Transcript Computer Files

MANAGING
INFORMATION
TECHNOLOGY
FIFTH EDITION
CHAPTER 2
COMPUTER SYSTEMS
E. Wainright Martin  Carol V. Brown  Daniel W. DeHayes
Jeffrey A. Hoffer  William C. Perkins
EVOLUTION OF COMPUTER
SYSTEMS
First Generation of Computers
1. Vacuum tubes
1946-1959
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EVOLUTION OF COMPUTER
SYSTEMS
Second Generation of Computers
1. Vacuum tubes
2. Transistors
1946-1959
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1957-1963
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EVOLUTION OF COMPUTER
SYSTEMS
Third Generation of Computers
1. Vacuum tubes
2. Transistors
3. Integrated circuits
1946-1959
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1957-1963
1964-1979
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EVOLUTION OF COMPUTER
SYSTEMS
Fourth Generation of Computers
1.
2.
3.
4.
Vacuum tubes
Transistors
Integrated circuits
VLSI (very-large-scale integrated) circuits
1946-1959
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1957-1963
1964-1979
1980 - present
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EVOLUTION OF COMPUTER
SYSTEMS
The Development of Minicomputers
Data General
DEC
Hewlett-Packard
IBM
1946-1959
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1957-1963
1964-1979
1980 - present
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EVOLUTION OF COMPUTER
SYSTEMS
The Development of Microcomputers
Apple
IBM PC
1981
1946-1959
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1957-1963
1964-1979
1980 - present
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BASIC COMPONENTS
OF COMPUTER SYSTEMS
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Table 2.1 Evolution of Intel Microprocessor
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BASIC COMPONENTS
OF COMPUTER SYSTEMS
Underlying Structure
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Figure 2.4 Logical Structure of Digital Computers
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BASIC COMPONENTS
OF COMPUTER SYSTEMS
Input/Output
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BASIC COMPONENTS
OF 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
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BASIC COMPONENTS
OF COMPUTER SYSTEMS
Input/Output
Terminal
 Special
types:
Point-of-sale (retail)
ATMs (banking)
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BASIC COMPONENTS
OF 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
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BASIC COMPONENTS
OF COMPUTER SYSTEMS
Input/Output
Common output methods:
– 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
 Print
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BASIC COMPONENTS
OF COMPUTER SYSTEMS
Input/Output
Multimedia –
relatively new term for computer input and output
in the form of text, graphics, sound, still images,
animations, and/or video
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BASIC COMPONENTS
OF COMPUTER SYSTEMS
Computer Memory
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BASIC COMPONENTS
OF 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
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BASIC COMPONENTS
OF 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
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Bits and Coding Schemes
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Figure 2.4 Computer Coding Schemes
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BASIC COMPONENTS
OF COMPUTER SYSTEMS
Arithmetic/Logical Unit
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BASIC COMPONENTS
OF COMPUTER SYSTEMS
Arithmetic/Logical Unit
Consists of VLSI circuits
on a silicon chip
Carries out:
– add, subtract,
multiply, divide …
 logical operations –
comparing two numbers
 arithmetic
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BASIC COMPONENTS
OF COMPUTER SYSTEMS
Computer Files
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BASIC COMPONENTS
OF 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
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BASIC COMPONENTS
OF 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
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BASIC COMPONENTS
OF COMPUTER SYSTEMS
Computer Files
Types of DASD
 Fixed
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(hard) drives
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Figure 2.7 Diagram of a Magnetic Disk Drive
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BASIC COMPONENTS
OF COMPUTER SYSTEMS
Computer Files
Types of DASD
 Removable:
Floppy drives
Zip drives
Newest: portable
DASD for PCs –
keychain drive
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Figure 2.8 Iomega’s Mini USB Keychain Drive
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BASIC COMPONENTS
OF COMPUTER SYSTEMS
Computer Files
 Newer type of DASD
 Optical
Disk Storage
 CD-ROM
 CD-R
 CD-RW
700 megabytes
read-only
recordable
rewritable
 DVD-ROM
 DVD-R
 DVD-RW
4.7 gigabytes
read-only
recordable
rewritable
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BASIC COMPONENTS
OF COMPUTER SYSTEMS
Control Unit
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BASIC COMPONENTS
OF 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
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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
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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
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THE STORED-PROGRAM CONCEPT
Top Seven Desktop PCs – Power System
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Table 2.2
Benchmarking
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EXTENSIONS TO THE BASIC MODEL
Communications within
the Computer System
Terminals
Magnetic
Tape Units
Magnetic
Disk Units
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Figure 2.9
Data Channels and Controllers
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Data Channel
A specialized I/O Processor that takes
over function of device communication
from the CPU
Its role is to corrects for speed mismatch
between slow peripheral devices and very
fast CPU
It includes buffer storage
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Controllers
A highly specialized microprocessor that
manages the operation of the attached
devices to free up the CPU and the data
channel from these tasks.
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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
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Figure 2.10
Cache Memory
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EXTENSIONS TO THE BASIC
MODEL
Multiple Processor Configurations
Multiprocessor
Symmetric multiprocessor (SMP)
Vector facility
Parallel processor (PP)
Massively parallel processor (MPP)
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TYPES OF COMPUTER SYSTEMS
Microcomputers
Cost in $
MFLOPS
200-3,000
20-400
Major Vendors
Primary Uses
IBM, Dell,
Personal computing
Hewlett-Packard, Client in client/server
Gateway, Fujitsu, applications
Toshiba
Web client
Small business
processing
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TYPES OF COMPUTER SYSTEMS
Workstation/Midrange Systems
Cost in $
MFLOPS
Major Vendors
3,000-1,000,000 40-4,000 IBM, Dell,
Hewlett-Packard,
Gateway, NEC,
NCR, Fujitsu,
Toshiba, Sun
Microsystems
Primary Uses
Departmental
computing
Specific applications
(office automation,
CAD, other graphics)
Midsized business
general processing
Server in client/server
applications
Web server, file
server, LAN server
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TYPES OF COMPUTER SYSTEMS
Mainframe Computers
Cost in $
MFLOPS
1,000,000 20,000,000
200 8,000
Major Vendors
IBM, Fujitsu,
Groupe Bull,
Unisys
Primary Uses
Large business
general processing
Server in client/server
applications
Large Web server
Widest range of
applications
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TYPES OF COMPUTER SYSTEMS
Supercomputers
MFLOPS
Cost in $
1,000,000 100,000,000
© 2005 Pearson Prentice-Hall
Major Vendors
4,000 IBM, Hewlett100,000,000 Packard, Dell,
Hitachi, Cray,
NEC
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Primary Uses
Numerically intensive
scientific calculations
Very large Web
server
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