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Chapter 2: Computer Systems. Computer Hardware. The physical pieces of a computer system, such as a central processing unit (CPU), a microprocessor, a printer, a disk drive, or a modem Something you can touch. Evolution of Computer Systems.
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Computer Hardware • The physical pieces of a computer system, such as a central processing unit (CPU), a microprocessor, a printer, a disk drive, or a modem • Something you can touch
Evolution of Computer Systems • First Generation - 1946-1959 - vacuum tubes, rotating drum memory • Second Generation - 1959-1964 - transistors, magnetic core memory • Third Generation - 1964-1979 - integrated circuits, semiconductor memory, operating systems • Fourth Generation - 1979-present - LSI and VLSI circuits, communications
Basic Components of Computers • Input/Output • Computer Memory • Arithmetic/Logical Unit • Computer Files • Control Unit
CPU Control Unit Arithmetic/ Logical Unit Memory Output Input Files
Stored Program Concept • The concept of preparing a precise list of exactly what the computer is to do (this list is called a program), loading or storing this program in the memory of the computer, and then letting the control unit carry out the program at electronic speed. The program must be in a form that the control unit of the computer has been built to understand.
Types of Computers • Microcomputers • Workstations • Midrange computers (minicomputers) • Mainframes • Supercomputers • These categories are listed in general order of increasing size, power, and cost
Network Computer / NetPC • Basic idea of both is a stripped down, less expensive PC for users who will always be connected to a network • Network Computer would have minimal memory, processor, disk storage (perhaps no hard drive) • NetPC (Microsoft) would be more powerful so that Windows could be implemented locally
RISC Chips • Reduced Instruction Set Computing • By working with a reduced instruction set, designers were able to create a smaller, faster chip than had been possible previously • Basis for HP 9000, IBM RISC/6000, Sun SPARCsystem, other high-powered workstations
Cache Memory • Very high speed, high cost storage unit • Used as an intermediary between pieces of the computer that operate at quite different speeds • Example -- between the control unit (microprocessor) and main memory • Example -- between disk drive and data channel
Controller • A hardware device to link input/output or file devices to the CPU and memory of large computer systems • A highly specialized processor which manages the operation of its attached devices to free the CPU from these tasks
Data Channel • A specialized input/output processor (a computer) that takes over the function of device communication from the CPU • The role of the data channel is to correct for the speed mismatch between the slow peripheral devices and the very fast CPU
Symmetric Multiprocessor • Multiprocessor machine in which all of the processors (CPUs) are identical, with each processor operating independently of the others • This design technique is used in most mainframes and an increasing number of midrange machines
Parallel Processor (PP) • A multiprocessor configuration (multiple CPUs installed as part of a single computer system) designed to give a separate piece of the same program to each of the processors so that work on the program can proceed in parallel on the separate pieces
Massively Parallel Processor (MPP) • A parallel processing computer with some large number of parallel processors • 32 or more parallel CPUs if the different CPUs are capable of performing different instructions at the same time • 1000 or more parallel CPUs if the different CPUs must all carry out the same instruction at the same time
Changing Nature of Hardware • Decreasing price/performance ratio -- faster and cheaper • Increasing miniaturization • Increasing multimedia (data, video, sound) • More plug-and-play and portability • Greater management complexity due to linking of distributed, cross-platform technologies
The Information Technology Industry • The Information Technology industry is the largest industry in the world, by far. • Let’s look at the primary players.