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Chapter 3 Hardware and Software Purpose • To be an intelligent consumer of hardware products • To ask intelligent question – What is it? – How can I use it? – Is it the best choice? Agenda • • • • • • • • Computer Hardware Computer Data and Instruction CPU (Central Processing Unit) and Memory Computer Performance Software Computer Virus Discussion and Case Study Computer • Components: hardware and software • Hardware: electronic components and related gadgetry that input, process, output, and store data according to software • Software: instructions encoded in computer programs • Types: general purpose (desk top) and special purpose (cell phone) Hardware - I • Input – keyboard, mouse, document scanner, bar-code scanner, microphone, etc. • Processing – Central processing unit (CPU) – CPU selects instructions, processes them, performs arithmetic and logical comparisons, and stores results of operations in memory – CPU is vary in speed, function, and cost – Special function cards to augment basic capabilities (video display card) Hardware - II • Output – video displays, printers, audio speakers, overhead projectors, etc. • Storage – Save data and program – Magnetic disk, optical disk (CD, DVD), magnetic tape • Communication – Wire, bus, etc. Figure 3-9 Magnetic Disk Components Magnetic Disk • Long-term and nonvolatile data storage • Performance depends on type and size • Recording data on magnetic disk in concentric circles • Read/write head • Data transfer speed – Rotational delay – Seek time – Width and speed of the channel Optical Disk • Type – CD (compact disk) – DVD (digital versatile disk) – The differences are their capacity and speed • Burning a pit into the photosensitive material using a low-power laser to represent data – The presence of a pit causes light to reflect and signifies a one – The absence of reflection signifies a zero • Usage – Playing music and video – Nonvolatile Video Display • Type – CRT (cathode ray tubes) – LCD (liquid crystal display) • Illuminating small spots on the screen called pixels to display image • CRT monitor – The dot pitch: the distance between pixels on the screen – The smaller the dot pitch, the sharper and brighter the screen image • LCD monitor – The pixel pitch: the distance between pixels on the screen – The smaller the pixel pitch, the sharper and brighter the image will be • Optimal resolution – The size of the screen, the dot or pixel pitch, etc. Input, Process, Output, and Storage Hardware Computer Data and Instruction - I • Binary digits (bits) – Zero or one – Closed or open of a switch – Orientation of a magnetic field – Light reflection of a optical media – Represent data and instruction • Byte: 8-bit – Numbers, characters, currency amounts, photos, recordings, or whatever Bits Are Easy to Represent Physically Important Storage-Capacity Terminology Computer Data and Instruction - II • Instruction set: a collection of instructions for directing computer process – Microsoft Windows: Intel instruction set by Intel Corporation – Macintosh computers: PowerPC instruction set using Powerful PC processor – Macintosh computers: either Intel or PowerPC processor starting 2006 CPU and Memory - I • Motherboard: a circuit board mounted and/or connected with processing components • Main memory – – – – – – RAM (random access memory) Volatile A set of cells holding bytes of data or instruction Each cell has a address for identification Speed and amount House OS, application programs, and data CPU and Memory - II • Cache memory – Very fast and expensive memory to improve overall throughput of the CPU – Stores frequently used data, intermediate results, and the most frequently used computer instructions • CPU reads instructions and data from main memory and writes data to main memory via a data channel (bus) • CPU speed – Cycles per second, or hertz (3.0 gigahertz or 3.0 GHz or 3 billion cycles per second) • Data transfer speed – The speed of main memory – The speed and width of the data bus – The wider the bus (by no. of bits), the more data transferring Computer Performance • Memory swapping – A request to the operating system to store data in RAM and there is not enough free memory to store the requested data – The operating system has to remove something to make space – Slow down the performance • Adding more main memory to substantially improve the computer performance Software • Operating system (OS) • Application software Operating System • Types – Windows for business users – Mac OS for arts community – Unix for scientific and engineering community – Linux developed by open-source community for web servers • Own versus License issue Application Software • In terms of source – Off-the-shelf – Custom software • in house or consultant • Difficulty and risky • In terms of capability – Horizontal-market application software for all organization and industry – Vertical-market application software for specific industry • Firmware – Software installed into the device – Print server, communication devices, etc. Computer Virus • A computer program that replicates itself, consumes the computer’s resources, take unwanted and harmful actions • Payload: the program code causing unwanted activity • Type – Trojan horse – Macro virus – Worm • Prevention – – – – – Download Email File extension Antivirus OS patch Discussion • Security (53a-b) – How to enforce employees to follow the antivirus policy and procedure in any organization? – State your opinions related to the statement “the viruses are developed by the antivirus software vendor.” • Opposing forces (57a-b) – State your opinions related to the statement “the new computer products are the conspiracy between hardware and software vendors to ripe off consumers.” • Ethics (61a-b) – State your opinions about the major impacts in terms of social, entertainment, government, and business operations by implementing the TCG/NGSCB (Trusted Computing Group/Next Generation Secure Computing Base) Case Study • Case 3-1 not 6 and 9 (69-70) • Case 3-2 only 1 and 2 (70-71) Points to Remember • • • • • • • • Computer Hardware Computer Data and Instruction CPU (Central Processing Unit) and Memory Computer Performance Software Computer Virus Discussion and Case Study