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

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

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

© Paradigm Publishing, Inc. 2-4 Input Technology What is an input device? –An input device is 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? –Keyboards and touch screens –Mice and other point-and-click devices –Pens and tablets –Optical scanners –Bar code and optical readers –Graphic and video input devices –Audio input devices

© Paradigm Publishing, Inc. 2-6 Input Technology A computer keyboard is organized into groups of related keys.

© Paradigm Publishing, Inc. 2-7 Input Technology A touch screen allows a user to make selections from a group of options displayed on a screen by pressing a finger against the chosen option.

© Paradigm Publishing, Inc. 2-8 Input Technology Moving a mouse moves a pointer on the screen which allows users to make selections from a menu and activate program icons displayed on screen.

© Paradigm Publishing, Inc. 2-9 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? –Optical scanner –Bar code and optical reader –Digital camera –Webcam –Video camera –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 then be printed or inserted into a document.

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

© Paradigm Publishing, Inc Data Processing by Computers What is a program? –A program is a series of instructions that use a binary system to switch registers on and off. –A program tells a computer how to perform tasks, including 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 system, a 1 represents “on” and a 0 represents “off.”

© Paradigm Publishing, Inc Data Processing by Computers ASCII is a coding scheme many computers, including personal computers, use. The EBCDIC coding scheme is used mainly on IBM servers and 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 system unit is the main part of a desktop computer system. It contains the components necessary for processing information.

© Paradigm Publishing, Inc Power Supply Like other electronic devices, a computer requires a power supply to supply energy to the computer. –Many personal computers use a power cord that connects the computer to AC current. –The power supply unit in the system must then convert the current from AC to DC.

© Paradigm Publishing, Inc Storage Bays A storage bay is a site where a storage device is installed. The desktop computer shown contains a CD/DVD drive bay and a hard drive bay.

© Paradigm Publishing, Inc The Motherboard A motherboard is a thin sheet of fiberglass or other material with electrical pathways. It holds the major processing and memory components, including –The central processing unit, to manipulate data –The system clock, to synchronize activities –Slots for RAM chips to contain temporary memory

© Paradigm Publishing, Inc The Motherboard A motherboard is a thin sheet of fiberglass or other material with electrical pathways. It holds the major processing and memory components, including –ROM chips to contain permanent memory –Expansion slots to attach expansion cards –Ports to connect input and output devices –Buses that allow communication 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 motherboard contains the central processing unit (CPU). –The CPU interprets and executes the instructions for most computer operations. –In a personal computer, the CPU is a single chip called a microprocessor, and all processing functions are contained on it.

© 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 machine cycle includes the four steps for reading and carrying out an instruction. –Fetching –Decoding –Executing –Storing

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

© Paradigm Publishing, Inc The Motherboard The control unit on the CPU –Directs and coordinates the overall operation of the computer –Performs the first two machine cycle functions Fetching an instruction Decoding an instruction

© Paradigm Publishing, Inc The Motherboard The arithmetic/logic unit (ALU) on the CPU –Performs the executing step of the machine cycle The ALU can –Add/subtract –Multiply/divide –Perform logical operations, such as comparing data items

© Paradigm Publishing, Inc The Motherboard The registers on the CPU –Are a temporary storage location (the storing step of the machine cycle) –Record results to memory Types of registers include –Instruction registers –Data registers –Storage registers

© Paradigm Publishing, Inc The Motherboard The power and speed of microprocessor (CPU) chips are determined primarily by –The number of transistors –The clock speed –The number of bits that can be handled as a single unit

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

© Paradigm Publishing, Inc The Motherboard A dual-core processor is a CPU that includes two complete cores per physical processor. This means that a single integrated circuit (silicon chip) contains two processors and their cache memories.

© Paradigm Publishing, Inc The Motherboard The system clock controls timing of all computer operations. –Its 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 Random access memory (RAM) is temporary memory in which programs and data are stored. –RAM performs three functions: It accepts and holds program instructions and data. It acts as the CPU’s source for data and instructions and as a destination for operation results. It holds the final processed information until it can be sent to the desired output or storage devices.

© 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 Measures of Data Storage

© Paradigm Publishing, Inc The Motherboard Computer Memory Comparisons

© Paradigm Publishing, Inc The Motherboard Cache Memory –A holding area in which the data and instructions most recently called by the processor from RAM are stored. –Helps to shorten processing time.

© Paradigm Publishing, Inc The Motherboard Memory Access Times

© Paradigm Publishing, Inc The Motherboard Flash memory can be erased and reused, or reprogrammed. This type of memory is used for storing programs and data on handheld devices such as digital cameras and cellular phones.

© Paradigm Publishing, Inc The Motherboard Expansion –An expansion slot is an opening in the motherboard for an expansion card. –An expansion card is a component that adds a new function. Examples include Sound cards Video cards Network cards 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. –Are visible on the back of the system unit.

© Paradigm Publishing, Inc The Motherboard Types of Ports –USB ports, which connect high-speed devices such as scanners and modems –Serial ports, which connect devices such as keyboards and modems –Video ports, which connect monitors –Network ports, which connect computer systems to local area networks

© Paradigm Publishing, Inc The Motherboard Data, as bits, travel along a bus from one computer system location to another. 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?