Principles of Information Systems, Sixth Edition 1 Hardware: Input, Processing, and Output Devices Chapter 3.

Principles of Information Systems, Sixth Edition

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Hardware: Input, Processing, and Output Devices

Chapter 3


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Chapter 3 Outline• Computer Systems: Integrating the Power of

Technology• Processing and Memory Devices: Power, Speed

and Capacity– memory characteristics and functions

• Secondary Storage• Input and Output Devices: The Gateway to

Computer Systems• Computer System Types, Standards, Selecting

and Upgrading


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Computer Systems: Integrating the Power of

Technology


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Hardware Components•1. Processor (CPU)

•2. Memory (primary storage)

•3. Secondary storage

•4. Input devices

•5. Output devices

•6. Communications devices


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How A Computer Thinks: The Processor•Step 1: Fetch instruction•Step 2: Decode instruction•Step 3: Execute the instruction•Step 4: Store results


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Processing & Memory Devices


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Processing Characteristics and Functions

• Machine cycle time is measured in:– Microseconds (1 millionth)– Nanoseconds (1 billionth)– Picoseconds (1 trillionth)– MIPS (Millions of Instructions Processed per Second)

• Clock speed: electronic pulses affecting machine cycle time– Hertz: one cycle (pulse) per second– Megahertz (MHz): millions of cycles per second

• Microcode: internal, predefined elementary operations in a CPU


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Clock Speed


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Wordlength and Bus Line Width

• Bits (Binary Digits): smallest form of data in a computer

• Wordlength: number of bits that can be processed together as a unit. Equal to the size of the processor’s registers.

• Bus lines: electrical circuits used as central paths for data flow.

• Bus line width: number of “lanes” on the bus available for carrying data. Should match word size.


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Physical Characteristics of the CPU

• Superconductivity - property of certain metals that allows current to flow with minimal electrical resistance

• Optical processors - uses light waves instead of electrical current


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History of Computing: Eniac 5

• Built during WWII: The first electronic computer• Used huge numbers of vacuum tubes.• These often broke down and had to be replaced. • The term “computer bug” comes from the fact

that moths would sometimes get into the vacuum tube arrays and be the source of some of the tubes breaking down.


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Semiconductors or Solid State Electronics

• Using these, Shockley, Bardeen and Brattain (1947) created the first “solid state” transistor, essentially an electronically controlled switch,

• Made using semiconductors but much more durable than a vacuum tube.

• The 2nd generation of computers were the first to use solid state technology.

• Their Central Processing Units (CPUs) were built on large scale circuit boards.


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Integrated Circuits• In 1958, Jack Kilby at Texas Instruments

created the first “Integrate Circuit”, shrinking the size of the semiconductor transistors.

• Integrated circuits (ICs) make possible the creation of complex circuits on a single chip.

• The first IC-based microprocessors (“CPU on a chip”) were manufactured around 1970.

• This led to the creation of the microcomputer.


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Moore’s Law• Intel’s first microprocessor, the 4004, was

manufactured in 1971, had 4 bit words and 1 kilobyte of primary memory.

• The miniaturization of the integration circuits has continued at a rapid, more or less predictable pace since the 1960s.

• Intel’s Gordon Moore, seeing this trend, used it to predict the no. of possible transistors on a chip and/or trends in processing power.

• IC technology will eventually be replaced by some other technology, but should continue for about 10 years.


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Moore’s LawMoore’s Law - transistor density/processing power on an integrate circuit doubles every 18 months


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CISC and RISC

• Complex Instruction Set Computing (CISC) - places as many microcode instructions into the central processor as possible

• Reduced Instruction Set Computing (RISC) - involves reducing the number of microcode instructions built into a chip to an essential set of common microcode instructions


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memory characteristics and functions


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Storage Capacity


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Memory Types

•Random Access Memory (RAM) Types:

–EDO (Extended Data Out) –DRAM (Dynamic RAM) –SDRAM (Synchronous DRAM)

•Read Only Memory (ROM) Types:

–ROM–PROM (programmable ROM)–EPROM (erasable programmable ROM)


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Cache Memory


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Multiprocessing

• Speeds processing by linking hundreds and even thousands of processors to operate at the same time

• Can coordinate large amounts of data and access them with greater speed


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Massively Parallel Processing


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Secondary Storage


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Secondary Storage

• Offers the advantages of nonvolatility, greater capacity, and greater economy

• Access methods, storage capacities, and portability required are determined by the information system’s objectives


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Secondary Storage


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Access Methods

• Sequential: records must be retrieved in order– Devices used are called sequential access

storage devices (SASD)

• Direct: records can be retrieved in any order– Devices used are called direct access storage

devices (DASDs)


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Storage Devices

• Magnetic tapes• Magnetic disks• RAID• Storage area networks (SAN)• Optical disks • Magneto-optical (MO) disks• Digital versatile disks (DVDs)


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Magnetic Disks


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Storage Area Network


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Digital Versatile Disk


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Additional Devices and Media

• Memory cards• Flash memory• Expandable storage


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Expandable Storage


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Comparison of Secondary Storage Devices


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Characteristics and Functionality

• Data - can be human or machine readable• Data entry - converts human readable data into

machine-readable form• Data input - transfers machine-readable data

into the system• Source data automation - capturing and editing

data at its source


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Input and Output Devices


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Input Devices

• Personal computer input devices– Keyboard– Mouse

• Voice-recognition devices• Digital cameras• Terminals


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Digital Computer Cameras


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Magnetic Ink Character Recognition (MICR) Device


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Output Devices

• Display monitors• Printers and plotters• Music devices• Liquid Crystal Displays (LCDs)

– Active matrix– Passive matrix


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Printers


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Computer System Types, Standards, Selecting, and

Upgrading


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Computer System Types


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Computer System Types


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Standards


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Standards


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Selecting and Upgrading Computer Systems

• Hard drive considerations • Main memory considerations• Printer considerations


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Example of Price Lists


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Summary

• Hardware - includes any machinery that assists with the input, processing, and output activities of a CBIS

• Processing speed - often measured by the time it takes to complete one machine cycle

• Primary storage (memory) - provides working storage for program instructions and data

• Common forms of secondary storage - magnetic tape, magnetic disk, compact disk, digital video disk, and optical disk storage


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Principles and Learning Objectives

• Assembling an effective, efficient computer system requires an understanding of its relationship to the information system and the organization. The computer system objectives are subordinate to, but supportive of, the information system and the needs of the organization.

– DESCRIBE HOW TO SELECT AND ORGANIZE COMPUTER SYSTEM COMPONENTS TO SUPPORT INFORMATION SYSTEM OBJECTIVES AND BUSINESS ORGANIZATION NEEDS


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Principles and Learning Objectives

• When selecting computer devices, you also must consider the current and future needs of the information system and the organization. The computer system objectives are subordinate to, but supportive of, the information system and the needs of the organization.

– DESCRIBE THE POWER, SPEED, AND CAPACITY OF CENTRAL PROCESSING AND MEMORY DEVICES.

– DESCRIBE THE ACCESS METHODS, CAPACITY, AND PORTABILITY OF SECONDARY STORAGE DEVICES.

– DISCUSS THE SPEED, FUNCTIONALITY, AND IMPORTANCE OF INPUT AND OUTPUT DEVICES.

– IDENTIFY POPULAR CLASSES OF COMPUTER SYSTEMS AND DISCUSS THE ROLE OF EACH.


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End of Chapter 3

Principles of Information Systems, Sixth Edition 1 Hardware: Input, Processing, and Output Devices Chapter 3.

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