Computer Basics

Computer Basics
Dr. D. P.
Mishra
Digitally signed by Dr. D. P. Mishra
DN: cn=Dr. D. P. Mishra, o=durg,
ou=BIT, email=dpmishra@bitdurg.
ac.in, c=IN
Date: 2023.07.23 18:50:49 +05'30'

Computer Generation
Unit-1
CCWT
:
Prof.
D.
P.
Mishra
BITD
2

Key for Computer Generations
• Time Frame
• Circuit Components
• Elements per Component
• Internal Storage
• Memory Capacity
• Data Input
• Popular Computers and Companies at that time
Unit-1
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Prof.
D.
P.
Mishra
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3

Zeroth Generation
• Man used his fingers, ropes, beads, bones, pebbles and other objects
for counting.
• Abacus, Pascaline, Difference & Anylitical engines
• Electricity was not yet invented
Unit-1
CCWT
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Prof.
D.
P.
Mishra
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First Generations 1951- 1958
• Vacuum Tubes
• Magnetic Drum
• 4,000 bits
• Hard Wire Programs in computers
• IBM 650, Univac I
• ENIAC
Unit-1
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Mishra
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Unit-1
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Prof.
D.
P.
Mishra
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First Generations 1951- 1958
• The first computers used vacuum tubes for circuitry and magnetic
drums for memory.
• They were often enormous and taking up entire room.
• First generation computers relied on machine language.
• . They were very expensive to operate and in addition to using a
great deal of electricity, generated a lot of heat, which was often the
cause of malfunctions.
• The UNIVAC and ENIAC computers are examples of first-generation
computing devices.
Unit-1
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Prof.
D.
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Mishra
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First generation computers
Unit-1
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Prof.
D.
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Pros / Advantages
• It was only electronic device
• First device to hold memory
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Mishra
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Cons / Disadvantages
• Too bulky i.e. large in size
• They generate more heat causing many
problems in temperature regulation and
climate control.
• Tubes were subject to frequent burn-out.
• They were producing heat
• Maintenance problems
Unit-1
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Prof.
D.
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Mishra
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Second Generation 1959-1964
• Transistors
• Magnetic Cores
• 32,000 bits
• Punch Cards
• CDC, GE, IBM
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• Transistors replaced vacuum tubes and ushered in the
second generation of computers.
• Second-generation computers moved from
cryptic binary machine language to symbolic.
• High-level programming languages were also being
developed at this time, such as early versions of COBOL
and FORTRAN.
• These were also the first computers that stored their
instructions in their memory.
Unit-1
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Prof.
D.
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Mishra
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• The Second Generation (1959 to 1964)
Unit-1
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D.
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Mishra
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Advantages :
• Size reduced considerably
• The very fast
• Very much reliable
Disadvantages :
• They over heated quickly
• Maintenance problems
Unit-1
CCWT
:
Prof.
D.
P.
Mishra
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14

Third Generation 1965-1974
• Silicon Chips (Integrated circuits)= IC
• Cores, IC’s
• 128,000 bits
• Keyboard Entry
• IBM, NCR, Honeywell
Unit-1
CCWT
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Prof.
D.
P.
Mishra
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Third Generation 1965-1974
• The development of the integrated circuit was the hallmark of the
third generation of computers.
• Transistors were miniaturized and placed on siliconchips, called
semiconductors.
• Instead of punched cards and printouts, users interacted with third
generation computers through keyboards
and monitors and interfaced with an operating system.
• Allowed the device to run many different applications at one time.
Unit-1
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D.
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Mishra
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Third generation computers
Unit-1
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D.
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Mishra
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Advantages
• RELIABILITY – Unlike vacuum tubes, silicon will not break down
easily. It is very seldom that you will have to replace it.
• LOW COST – Silicon chips are relatively cheap because of their
small size and availability in the market. It also consumes less
electricity.
Unit-1
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Prof.
D.
P.
Mishra
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Fourth Generation 1975-1989
• Silicon Chips (Large scale integrated circuits)=LSI
• IC’s, LSI’s
• 100 million bits
• Read programs off disks
• Apple, Xerox, Texas Instrument, Hewlett-Packard
Unit-1
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Mishra
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Fourth Generation 1975-1989
• These computers use microprocessor chips.
• Object-Oriented Programming (OOP) Languages such as Visual
Basic, and JAVA are characteristic of this computer generation.
Unit-1
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Prof.
D.
P.
Mishra
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21
Fifth Generation 1990-present
AI and NLP
Unit-1 CCWT : Prof. D. P. Mishra BITD

Unit-1
CCWT
:
Prof.
D.
P.
Mishra
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• Natural Language
• This language is designed to give people a more human connection
with computers.
• Uses multi-media has also defined this generation.
• There is a great deal of “bundled software” with this generation.

• Fifth generation computing devices, based on artificial intelligence.
• Are still in development, though there are some applications, such
as voice recognition.
• The use of parallel processing and superconductors is helping to
make artificial intelligence a reality.
• The goal of fifth-generation computing is to develop devices that
respond to natural language input and are capable of learning and
self-organization.
Unit-1
CCWT
:
Prof.
D.
P.
Mishra
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23

Optical Storage
It is a storage medium that can be written to and read using a laser beam.
Unit-1
CCWT
:
Prof.
D.
P.
Mishra
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24

Two Types of Optical Storage Devices
• CD-ROM (compact disk read-only memory)
• DVD-ROM (digital video disk read-only memory)

CD 12mm
120mm in diameter
1.2mm thickness

How Optical Storage Works
• An optical drive uses reflected light to read data.
• To store data, the disk's metal surface is covered with
tiny dents (pits) and flat spots (lands), which cause light
to be reflected differently.
• When an optical drive shines light into a pit, the light
cannot be reflected back.
• This represents a bit value of 0 (off).
• A land reflects light back to its source, representing a bit
value of 1 (on).

CD –ROMs
• Working principle:
Label
Protective acrylic
Polycarbonate plastic
Aluminum or other
metals
Laser beams
Land
Pit

Cross Section of CD-R
• .
Polycarbonate Substrate
Printed label
Protective lacquer
Reflective gold layer
1.2mm
Dye layer
Transmit beam
Reflective beam
Dark spot burned by laser

Optical Storage Devices – CD-ROM
• In PCs, the most commonly used optical storage
technology is called Compact Disk Read-Only Memory
(CD-ROM).
• A standard CD-ROM disk can store up to 700 MB of
data.
• Once data is written to a standard CD-ROM disk, the
data cannot be altered or overwritten.

Other Optical Storage Devices
• A CD-Recordable (CD-R) drive lets you record your
own CDs, but data cannot be overwritten once it is
recorded to the disk.
• A CD-Rewritable (CD-RW) drive lets you record a CD,
then write new data over the already recorded data.(100
times overwriting is possible)
• PhotoCD technology is used to store digital
photographs.

CD-ROM Speeds and Uses
• Early CD-ROM drives were called single speed, and
read data at a rate of 150 KBps.
• CD-ROM drives now can transfer data at speeds of up to
7800 KBps. Data transfer speeds are getting faster.
• CD-ROM is typically used to store software programs.
CDs can store audio and video data, as well as text and
program instructions.

Table 5.2 CD-ROM speeds
Speed
------------
1x
2x
4x
6x
8x
12x
16x
24x
32x
40x
Data Rate
------------------------
153,600 bytes per second
1,228,800 bytes per second
Approximation
------------
150 KB/s
300 KB/s
600 KB/s
900 KB/s
1.2 MB/s
1.8 MB/s
2.4 MB/s
3.6 MB/s
4.8 MB/s
6 MB/s

Digital Video Disk (DVD)
• A variation of CD-ROM is called Digital Video Disk
• DVD Read-Only Memory (DVD-ROM), and is being
used in place of CD-ROM in many newer PCs.
• Storage capacity ranges from 9.4 GB to 17 GB

DVD-ROM
• Standard DVD disks store up to 9.4 GB of data—enough
to store an entire movie.
• Dual-layer DVD disks can store up to 17 GB.
• Dual-layer DVD disks can store so much data because
both sides of the disk are used.
 Device’s laser beam can read data from the first layer and then
look through it to read from the second layer.

Recordable Optical Technologies
• DVD-Recordable (DVD-R)
 Record data onto a special recordable digital video disk using a special drive.
• DVD-RAM
 Record, erase, re-record data.

DVD
• The capacity improvement are due to 3 factors:
• 1. Smaller pits (0.4 microns versus 0.8 )
• 2. A tighter spiral (0.74 microns versus 1.6)
• 3. A red laser at 0.65 microns versus 0.78 microns.

Capacity of DVD
• 1. Single-sided, single-layer (4.7GB).
• 2. Single-sided, dual-layer (8.5GB).
• 3. Double-sided, single-layer (9.4GB).
• 4. Double-sided, dual-layer (17GB).

Newer Blue-Laser DVD
• There is a war between two new DVD standard right
now.
• One is SONY’s blue-ray system and the other is Toshiba’s
HD-DVD system.
• Nov 11, 2004 - Sharp Introduces Blu-ray Disc Recorder
with Hard Drive/DVD

Blue-Ray
• Digital dubbing between the hard drive, DVDs, and
Blu-ray Discs, including the ability to dub five DVDs
(4.7GB) onto a single Blu-ray Disc (25GB).
• The recorder also features an HDMI output jack,
enabling users to enjoy full-digital high-definition
video and high-fidelity audio with no signal
deterioration by outputting recorded high-definition
video (HDTV) to a compatible monitor for playback.
• The BD-HD100 will begin selling in Japan next
month for about 320,000 yen ($2,991).

42
Blu-ray Technology
• Name- Derived from the
blue-violet laser used to read
and write data.
 Developed by the Blu-ray Disc Association
with more than 180 members.
 Dell
 Sony
 LG

Blu-ray Technology Cont.
• Data capacity
 Because Blu-ray uses a blue laser(405 nanometers) instead of a red
laser(650 nanometers) this allows the data tracks on the disc to be very
compact.
 This allows for more than twice as small pits as on a DVD.
43

Blu-ray Formats
• BD-ROM (read-only) - for pre-recorded content
• BD-R (recordable) - for PC data storage
• BD-RW (rewritable) - for PC data storage
• BD-RE (rewritable) - for HDTV recording
• For More Details visit http://www.blu-ray.com/
44

Memory
• Main memory consists of a number of
storage locations, each of which is
identified by a unique address
• The ability of the CPU to identify each
location is known as its addressability
• Each location stores a word i.e. the
number of bits that can be processed by
the CPU in a single operation. Word
length may be typically 16, 24, 32 or as
many as 64 bits.
• A large word length improves system
performance, though may be less efficient
on occasions when the full word length is
not used
Unit-1 CCWT : Prof. D. P. Mishra BITD
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There are two types of main memory, Random Access Memory (RAM)
and Read Only Memory (ROM)
Random Access Memory (RAM)
holds its data as long as the computer is switched on
All data in RAM is lost when the computer is switched off
Described as being volatile
It is direct access as it can be both written to or read from in any order
Its purpose is to temporarily hold programs and data for processing. In
modern computers it also holds the operating system
Types of main memory

RAM ?
• Random-access memory (RAM) is a form of computer data
storage.
• Its in form of integrated circuits that allow stored data to be
accessed in any order in a constant time, regardless of its
physical location and whether it is related to the previous
piece of data.
• RAM is often associated with volatile types of memory
• The first RAM modules to come into the market were created
in 1951 and were sold until the late 1960s and early 1970s.

ROM ?
• ROM (Read Only Memory) is used to store the
instructions provided by the
• Manufacturer, which holds the instructions to
check basic hardware interconnector and
• To load operating system from appropriate
storage device

Types of RAM
1. Dynamic Random Access Memory (DRAM)
• Contents are constantly refreshed 1000 times per second
• Access time 60 – 70 nanoseconds
• Note: a nanosecond is one billionth of a second!
2. Synchronous Dynamic Random Access Memory (SDRAM)
• Quicker than DRAM
• Access time less than 60 nanoseconds
3. Direct Ram bus Dynamic Random Access Memory (DRDRAM)
• New type of RAM architecture
• Access time 20 times faster than DRAM
• More expensive

Types of RAM ..
4. Static Random Access Memory (SRAM)
• Doesn’t need refreshing
• Retains contents as long as power applied to the chip
• Access time around 10 nanoseconds
• Used for cache memory
• Also for date and time settings as powered by small battery
5. Cache memory
• Small amount of memory typically 256 or 512 kilobytes
• Temporary store for often used instructions
• Level 1 cache is built within the CPU (internal)
• Level 2 cache may be on chip or nearby (external)
• Faster for CPU to access than main memory

Unit-1
CCWT
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Prof.
D.
P.
Mishra
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Unit-1
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Prof.
D.
P.
Mishra
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Unit-1
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Unit-1
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D.
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Mishra
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1. Cache fetches data
from next to current
addresses in main
memory
2. CPU checks to see
whether the next
instruction it requires is in
cache
3. If it is, then the
instruction is fetched from
the cache – a very fast
position
4. If not, the CPU has to
fetch next instruction
from main memory - a
much slower process
Main
Memory
(DRAM)
CPU
Cache
Memory
(SRAM)
= Bus connections
Cache Memory

Memory Units
• The elementary unit of memory is a bit.
• A group of 4 bits is called a nibble and
• A group of 8 bits is called a byte.
• One byte is the minimum space required to store one character.
Other units of memory are:
• 1 KB (Kilo Byte) = 210 bytes = 1024 bytes
• 1 MB (Mega Byte) = 210 KB = 1024 KB
• 1 GB (Giga Byte) = 210 MB = 1024 MB
• 1 TB (Tera Byte) = 210 GB = 1024 GB
• 1 PB (Peta Byte) = 210 TB = 1024 TB

Question Appeared in ESE
Nov – Dec 2013
• What is Blue Ray Disk? – 2m
• List the parameters used to classify the computers. What major type of
computers are there based on this classification scheme? - 7M
• Explain the various functions performed by an operating System. – 7M
• What are the various Input/output units connected with computer System - 7M
Nov – Dec 2014
• Define primary memory. – 2m
• “Computer is an Electronic Device”, Justify. Explain various characteristics of
computer? - 7M
• Explain operating system and describe the features of operating system. – 7M
• Write short note on (i) CD-ROM, (ii) Blue Ray Disk - 7M
Unit-1
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Prof.
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Mishra
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April-May 2014
• What do you mean by algorithms?. – 2m
• Draw a block diagram to illustrate the basic organization of computer system and
explain the function of various components - 7M
• What is CDROM? In what way it is different from hard disk. Explain the process of
Reading and writing data in CDROM. – 7M
• Why is an operating system required for computer? Explain the following term (a)
Batch operating system , (ii) Multiprogramming operating system - 7M
Nov – Dec 2015
• Describe different computer languages primary memory. – 2m
• Describe various storage media and its use in detail? - 7M
• Write detailed note on generation of Computer. – 7M
• Describe various services of an operating system - 7M
Unit-1
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Prof.
D.
P.
Mishra
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Nov – Dec 2016
• Define OS. – 2m
• What are the various ways by which you can classify computers? Discuss each in brief. - 7M
• What do you mean by input unit? Draw and explain any five input devices. – 7M
• Discuss about the various storage media - 7M
April – May 2017
• What is system clock ? – 2m
• What are the various generations of computer? . - 7M
• What is operating system ? Explain various functions of operating system – 7M
• Write a short note on any three - 7M
Loader, Assembler, Blue ray Disk CD ROM
Unit-1
CCWT
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Prof.
D.
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Mishra
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Nov – Dec 2018
• What are the basic parts of computer. – 2m
• What are the main functions of operating system. - 7M
• How data is stored in CDROM, HD and Blue ray Disk ? . – 7M
• Give the example of machine, Assembly and high level languages
with proper code/set of instructions - 7M
Unit-1
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Prof.
D.
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Mishra
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What is system Clock ?
• In order to synchronize all of a computer's operations, a system
clock—a small quartz crystal located on the motherboard—is used.
• The system clock sends out a signal on a regular basis to all
other computer components
• In general, the clock refers to a microchip that regulates the timing and
speed of all computer functions.
• In the chip is a crystal that vibrates at a specific frequency when
electricity is applied.
• The shortest time any computer is capable of performing is one clock, or
one vibration of the clock chip.
• The speed of a computer processor is measured in clock speed, for
example, 1 MHz is one million cycles, or vibrations, a second. 2 GHz is
two billion cycles, or vibrations, a second.
Unit-1
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Prof.
D.
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Mishra
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Characteristic of System Clock
• The system clock is used to produce a specific pulse at a fixed rate of
time.
• The machine cycle of a system can be completed in a single or
multiple clock pulses.
• A single program instruction could be multiple instructions for the
cpu.
• The clock speeds are nowadays measures in Ghz. 1ghz = 1000 mhz.
Unit-1
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