- Количество слайдов: 43
Unit 1 Computer Systems
Computer Systems Reading Sequence: 1.1 Overview of Computer Systems 1.2 Evolution of Computer Systems 1.3 Data Representation in a Computer System Assessments: Exercise 1
1.1 Overview of Computer Systems 1.1.1 Components of a Computer System - Hardware system - Software system - Operating System Software and Application Software - Network System
A computer is an electronic machine that performs input, processing, storing, and output according to programmed instructions to carry out specific tasks. The modern computer operates in a similar fashion. Input to a computer can be sent through the keyboard or mouse. The computer then processes the input, stores the result, and displays the result via the monitor, speaker, printer, or other output devices. In general, a computer system can be decomposed into the hardware system, the software system, and the network system.
Figure 1 Components of a computer system
Hardware System The hardware system consists of external and internal physical components that enable a computer to accept input, process the input, store data, and produce outputs. Hardware components provide the physical interface to a computer system. The figures below show some external hardware components of a computer.
Figure 2 Hardware components
Figure 3 Components inside the system unit
Software System - Operating System Software and Application Software The operating system software serves as the interface between application software and the hardware components The application software interfaces with the users of the computer system
Figure 4 Interaction among hardware system, operating system software, application software, and users
Operating system software provides instructions to hardware system components. Such as Microsoft Windows, Unix, etc. When an input is entered, the operating system program provides instructions to send the input to appropriate hardware components (CPU) for processing. Then, it provides instructions for the result to be sent to the appropriate output device (CRT).
Application software provides instructions that enable the user to perform specific tasks such as creating presentations, composing written documents, and editing images. Examples of application software programs is Microsoft Word. Application software instructions are handled by the operating system. For instance, when you open a file using Microsoft Word, first the application provides the user-interface for you to specify which file you want to open (for example, the menu bar). Once you have selected the file, the application notifies the operating system that a certain file is needed. The operating system then requests for the file from the hard drive of the computer.
Network System The network system manages how data is transferred from one computer to another and how different components of a network system work together. The diagram below illustrates the network components needed for a computer to communicate to other computer via the Internet.
Figure 5 Network connection components
A network interface card (NIC) sends data from a computer over a network, and collects incoming data sent by other computers A modem is a device that enables data from a computer to be transmitted via phone lines or television cable lines to reach other computers on the Internet. A computer also needs an Internet service provider such as Megaline to enable its connection to the Internet.
1.2 Evolution of Computer Systems 1.2.1 Brief History 1200s—Manual Calculating Devices The first calculation device, the abacus, was used in China. It involved manually moving beads to do calculations.
1600s—Mechanical Calculators Mechanical calculators used wheels, gears, and counters. 1642: Blaise Pascal invented the Pascaline, which is a mechanical calculator. The machine used some principles of the abacus, but used wheels to move counters.
1800s—Punched Cards Punched cards use holes following a specific pattern to represent the instructions given to the machine or stored data. 1834: Charles Babbage designed a new general-purpose calculating device, the Analytical Engine, which is the ancestor of modern computers. It included the essential components of present-day computers, which are input, process, storage, and output of data. Babbage's assistant, Augusta Ada King, would create the instruction routines stored on punched cards to tell the machine what to do. Instruction routines used by the computer are known as "computer programs." She is thus the first female computer programmer, and in her honor, the U.S. Defense Department named the programming language ADA.
1940s—Vacuum Tubes 1945: The first computer prototype using vacuum tubes, ENIAC (Electronic Numerical Integrator and Computer) was designed to calculate trajectory tables for the U.S. Army during World War II, but it was not completed until three months after the war. The first commercially successful computer, UNIVAC was developed by Eckert-Mauchly Computer Corporation
ENIAC - The first electronic computer 1945: The first computer prototype using vacuum tubes, ENIAC (Electronic Numerical Integrator and Computer) was designed to calculate trajectory tables for the U.S. Army during World War II, but it was not completed until three months after the war.
ENIAC - The first electronic computer
ENIAC - The first electronic computer
1950s—Transistors Transistors performed functions similar to vacuum tubes but they were smaller, cheaper, and more reliable. Additionally, they consumed less power. The ability for transistors to replace vacuum tubes was first demonstrated in AT&T’s Bell Laboratories. Transistor-based computers could perform 200,000 to 250,000 calculations per second.
1960s—Integrated Circuits An integrated circuit, also called a “microchip” or “chip,” is a thin slice of silicon packed with microscopic circuit elements such as wires, transistors, capacitors, and resistors.
1970s to Present—Microprocessor The microprocessor combined components of a computer on a microchip. Before the microprocessor was developed, each integrated circuit had to be manufactured for a particular purpose, but now a microprocessor can be manufactured and then programmed for various purposes to other needs.
1970s to Present—Microprocessor The first general-purpose microprocessor, Intel 4004, was developed in 1971 by Ted Hoff.
Pace of Advancement As transistors become smaller, more transistors can be placed on a given chip. In 1965, Gordon Moore, a founder of Intel, one of the largest microchip manufacturers, predicted that the number of transistors that can be put on a microchip will double every 12 months, until physical limitations are reached. This observation was termed "Moore’s Law." Now the exponential growth has slowed down to doubling every 18 months, nevertheless, the rate of growth is still exponential.
Table 1 Number of transistors used in Intel processors over the years (From Intel Site)
1.2.2 Applications of Computer Systems In Education Multimedia - Facilitated Learning Multimedia - the use of computers to present text, graphics, video, animation, and sound in an integrated way Simulation-Based Education Computers can be programmed to generate images and animations that model other systems. These systems can be those that exist in the physical world in which we live (for example, people and objects), as well as those from the imagination (e.g. life on the moon and mythical beings).
Medical Training A 3-D virtual reality (VR) software enables students to practice trauma assessment and treatment on wounded man using their computer. This would eliminate the need to send trainees to the field and expedite the training process. Molecule Modeling Researchers could use a software visualization tool to create 3-D models of chemical molecules and explore their properties.
Military Training 3-D simulations can be used build virtual environments that replicate the interior of military crafts to train engineering officers for material readiness assessment. Using simulations, physical crafts do not need to be used during training, and the number of people that can be trained at one time is not limited. Additionally, training can be provided to persons in different geographic locations.
Virtual training for military personnel
Intelligent Machine-Based Training Computer systems can be programmed to react based on user behavior. For example, to facilitate learning a foreign language. Interactive Learning A computer project involves using Music Toys to engage children in listening, performing, and music-composing tasks. Children can play along with some of the world's most accomplished musicians who are participating in this project.
In Business Supply Chain Management Supply chain management aims to manage and track the supply of raw components, their usage in the manufacturing process, and delivery of finished products to customers. Some supply chain management software applications use mathematical algorithms to improve the flow of the supply chain and minimize inventory.
Project Management Product development information, which includes product requirements, work schedules, project milestones, budgets, and product design need to be organized and tracked to monitor the progress of the project. Software applications are capable of keeping track of the product database, work schedule, and budget of the project to help you pinpoint potential barriers to the timely completion of the project.
Customer Relationship Management Customer relationship management (CRM) is a process that gathers information about the customer base, marketing effectiveness, and market trends in order to learn more about customers' behaviors. A CRM software system can collect information about customer demographics, and investigate customer-purchasing behaviors with the objective of predicting customer needs and increasing revenues.
Sales and Marketing Using Electronic Commerce Using the Internet, commerce can be conducted online through the World Wide Web. Manufacturing Research Computer simulation tools can be used to design products.
In Entertainment Movies Video Games Music Digital Photography Travel Wearable Computer Systems Computer systems can also be embedded in devices that are more portable such as a wristwatch or a headphone.