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CHAPTER 2 C OMPUTER S YSTEMS. 1946-1959. E VOLUTION OF C OMPUTER S YSTEMS. First Generation of Computers. Vacuum tubes. Page 24. 1946-1959. 1957-1963. E VOLUTION OF C OMPUTER S YSTEMS. Second Generation of Computers. Vacuum tubes Transistors. Page 24. 1946-1959. 1957-1963.
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CHAPTER 2 COMPUTER SYSTEMS
1946-1959 EVOLUTION OF COMPUTER SYSTEMS First Generation of Computers • Vacuum tubes Page 24
1946-1959 1957-1963 EVOLUTION OF COMPUTER SYSTEMS Second Generation of Computers • Vacuum tubes • Transistors Page 24
1946-1959 1957-1963 1964-1979 EVOLUTION OF COMPUTER SYSTEMS Third Generation of Computers • Vacuum tubes • Transistors • Integrated circuits Page 25
1946-1959 1957-1963 1964-1979 1980 - present EVOLUTION OF COMPUTER SYSTEMS Fourth Generation of Computers • Vacuum tubes • Transistors • Integrated circuits • VLSI (very-large-scale integrated) circuits Page 25
1946-1959 1957-1963 1964-1979 1980 - present EVOLUTION OF COMPUTER SYSTEMS The Development of Minicomputers Data General DEC Hewlett-Packard IBM Page 26
1946-1959 1957-1963 1964-1979 1980 - present EVOLUTION OF COMPUTER SYSTEMS The Development of Microcomputers Apple IBM PC 1981 Page 26
Page 26-27 Table 2.1 Evolution of Intel Microprocessor
BASIC COMPONENTSOF COMPUTER SYSTEMS Underlying Structure Page 28 Figure 2.4 Logical Structure of Digital Computers
BASIC COMPONENTSOF COMPUTER SYSTEMS Input/Output
BASIC COMPONENTSOF COMPUTER SYSTEMS Input/Output Terminal • Simpler than a PC • Designed strictly for input and output • Has keyboard and screen • Does not have a processor • Connected to computer with telecommunication line • Allows user to key data directly into computer Page 28
BASIC COMPONENTSOF COMPUTER SYSTEMS Input/Output Terminal • Special types: • Point-of-sale (retail) • ATMs (banking) Page 28
BASIC COMPONENTSOF COMPUTER SYSTEMS Input/Output • Common input methods: • Magnetic ink character recognition (MICR) – used to process bank checks • Optical character recognition (OCR) – directly scans typed, printed, or handwritten material • Imaging – inputs digital form of documents and photos • Bar code labeling – scans bar codes on packages or products, and reads into computer Page 29
BASIC COMPONENTSOF COMPUTER SYSTEMS Input/Output • Common output methods: • Print – output to paper using various types of printers • Computer output microfilm (COM) – microfilm generated for archive copies in small space • Voice response units – computer recognizes input, generates verbal response messages Page 29
BASIC COMPONENTSOF COMPUTER SYSTEMS Input/Output Of interest … Multimedia – relatively new term for computer input and output in the form of text, graphics, sound, still images, animations, and/or video Page 29
BASIC COMPONENTSOF COMPUTER SYSTEMS Computer Memory
BASIC COMPONENTSOF COMPUTER SYSTEMS Computer Memory Memory • All data flows to and from memory • Divided into cells: • Each has a unique address • Memory cell types: • Byte – stores one character of data • Word – stores two or more characters of data Page 31
BASIC COMPONENTSOF COMPUTER SYSTEMS Bits and Coding Schemes • Each memory cell is a set of circuits • Each circuit is on or off (represented by 1 or 0) • Each circuit corresponds to a bit (binary digit) • Most computers – 8 bits (circuits) represents a character (byte) • 2 common bit coding schemes used today: • ASCII • EBCDIC Page 32
Bits and Coding Schemes . . . . . . . . . . . . . . . . . . Page 32 Figure 2.4 Computer Coding Schemes
BASIC COMPONENTSOF COMPUTER SYSTEMS Arithmetic/Logical Unit
BASIC COMPONENTSOF COMPUTER SYSTEMS Arithmetic/Logical Unit • Consists of VLSI circuits on a silicon chip • Carries out: • arithmetic – add, subtract, multiply, divide … • logical operations – comparing two numbers Page 33
BASIC COMPONENTSOF COMPUTER SYSTEMS Computer Files
BASIC COMPONENTSOF COMPUTER SYSTEMS Computer Files • When power is off, everything stored in memory is lost • Computer files are used to store data long term • File storage devices: • Magnetic tape drives, disk drives, floppy drives • Optical CD or DVD drives Page 33
BASIC COMPONENTSOF COMPUTER SYSTEMS Computer Files • Sequential access files • Usually stored on magnetic tape drives • Direct access files • Stored on Direct Access Storage Devices (DASD) - magnetic disk drives Page 34
BASIC COMPONENTSOF COMPUTER SYSTEMS Computer Files • Types of DASD • Fixed (hard) drives Page 34 Figure 2.7 Diagram of a Magnetic Disk Drive
BASIC COMPONENTSOF COMPUTER SYSTEMS Computer Files • Types of DASD • Removable: • Floppy drives • Zip drives • Newest: portable DASD for PCs – keychain drive Page 34 Figure 2.8 Iomega’s Mini USB Keychain Drive
BASIC COMPONENTSOF COMPUTER SYSTEMS Computer Files • Newer type of DASD • Optical Disk Storage • CD-ROM 700 megabytes read-only • CD-R recordable • CD-RW rewritable • DVD-ROM 4.7 gigabytes read-only • DVD-R recordable • DVD-RW rewritable Page 36
BASIC COMPONENTSOF COMPUTER SYSTEMS Control Unit
BASIC COMPONENTSOF COMPUTER SYSTEMS Control Unit • Controls computer to take advantage of speed and capacity of other components • Directed by list of operations (program) that tells control unit what to do • Uses the stored-program concept Page 36
THE STORED-PROGRAM CONCEPT • Program – list of what computer needs to do for an application • Instruction – each individual step or operation in a program • Control unit – carries out one step or instruction at a time at electronic speed Page 37
THE STORED-PROGRAM CONCEPT Note:One of the primary measures of power of computers is the number of instructions it can execute in a given period MIPS – millions of instructions per second executed by the control unit MFLOPS – millions of floating point operations per second Page 38
THE STORED-PROGRAM CONCEPT Top Seven Desktop PCs – Power System Page 39 Table 2.2 Benchmarking
EXTENSIONS TO THE BASIC MODEL Communications within the Computer System Terminals Magnetic Tape Units Magnetic Disk Units Page 40 Figure 2.9 Data Channels and Controllers
EXTENSIONS TO THE BASIC MODEL Cache Memory • High-speed storage to temporarily hold data from main memory waiting to be processed • Entire blocks of data moved at one time into cache • Enables CPU to execute much faster • Also incorporated into DASD controllers Page 40 Figure 2.10 Cache Memory
EXTENSIONS TO THE BASIC MODEL Multiple Processor Configurations • Multiprocessor • Symmetric multiprocessor (SMP) • Vector facility • Parallel processor (PP) • Massively parallel processor (MPP) Page 41-42
TYPES OF COMPUTER SYSTEMS Microcomputers Page 43-44
TYPES OF COMPUTER SYSTEMS Workstation/Midrange Systems Page 44-48
TYPES OF COMPUTER SYSTEMS Mainframe Computers Page 48-49
TYPES OF COMPUTER SYSTEMS Supercomputers Page 49