Hardware: Input, Processing, & Output Devices Chapter 3

Hardware: Input, Processing, &

Output Devices

Chapter 3

Chapter 3 IS for Management2

Hardware

HardwareAny machinery (most of which uses digital circuits) that

assists in the input, processing, storage, & output activities of an information system


Central Processing Unit (CPU)A hardware component that performs computing

functions utilizing the ALU, control unit, & registers Arithmetic/Logic Unit (ALU)

Performs mathematical calculations & makes logical comparisons

Control UnitSequentially accesses program instructions, decodes

them, coordinates flow of data in/out of ALU, registers, primary & secondary storage, & various output devices

Hardware Components (1)


Hardware Components (2)

Registers– High-speed storage areas used to temporarily hold

small units of program instructions & data immediately before, during, & after execution by the CPU

– Primary Storage– Holds program instructions & data (a.k.a. main

memory)


Hardware Components (Figure 3.1)


Execution of an InstructionSee also Figure 3.2

Machine Cycle- Instruction phase- Execution phase

Instruction Phase– Step 1: Fetch instruction– Step 2: Decode instruction

Instruction time: The time to complete the instruction phase.

Execution Phase– Step 3: Execute instruction– Step 4: Store results

Execution time: The time to complete the execution phase.


Machine Cycle TimeSee Figure 3.3

Machine Cycle TimeTime it takes to execute an instruction

Slow machinesMeasured in microseconds (one-millionth of a second)

Fast machinesMeasured in nanoseconds (one-billionth of a second) to

picoseconds (one-trillionth of a second) MIPS

Millions of instructions per second. Pipelining

A CPU operation in which multiple execution phases are performed in a single machine cycle


Clock Speed

Clock SpeedPredetermined rate a CPU produces a series of electronic

pulses. Hertz

One cycle or pulse per second Megahertz (MHz)

Millions of cycles per second


Wordlength

WordlengthNumber of bits the CPU can process at any one time

BITBinary Digit - 0s & 1s that combine to form a “word”

Computer wordWhat the computer processes

MicrocodePredefined, elementary circuits & logical operations

that the processor performs when it executes an instruction.


Bus Line

Bus LinePhysical wiring connecting computer

components Bus Line Width

Number of bits a bus line can transfer at one time.


Moore’s Law (Figure 3.4)

Moore’s Law

A hypothesis that states transistor densities in a single chip will double every 18 months


Instruction Sets

Complex instruction set computing (CISC)A computer chip design that places as many microcode

instructions into the central processor as possible Reduced instruction set computing (RISC)

A computer chip design based on reducing the number of microcode instructions built into a chip to an essential set of common microcode instructions


Byte

Eight bits together that represent a single character of data.

1 2 3 4 5 6 7 8

Bytes are stored in memory. Memory provides working storage for program instructions.

Storage Data is represented in on/off (0/1) circuit states.


Memory Characteristics & Functions (Figure 3.5)

Temporary & volatile: RAM - Random Access Memory

• SRAM• DRAM

Permanent & non-volatile: ROM - Read Only Memory

• PROM• EPROM

Cache memory (See Figure 3.6)High speed memory that a processor can access

more rapidly than main memory.


Multiprocessing

MultiprocessingThe simultaneous execution of two or more

instructions at the same time. Coprocessor

Speeds processing by executing specific types of instructions while the CPU works on another processing activity.


Parallel Processing (Figure 3.7)

Parallel processing– A form of multiprocessing that speeds the

processing by linking several processors to operate at the same time or in parallel

– Splits task to be processed by multiple processors, then solutions are compiled/ combined to provide a result

– e.g., www.google.com uses both cached information & parallel processing via hundreds of desktop computers.


Secondary Storage

Stores large amounts of data, instructions, & information more permanently than main memory.

•Magnetic tape•Magnetic disks•Compact Disk Read-Only•Memory (CD-ROM)•Write Once Read Many - (WORM)•Magneto-optical disks•Redundant Array of Independent / Inexpensive Disks (RAID)

•Optical disks•Digital Video Disks•Memory cards•Flash memory•Removable storage•See Figures 3.9, 3.10, 3.11 & 3.12

Devices for Secondary Storage


Access Methods & Storage Devices Sequential

Data retrieved in the order stored. Direct

Data retrieved without the need to read or pass other data in sequence.

Storage Devices– Sequential Access Storage Devices (SASDs)– Direct Access Storage Devices (DASDs)


Input & Output Devices

Data entryThe process by which human-readable data is

converted into machine-readable form Data input

The process of transferring machine-readable data into the computer system

Source data automationCapturing & editing data where the data is

originally created & in a form that can be directly input to a computer


Input Devices

•PC input devices•Voice recognition devices•Digital computer cameras •Terminals•Scanning devices•Optimal data readers•Magnetic Ink Character Recognition (MICR) •Point Of Sale (POS) devices•Automatic Teller Machine (ATM)•Pen input devices•Light pens•Touch sensitive screens•Bar code scanners


Output Devices

• Display monitors• Liquid crystal displays (LCDs)• Printers & plotters • Computer output microfilm (COM)• Disks & diskettes


Types of Computer Systems (1)

Personal Computers (PCs) or Microcomputers– Small, relatively inexpensive– Desktop , laptop, or notebook– Different degrees of power & cost

• Network Computers for accessing networks, especially the Internet (also known as network appliances)

• Workstations are high-end microcomputers Minicomputers

– Size of a three drawer file cabinet plus peripherals – accommodates several users at one time– Useful for departments of large orgs. or entire mid-size

orgs.



Mainframe Computers – Large & powerful– Shared by hundreds/thousands concurrently– Useful for large orgs., massive transaction processing

(e.g., Internet gateway, credit card authorisation) Supercomputers

– Most powerful– with fastest processing speeds– Useful for massive number crunching (e.g., simulating

wind tunnel)



Computer System ArchitectureThe structure, or configuration, of the hardware

components of a computer system Multimedia Computer System (See Figure 3.17)

– Marriage of sound, animation, & digitized video– What is the multimedia part of the Internet commonly

known as?


Annual Cost of PC Ownership (TCO) (See Figure 3.16)

Hardware 15% Technical support 15% Administration services 15% End user operations 55%


Industry Standards in Common UseComputer standards: reference models used by various

groups to establish interoperability between computer components

• Multimedia Extension (MMX)• Multimedia PC Council (MPC)• Ultimedia Solution• Musical Instrument Digital Interface (MIDI)• Plug ‘n’ Play (PnP)• Small Computer System Interface (SCSI)• Fibre Channel• Personal Computer Memory Card International Association

(PCMCIA)•Universal Serial Bus (USB)•Firewire


Case

Unisys - customer service, pages 132-133

Next ClassChapter Four: SoftwareCase: Gap uses object-oriented programming

pp. 184-185

Documents

Hardware: Input, Processing, & Output Devices Chapter 3