© Paradigm Publishing Inc. 2-1 Chapter 2 Input and Processing

© Paradigm Publishing Inc. 2-2 Presentation Overview Input Technology Data Processing by Computers The System Unit The Power Supply Storage BaysStorage Bays The Motherboard

© Paradigm Publishing Inc. 2-3 Input Technology Hardware devices are grouped by how and where they are used in the 4 steps of the information processing cycle. –Input –Processing –Output –Storage

© Paradigm Publishing Inc. 2-4 Input Technology What is an input device? A hardware device that allows users to enter programs, data, and commands into a computer system

© Paradigm Publishing Inc. 2-5 Input Technology What are some examples of input devices?

© Paradigm Publishing Inc. 2-6 Input Technology What are some examples of input devices? –Keyboards –Touch screens –Mice and other click devices –Pens and tablets –Optical scanners –Bar code and optical readers –Graphic and video input devices –Audio input devices

© Paradigm Publishing Inc. 2-7 Input Technology A computer keyboard is organized into groups of related keys.

© Paradigm Publishing Inc. 2-8 Input Technology Input Device: Touch Screen allows a user to make selections from a group of options displayed on a screen by pressing a finger on a chosen object

© Paradigm Publishing Inc. 2-9 Input Technology Input Device: Mouse –second most common input device –moving the mouse moves a pointer on screen which allows users to make selections from a menu and activate program icons displayed on screen

© Paradigm Publishing Inc Input Technology Every movement of the mouse corresponds to the movement of the mouse pointer on the display screen.

© Paradigm Publishing Inc Input Technology With a touch pad, the user traces a finger on the pad, moving the pointer on the screen. Below the touch pad there are buttons for clicking commands.

© Paradigm Publishing Inc Input Technology What are some other input devices that haven’t been mentioned? –Optical scanner –Bar code and optical readers –Digital camera –Webcams –Video cameras –Microphone

© Paradigm Publishing Inc Input Technology A scanner captures text and /or images and converts them into a format the computer can understand for display and storage.

© Paradigm Publishing Inc Input Technology A digital camera captures images by converting them from analog to digital format and storing them on a storage medium. The pictures can be printed or inserted into a document.

© Paradigm Publishing Inc Input Technology A digital video camera can plug directly into a computer to display the recorded video.

© Paradigm Publishing Inc Data Processing by Computers What is a program? –A series of instructions, using a binary system to switch registers on and off –Tells a computer how to perform tasks How to process data How to deliver desired information

© Paradigm Publishing Inc Data Processing by Computers The binary number system uses a condition similar to what happens when an electrical switch is turned on, causing current to flow. In the binary number system, a one (1) represents an “on” state in which there is an electrical charge, and a zero (0) represents an “off” state in which there is no electrical charge.

© Paradigm Publishing Inc Data Processing by Computers ASCII is a coding scheme many computers, including personal computers, use. The EBDIC coding scheme is used mainly on large computers such as IBM mainframe computers.

© Paradigm Publishing Inc Data Processing by Computers Pressing a key generates an electronic signal that is converted into binary form (a byte) and stored in memory. The computer processes the digital signal and displays the character on the screen.

© Paradigm Publishing Inc The System Unit the main part of a personal computer system, containing components necessary for processing information

© Paradigm Publishing Inc The Power Supply connects the computer to AC current and converts the AC current to DC current

© Paradigm Publishing Inc Storage Bays The desktop computer shown contains a CD/DVD drive bay and a hard drive bay.

© Paradigm Publishing Inc The Motherboard holds major processing and memory components, including: Central processing unit to manipulate data System clock to synchronize activities Slots for RAM chips to contain temporary memory ROM chips to contain permanent memory Expansion slots to attach expansion cards Ports to connect input and output devices Buses to communicate between computer components

© Paradigm Publishing Inc The Motherboard The motherboard holds the major processing and memory components, including the CPU, RAM, and ROM chips.

© Paradigm Publishing Inc The Motherboard The Central Processing Unit – interprets and executes the instructions for most computer operations –on a personal computer, it is a single chip called a microprocessor, and all processing functions are contained on it –called a CPU or microprocessor

© Paradigm Publishing Inc The Motherboard The Central Processing Unit –performs a machine cycle, which fetches an instruction decodes the instruction executes the instruction stores the result

© Paradigm Publishing Inc The Motherboard The central processing unit (CPU) contains a control unit, arithmetic/logic unit (ALU), and registers.

© Paradigm Publishing Inc The Motherboard The machine cycle includes the four steps for reading and carrying out an instruction: fetching decoding executing storing

© Paradigm Publishing Inc The Motherboard The Control Unit – directs and coordinates the overall operation of the computer –performs machine cycle functions fetching an instruction decoding an instruction

© Paradigm Publishing Inc The Motherboard The Arithmetic/Logic Unit (ALU) executes (carries out) instructions and performs arithmetic and logical operations on data. It can add subtract multiply divide perform logical operations, such as comparing data items

© Paradigm Publishing Inc The Motherboard Registers – temporary storage location – records result to memory – types instruction registers data registers storage registers

© Paradigm Publishing Inc The Mother- board A comparison of desktop personal computer processors

© Paradigm Publishing Inc The Motherboard A comparison of notebook computer and mobile device processors

© Paradigm Publishing Inc The Motherboard Without pipelining, the computer executes an instruction after the previous instruction completes the machine cycle. This is less efficient.

© Paradigm Publishing Inc The Motherboard Processing speed is improved with pipelining. With pipelining, the computer begins executing a new instruction as soon as the previous instruction reaches the next phase of the machine cycle.

© Paradigm Publishing Inc The Motherboard System Clock –controls timing of all computer operations –speed is measured by number of clock pulses per second, or hertz –one clock cycle is equal to two ticks of the clock –a CPU uses a fixed number of clock cycles to execute each instruction

© Paradigm Publishing Inc The Motherboard A multi-core processor is a CPU that includes more than complete core per physical processor, so a single integrated circuit (silicon chip) contains several processors and their cache memories.

© Paradigm Publishing Inc The Motherboard Random Access Memory (RAM) – temporary memory in which programs and data are stored – performs these functions: accepts and holds program instructions and data acts as CPU’s source for data and instructions and as a destination for operation results holds final processed information until it can be sent to desired output or storage devices

© Paradigm Publishing Inc The Motherboard Measures of data storage

© Paradigm Publishing Inc The Motherboard Computer memory comparisons

© Paradigm Publishing Inc The Motherboard Cache Memory a secondary type of processing storage a holding area where data and instructions most recently called by the processor from RAM are stored shortens processing time

© Paradigm Publishing Inc The Motherboard Memory access times

© Paradigm Publishing Inc The Motherboard RAM chips temporarily store programs and data during the processing stage. On some computers, ROM chips contain permanent storage of the operating system and instructions for managing peripheral devices.

© Paradigm Publishing Inc The Motherboard Flash Memory – can be erased and reused or reprogrammed – used for storing programs and data on handheld computers and devices such as digital cameras, cellular phones, and printers

© Paradigm Publishing Inc The Motherboard Expansion –Expansion slots – openings in motherboard for expansion card –Expansion card – component that adds new functions sound card video card network card modem card

© Paradigm Publishing Inc The Motherboard Expansion cards

© Paradigm Publishing Inc The Motherboard Ports are external plug-in slots that connect devices such as monitors, keyboards, and printers to the system unit. Ports are visible on the back of the system unit.

© Paradigm Publishing Inc The Motherboard Ports an external plug-in slot on a computer used to connect to a peripheral device USB ports connect high-speed devices such as scanners and modems serial ports connect devices such as keyboards and modems parallel ports connect printers video ports connect monitors SCSI ports have faster transmission rates than parallel or serial ports

© Paradigm Publishing Inc The Motherboard Data, as bits, travel along a bus from one computer system location to another, like cars travel along a highway. Bits travel along a bus from memory to CPU, input devices to memory, CPU to memory, and memory to storage devices.

© Paradigm Publishing Inc On the Horizon Based on the information presented in this chapter and your own experience, what do you think is on the horizon?