer. As long as the desktop or laptop has a USB port, and the pen drive is compatible with the operating system, it should be easy to move the data from the hard drive to the device - and to another computer - in a matter of minutes. The drive gets its name from the fact that many have a retractable port connector like a ballpoint pen, and they are small enough to fit into a pocket. Other names include flash drive, jump drive, and thumb drive. Pen drive is like the Hard Disks. But the capacity of pen drive is not as much that if a Hard Disk. Pen drives are small in size with small capacity of storage no comparison to hard disk. Pen drive is very much popular for data transfer.

e)   Peripherals Device: Computer Peripherals are added to computer system to increase its capability and diversity. A peripheral is a device attached to a computer but not part of it, and is more or less dependent on the computer. It is just an extension of any computer system.It expands the capability of a computer, but does not form part of the core computer architecture. There are two types of peripherals: Input and Output

Examples are computer printers, image scanners microphones, speakers, webcams, digital cameras etc. 

What are the differences between RAM and ROM?

Answer: Difference between RAM and ROM:

RAM	ROM
Meaning: RAM-random access memory.	Meaning: ROM-read only memory
This memory can read and write	It is read only memory
It is power dependent memory	It is not power dependent memory
The stored data in a RAM can be changed	The stored data in a ROM cannot changed
Performance of a computer depend on RAM.	Performance of a computer does not depend on RAM.

 

Write a short note on-Monitor, Motherboard, ALU,Control unit.

Answer:

Monitor: It is not required to mention that it is one of the most important Components of your computer. The computer monitor is your computers display device and in most of the cases, the only source of output from your computer. There are two types of Computer Monitors; they are Liquid Crystal Display (LCD) and Cathode Ray Tube (CRT). LCD computer monitors are the trend now. They provide you with better visual effects and better graphics and display than CRT Monitors.

 

Motherboard: The Motherboard is one of the most important components of any computer system. This is the computer component to which all the computer peripherals and components are importantly, the CPU is mounted on the computer Motherboard. It is nothing but a PCB (Printed Circuit Board). It links all the other main components of a computer system together. Consequently, Mother-boards are sometimes referred to as the "heart" of the computer system.

 

ALU : An arithmetic logic unit (ALU) is a digital circuit used to perform arithmetic and logic operations. It represents the fundamental building block of the central processing unit (CPU) of a computer. Modern CPUs contain very powerful and complex ALUs. In addition to ALUs, modern CPUs contain a control unit (CU).An ALU performs basic arithmetic and logic operations. Examples of arithmetic operations are addition, subtraction, multiplication, and division. Examples of logic operations are comparisons of values such as NOT, AND, and OR.

 

Control unit:This unit controls the all activities of computer. At first it takes an instruction of input device and send to Arithmetic logic unit in order to solve it. After solve problem or provides result it send to memory unit or output device.