BYA.SWATHI

I. CPUII. Computer Memory and Mass Storage DevicesIII. Input Technologies & Output Technologies

The CPU or Central Processing Unit is the "brain" of the computer.

Computer CPU's (processors) are composed of thin layers of thousands of transistors.

Because CPU's are so small, they are often referred to as microprocessors. So, the terms processor, microprocessor and CPU are interchangeable.

I. CPU

I. CENTRAL PROCESSING UNIT (CPU)

INPUT DEVICES

OUTPUT DEVICES

CENTRAL PROCESSING UNIT

EXTERNAL STORAGE

MEMORY

The first microprocessor was the Intel 4004, introduced in 1971. The 4004 was not very powerful; it was primarily used to perform simple mathematical operations in a calculator called “Busicom.”

Over the past 40 years, microprocessors have become faster and more powerful, yet increasingly smaller and more affordable.

The manufacturing of a CPU is a highly complex and demanding process involving multiple hundreds of steps in “cleanrooms.” Cleanrooms or manufacturing plants, contain air which is 1,000 times cleaner than a hospital’s operation theatre . The building of one plant costs approximately $5bn.

CPU (contd…)

Arithmetic & Logic Unit Register Array Control Unit

Parts of the CPU:

• Carries out mathematical operation like addition, subtraction etc.

• Carries out logical operations like AND, NOT, OR etc

• Stores data temporarily

• It quickly accepts, store and transfer data and instruction that are used immediately.

• The control unit coordinates the components of a computer system. • All computer resources are managed by the CU

•  It directs the flow of data between the Central Processing Unit (CPU) and the other devices.

Microprocessor attributes: CPU bit width - how many bits it processes in a single

instruction  CPU clock cycles -  how many cycles per second the chip

operates at. CPU execution scores - how many execution cores are in the

chip. Microprocessor companies: -

AMD, IBM, Intel, Motorola, SGI and Sun

CPU (contd…)

II. Computer Memory and Mass Storage Devices

INPUT DEVICES

OUTPUT DEVICES

CENTRAL PROCESSING UNIT

EXTERNAL STORAGE

MEMORY

All computers are based on the binary number system

•A bit or binary digit has one of two values, zero or one• A byte is the smallest addressable unit of memory (8 bits)

American Standard Code for Information Interchange (ASCII).{Standard 8 bit code used in data communications }

Bit - a binary digit e.g. 1 or 0 Byte - a binary word = 8 bits

• 1 Kilo Byte = 1024 bytes• 1 Mega Byte = 1024 KB• 1 Giga Byte = 1024 MB• 1 Tera Byte = 1024 GB

Bits and bytes

• Computer Memory is a temporary storage area•  It holds the data and instructions that the Central Processing Unit (CPU) needs. •Before a program can be run, the program is loaded from some storage medium into the memory. •This allows the CPU direct access to the program. •Memory is a necessity for any computer.• Computer storage can be:

Memory (contd…)

Primary Storage:

1.RAM (Random Access Memory)

2. ROM (Read Only Memory

Secondary Storage Devices:1. Hard Drive2. Floppy Drive3. Zip Drive4. USB Drive5. Compact Disks (CD)6. DVD’s

Read only memory:

Read only memory (ROM) is the permanent memory which is used to store important control programs and systems software to perform a variety of functions, such as booting up or starting up programs. ROM is non-volatile. That means the contents are not lost when the power is switched off. Its contents are permanently written at the time of manufacture.

Random access memory:

Random access memory (RAM) is used as the working memory of a computer system. It stores input data, intermediate results, programs, and other information temporarily. It can be read and written. It is volatile, that is all data will be erased when the power is turned off.

• Mass storage refers to the storage of large amounts of data in a persisting fashion. • These include: • tape libraries• RAID systems• hard disk drives• magnetic tape drives• optical disc drives• magneto-optical disc drives• drum memory  (historic)• Floppy disk drives (historic)• punched tape (historic)

•Mass storage includes devices with removable and non-removable media. It does not include random access memory (RAM), which is volatile in that it loses its contents after power loss.

Mass storage devices

• Hard disk- Is a non-volatile, random-access, magnetic data storage device• Introduced by IBM in 1956• Manufacturers - Western Digital, Seagate, and Toshiba

Do you know what they are loading into the aircraft ?

In September 1956 IBM launched the 305 RAMAC, the first 'SUPER' computer with a hard disk drive (HDD).  The HDD, called IBM 350 Disk Storage Unit, weighed over a ton and stored a 'whopping' 5 MB of data. 

• Tape Libraries - is a storage device which contains one or more tape drives

• These devices can store immense amounts of data, currently ranging from 20 terabytes[1] up to more than 366 petabytes of data

• Eg: Oracle/StorageTek SL8500 tape libraries

• Tape drive - is a data storage device that reads and writes data on a magnetic tape• typically used for offline, archival data storage. Tape media generally has a favourable unit cost and long archival stability.

•RAID- Redundant Array of Independent Disks• a storage technology that combines multiple disk drive components into a logical unit.

III. INPUT & OUTPUT DEVICES

INPUT DEVICES

OUTPUT DEVICES

CENTRAL PROCESSING UNIT

EXTERNAL STORAGE

MEMORY

What are Input and Output devices?

• Input/ Output devices are required for users to communicate with the computer. • In simple terms, input devices bring information INTO the computer and output devices bring information OUT of a computer system. •These input/output devices are also known as peripherals since they surround the CPU and memory of a computer system

Input devices

1.Keyboard2.Point-and-Draw devices3.Scanner

Output devices:

1.Monitor2.Printer3.Plotter

Input devices:

1. Keyboard• It is a text base input device that allows the user to input

alphabets, numbers and other characters.• It consists of a set of keys mounted on a board.• Important Key types:

1. Alphanumeric keys – alphabet, numbers and punctuation2. Modifier keys - are special keys that modify the normal

action of another key, when the two are pressed in combination. Includes Control key, Shift key and the Alt key. 

3. Navigation keys - include a variety of keys which move the cursor to different positions on the screen

Parts of a Keyboard:

Point-and-Draw Devices

• Used to rapidly point to and select a graphic icon or menu item from multiple options displayed on the GUI of a screen• Used to create graphic elements on the screen such as lines, curves and freehand shapes• Common point-and-draw devices include:

Mouse Track ball Joy stickLight pen Touch screen

Mouse

•The mouse is a small device used to point to a particular place on the screen and select in order to perform one or more actions. It can be used to select menu commands, size windows, start programs etc.• The most conventional kind of mouse has two buttons on top: the left one being used most frequently. Mouse Actions

•Left Click : Used to select an item.•Double Click : Used to start a program or open a file.•Right Click : Usually used to display a set of commands.•Drag and Drop : It allows you to select and move an item from one location to another.

Joystick

• Common input device used for video games

Electronic Pen

• Used to directly point with it on the screen to select menu items or icons or directly draw graphics on the screen• can write with it on a special pad for direct input of written information to a system

Touchscreen

•A touchscreen is an easy-to-learn input device. •Enables users to choose from available options by touching with their finger on the desired icon or menu item displayed on the screen.•Touchscreens can also sense other passive objects, such as a stylus. •Touchscreens are common in devices such as game consoles, all-in-one computers, tablet computers, and Smartphone.

Scanners• Input devices that enable direct data entry into a computer system from source documents• 2 types:

Flat-bed scanners Handheld scanners

Optical Character Recognition (OCR) device

•Scanner equipped with character recognition software called OCR software

• Requires less storage for storing because of the storage as text rather than an image

Optical Magnetic Recognition (OMR) device• Scanner capable of recognizing a pre-specified types of mark by pencil or pen• Used widely to scan the results of test or surveys

Magnetic Ink Character Recognition (MICR)

• Used by banking industry for faster processing of large volumes of cheques• Special ink is used that contains magnetizable particles of iron oxide

Electronic Card Reader

• Electronic cards are small plastic cards having encoded data appropriate for the application for which they are used• Electronic card reader is used to read data encoded on an electronic card and transfer it to the computer for further processing• Used in ATMS, Credit cards etc.

Commonly used Output Devices

• Monitors• Printers• Plotters

Monitors

• Electronic visual display device for computers• Most popularly used output device• Monitors can be based on CRT (Cathode Ray Tube), LCD (Liquid Crystal Display) or LED (Light Emitting Diode) technology • The screen resolution denotes the number of pixels that the screen can show; it’s usually written like this: 1920×1080. The higher the numbers, the higher the resolution, and the more detail the screen can handle. In general bigger screens should have higher resolution.•

Printers

• Most common output devices for producing hard-copy output• Types of printers:

1. Dot-matrix printers – form characters and all kinds of images as a pattern of dots

2. Inkjet printers – form characters and all kinds of images by spraying small drops of ink on the paper

3. Laser printers – uses laser technology to print very high quality output

Dot-matrix Inkjet Laser

Plotters• Output device for architects, engineers, city planners and others who need to routinely generate high-precision, hard copy graphical output of widely varying sizes• Types of Plotters

1. a drum plotter draws on paper wrapped around a drum

2. a flatbed plotter draws on paper placed on a flat surface

•Plotters are much more expensive than printers. •They are most frequently used for CAE (computer-aided engineering) applications, such as CAD (computer-aided design) and CAM (computer-aided manufacturing).

Drum plotter

Flat-bed plotter