This document discusses the history and evolution of computer systems from the earliest vacuum tube computers of the 1940s to today's integrated circuit-based systems. It covers the four generations of computers based on their underlying technology: vacuum tubes, transistors, integrated circuits, and VLSI chips. It also describes different categories of computer systems including supercomputers, mainframes, minicomputers, microcomputers, and their characteristics and applications.

1. CHAPTER 2
Computer Systems

2. COMPUTER GENERATIONS
1. VACUUM TUBES: 1946-1959

3. COMPUTER GENERATIONS
1. VACUUM TUBES: 1946-1959
2. TRANSISTORS: 1957-1963

4. COMPUTER GENERATIONS
1. VACUUM TUBES: 1946-1959
2. TRANSISTORS: 1957-1963
3. INTEGRATED CIRCUITS: 1964-1979

5. COMPUTER GENERATIONS
1. VACUUM TUBES: 1946-1959
2. TRANSISTORS: 1957-1963
3. INTEGRATED CIRCUITS: 1964-1979
4. VERY LARGE-SCALE INTEGRATED
(VLSI) CIRCUITS: 1980- PRESENT
*

6. SUPERCOMPUTER
TERAFLOP: TRILLION
CALCULATIONS/SECOND
• HIGHLY SOPHISTICATED
• COMPLEX COMPUTATIONS
• FASTEST CPUs
• LARGE SIMULATIONS
• STATE-OF-THE-ART COMPONENTS
• EXPENSIVE
*

7. MAINFRAME
• LARGEST ENTERPRISE COMPUTER
• 5O MEGABYTES TO OVER ONE
GIGABYTE RAM
• COMMERCIAL, SCIENTIFIC,
MILITARY APPLICATIONS
• MASSIVE DATA
• COMPLICATED COMPUTATIONS
*
MIPS: Millions of Instructions per second

8. MINICOMPUTER
• MIDDLE-RANGE
• 10 MEGABYTES TO OVER ONE
GIGABYTE RAM
• UNIVERSITIES, FACTORIES, LABS
• USED AS FRONT-END PROCESSOR
FOR MAINFRAME
*

9. • DESKTOP OR PORTABLE
• 64 KILOBYTES TO OVER 128
MEGABYTES RAM
• PERSONAL OR BUSINESS
COMPUTERS
• AFFORDABLE
• MANY AVAILABLE COMPONENTS
• CAN BE NETWORKED
*
MICROCOMPUTER

10. LAPTOPS & SMALLER
• LAPTOP (OR NOTEBOOK): Briefcase
type package, very portable, can be
inexpensive, can connect to other
computers or networks
• HAND-HELD (OR PALMTOP): Sub-
miniature, wireless computer. Growing
in sophistication and connectivity
*

11. Microcomputer Systems
• By Size
– Handheld: PDA
– Notebook
– Desktop
• By Use
– Home, Personal,
Professional
– Workstation
– Multi-User
• By Special Purpose
– Workstations
– Network servers
– PDA
• Workstation computers support
applications with heavy mathematical
computing and graphics
• Network servers co-ordinate
telecommunications and resource
sharing in LANs, and Internet and
intranet websites
• Network computers (NCs;
thin clients) designed for use with
the Internet and intranets with
specialized or limited computing
applications
• NetPCs: in-between PCs and NCs.
Examples: Dell’s Webpc, HP’s e-PC
• Information appliance offers
users the capability to perform a host
of basic computational chores.
Examples: PDA

12. Midrange Computers
• Midrange computers, including minicomputers and high-
end network servers, are
– multi-user systems that can manage networks of PCs
and terminals
– general-purpose computers that are larger and more
powerful than most microcomputers
• Midrange Computer Applications
– Serve as industrial process-control and manufacturing
plant computers
– Play a major role in computer-aided manufacturing
(CAM)
– Serve as front-end computers to assist mainframe
computers in telecommunications processing and
network management
• Examples: IBM’s AS/400
– RISC processor chips handling 64 bits of data
– Running on OS/400 operating system

13. Midrange Computers
Midrange Computer as Network Server
• Serve as powerful network servers to help manage
large Internet web sites, corporate Intranets and
extranets, and client/server networks
• E-commerce and other business uses of the Internet
are popular high-end server applications, as are
integrated enterprisewide manufacturing,
distribution, and financial applications.
• Data warehouse management, data mining, and
online analytical processing are all contributing to
the growth of high-end servers and other midrange
systems.

14. Mainframe Computer Systems
are physically larger and more powerful than micros and
minis; have large primary storage capacities
• Mainframe Computer Applications
– Handle the information processing needs of major
corporations and government agencies with many
employees and customers
– Used in organizations processing great volumes of
transactions
– Serve as superservers for the large client/server
networks and high-volume Internet web sites of large
companies
– Are becoming a popular business-computing platform
for data mining and warehousing, and electronic
commerce applications
• IBM’s System/390 (up to 12-processor model, memory -
32GB); Fujitsu, Hitachi, NEC, Unisys, Groupe Bull

15. Supercomputer Systems
are designed for scientific, engineering, and business
applications requiring extremely high-speeds for massive
numeric computations
• Supercomputer Applications
– Used by government research agencies, large universities,
and major corporations
– Are used for applications such as global weather forecasting,
military defense systems, microprocessor research and
design, large scale data mining, large time-sharing networks
– Use parallel processing architectures of interconnected
microprocessors
– Can perform arithmetic calculations at speeds of billions of
floating-point operations per second (gigaflops) and teraflop
• Gray T3E (up to 2048 parallel processors, 2.4 teraflops); IBM, Hitachi,
NEC, Silicon Graphics

16. BASIC COMPONENTS OF
COMPUTER SYSTEMS
• UNDERLYING STRUCTURE
• INPUT/OUTPUT
• BITS & CODING SCHEMES
• ARITHMETIC LOGIC UNIT
*

17. CENTRAL PROCESSING UNIT
(CPU)
RAM
PRIMARY (MAIN) MEMORY
CONTROL UNIT
ARITHMETIC/LOGIC
UNIT
ROM
CLOCK

18. BUSES
CPU
PRIMARY
STORAGE
DATA BUS
ADDRESS BUS
CONTROL BUS
INPUT
DEVICES
OUTPUT
DEVICES
SECONDARY
STORAGE

19. TYPES OF MEMORY
• RAM : Random Access Memory
– Dynamic: Changes thru processing
– Static: Remains constant (power on)
• ROM : Read Only Memory
(preprogrammed)
– PROM: Program can be changed once
– EPROM: Erasable thru ultraviolet light
– EEPROM: Electrically erasable
*

20. INPUT/OUTPUT
• TERMINAL
• POINT-OF-SALES TERMINALS
• AUTOMATIC TELLER MACHINES
• PUNCHED CARDS
• MAGNETIC INK CHARACTER RECOGNITION
(MICR): Used by banks to process checks
*

21. INPUT/OUTPUT
• OPTICAL CHARACTER RECOGNITION:
Scanned material translated into computer
characters
• IMAGING: Forms, documents, photos
digitized for computer use
• BAR CODE LABEL: Product label
information read into computer. Can be used
to track inventory
*

22. INPUT/OUTPUT
• COMPUTER OUTPUT MICROFILM (COM):
Computer rapidly generates microfilm
documents for archive copies in small space
• VOICE RESPONSE UNITS: Computer
recognizes, generates verbal messages
• MULTIMEDIA: Combines text, graphics,
sound still images, animations, video
*

23. • BIT: Binary Digit. On/Off, 0/1, Magnetic/Not
• BYTE: Group of bits for one character
– EBCDIC- Extended Binary Coded Decimal
Interchange Code (8 bits per byte)
– ASCII- American Standard Code for
Information Exchange (7 or 8 bits per byte)
• PARITY BIT: extra bit added to each byte to
help detect errors
*
HOW CHARACTERS ARE STORED
IN COMPUTER MEMORY

24. EXAMPLES OF BYTES
C: 1100 0011 0 100 0011 1
A: 1100 0001 1 100 0001 0
T: 1110 0011 1 101 0100 1
Note how sum for each byte is an EVEN
number
*
EBCDIC ASCII
(assume even-parity system)

25. ALU & CONTROL UNIT
• ARITHMETIC- LOGIC UNIT: CPU
component performs logic and
arithmetic operations
• CONTROL UNIT: CPU component
controls, coordinates other parts of
computer system
*

26. COMPUTER FILES
• RECORD: Data about a transaction
arranged in a set of FIELDS, each
holding a datum
• FILE: A group of similar records, such
as accounts receivable or payroll
• DATABASE: The files of an
organization, an electronic library
*

27. COMPUTER FILES
• SEQUENTIAL ACCESS: A sequence of
files arranged in order, say
alphabetically. Usually stored on
magnetic tape or cartridge
• DIRECT ACCESS: Records stored on a
DIRECT ACCESS STORAGE DEVICE
(DASD). Can move directly to any
record
*

28. DIRECT ACCESS STORAGE DEVICE
• HARD DISK: Steel platter array for
large computer systems
• RAID: Redundant array of Inexpensive
Disks
• FLOPPY DISK: Removable disk for PC
*

29. DISK PACK STORAGE
• LARGE SYSTEMS
• RELIABLE STORAGE
• LARGE AMOUNTS OF DATA
• QUICK ACCESS & RETRIEVABLE
• TYPICAL: 11 2-SIDED DISKS
• CYLINDER: SAME TRACK ALL SURFACES
CYLINDER 10: TRACK 10 (TOP AND BOTTOM OF EACH DISK)
DISK 1
DISK 2
DISK 3
DISK 4
DISK 5
READ/WRITE
HEADS

30. THE STORED PROGRAM CONCEPT
• COMPUTER IS A BINARY SYSTEM
• PROGRAM: A set of instructions telling
the computer what to do
• INSTRUCTION: Individual step or
operation in a program
• MACHINE LANGUAGE: Translated
instruction understood by particular
model of computer
*

31. CONTROLLER
• LINK FOR INPUT/OUTPUT OR FILE
DEVICES: To CPU and memory of
large computer systems
• HIGHLY SPECIALIZED PROCESSOR:
Manages the operation of attached
devices to free the CPU from these
tasks
*

32. DATA CHANNEL
• SPECIALIZED INPUT/OUTPUT
PROCESSOR (A COMPUTER): Takes
over function of device communication
from the CPU
• CORRECTS FOR SPEED MISMATCH
BETWEEN SLOW PERIPHERAL
DEVICES AND VERY FAST CPU
*

33. SYMMETRIC MULTIPROCESSOR
• PROCESSORS (CPUs) ARE
IDENTICAL, WITH EACH
PROCESSOR OPERATING
INDEPENDENTLY OF THE OTHERS
• USED IN MOST MAINFRAMES AND
SOME MIDRANGE MACHINES
*

34. PARALLEL PROCESSOR
(PP)
• MULTIPLE CPUs INSTALLED AS PART
OF A SINGLE COMPUTER SYSTEM:
Gives separate piece of program to
each of the processors so that work on
the program can proceed in parallel on
the separate pieces
*

35. MASSIVELY PARALLEL
PROCESSOR (MPP)
PARALLEL PROCESSING COMPUTER WITH
MANY PARALLEL PROCESSORS:
• 32 OR MORE: Different CPUs capable of
performing different instructions at the same
time
• 1000 OR MORE: CPUs must all carry out the
same instruction at the same time
*

36. CHAPTER 2
Computer Systems