principles of information systems, sixth edition hardware: input, processing, and output devices...

Principles of Information Systems, Sixth Edition

Hardware: Input, Processing, and Output Devices

Chapter 3


Hardware Components

• Central processing unit (CPU)• Primary storage (main memory; memory)• Secondary storage• Input devices• Output devices


Hardware Components


Hardware Components in Action

• Step 1: Fetch instruction• Step 2: Decode instruction• Step 3: Execute the instruction• Step 4: Store results


Hardware Components in Action


Processing & Memory Devices


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)


Processing Characteristics and Functions

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

• Microcode: internal, predefined elementary operations in a CPU


Clock Speed


Wordlength and Bus Line Width

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

• Word: number of bits that can be processed as a unit

• Bus lines: electrical paths of data flow


Physical Characteristics of the CPU

• Digital circuits on chips

• Electrical current flows through silicon

• Moore’s Law - transistor density of chips will double every 18 months


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


Moore’s Law


Complex and Reduced Instruction Set Computing

• 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


Memory Characteristics and Functions


Storage Capacity


Types of Memory


Types of RAM

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


Types of ROM

• ROM (read-only memory)• PROM (programmable read-only memory)• EPROM (erasable programmable read-only

memory)


Cache Memory


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


Massively Parallel Processing


Secondary Storage


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


Secondary Storage


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)


Devices

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


Types of Secondary Storage


Magnetic Disks


Storage Area Network


Digital Versatile Disk


Additional Devices and Media

• Memory cards• Flash memory• Expandable storage


Expandable Storage


Comparison of Secondary Storage Devices


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


Input and Output Devices


Input Devices

• Personal computer input devices– Keyboard– Mouse

• Voice-recognition devices• Digital cameras• Terminals


Digital Computer Cameras


Magnetic Ink Character Recognition (MICR) Device


Output Devices

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

– Active matrix– Passive matrix


Printers


Computer System Types


Standards


Selecting and Upgrading Computer Systems

• Hard drive considerations • Main memory considerations• Printer considerations


Price List


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

principles of information systems, sixth edition hardware: input, processing, and output devices...

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