Transcript Computer Fundamental - Kendriya Vidyalaya No 3, Jaipur

Chapter-1
Computer Fundamentals
By: Mr. Birbal Jat
PGT-Computer Sc.
KendriyaVidyalaya No 3 Jaipur
COMPUTER MEANS
C : Commonly
 O : Operator
 M : Machine
 P: Particular
 U: User
 T : Trade
 E : Education
 R: Research

The First in Computer World

World’s first electronic digital computer- ENIAC.
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India’s first built digital computer-SIDHARTH Made by ECI.
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India’s first built super computer-PARAM Made by C-DAC.
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First computer was established in main post office of Bangalore on 16 Aug 1986.

First computerized Post office – New Delhi.

PRADESH is computer language for Hindi Commands.

In 1971 census – IBM1401 computer was used in India.

Dr. Raj Reddy is the first Indian who get Ph.Ed. in computer Science.

SYSTMAIL is email service for Indian languages, provided by C-DAC.

MONTRA ONLINE- India’s first international internet service.

SIKKIM is the first state where telephone directly is available on internet.

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COMPUTER- AN INTRODUCTION

Computer is an electronic machine which calculates data very fast and
provides results accurately. It is considered that when we provide accurate
inputs in the computer, it provides 100% accurate outputs.
 COMPUTER SYSTEM: It is set of hardware and software devices which are
connected to each other to solve a specific problem.
DEVICES: Monitor, keyboard, Mouse, Printer etc.
 COMPUTER HARDWARE is a set of physical and magnetic devices which are
used to make computers. We can see and touch these peripherals.
Example: The outside border of a computer system.

COMPUTER SOFTWARE is a set of programs which are written in computer
languages i.e. machine, binary. These are used to work on computer
system. These provide instructions to various parts of a computer system.
Example: Windows 98.

COMPUTER FIRMWARE is a combinatin of S/w & H/w. Computer Chips that have
data recorded on them.
Example: iPod, Bluetooth, iBook

LIVEWAREi : is the term used for the people associated with and benefited from the computer
system. Example: getting feedback from users.
Characteristics of Computers
Advantages:
 Speed: Computers are much faster as compared to human beings. A
perform a task in a minute that may take days if performed manually.
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
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computer can
Accuracy : Computers can perform all the calculations and comparisons accurately.
High Storage: Computers can store a large amount of information in very small space.
Reliability: Computers are immune (unaffected) to tiredness and boredom (dullness) or
fatigue (weakness). Thus they are more reliable than human beings.

Versatility : Computers can perform repetitive jobs efficiently.They can work with different
types of data and information like graphic, audio, visual, characters etc.
Disadvantage:

Lack of Decision Making Power: Computers cannot decide on their own. They do
not have this power which is a great asset of human beings.

IQ Zero: Computers are dumb machines with zero IQ. They need to be told each and
every step.
EVOLUTION OF COMPUTER
Year
Device
Inventor
Description
3000 BC
ABACUS
China
The first mechanical calculating device in the history of
computer.
1600
Arabic math
China
(1234567890) numbers are began to used in
counting.
1614
Logarithm
John Napier
Used in calculating big numbers.
1642
Mechanical Calculator
or Pascaline
Blasé Pascal
Used o add two numbers
1673
Advanced Pascaline
Gottfried
Wilhelm
Used to perform addition, subtractions,
multiplication, division.
1801
Jacquard’s Loom
Joseph M.
Jacquard’s
Used to store information based on principle of
Punch cards.
1812
Differential Engine
Charles
Babbage
I/O unit, Calculation Unit, Memory Unit
1816
Analytical Engine
Charles
Babbage
Advanced version of Differential Engine. Now it
can do 60 additions in one minute.
NOTE: CHARLES BABBAGE IS CALLED FATHER OF COMPUTER BECAUSE HE WAS THE FIRST PERSON WHO IMAGINE ABOUT STORED PROGRAM CONCEPT.
EVOLUTION OF COMPUTER
Year
Device
Inventor
Description
1872
Calculator
Frank Boldwin
Used for normal calculation
1890
Electro Card
Herman Hollerith
Punch cards used in first electro Card Machine
1908
Parallel Punching
Machine
James Power
Used to store data
1910
Tabulator Machine
Herman Hollerith
Used in census of America
1942
Mechanical Analog
Computer
Venever Bush
Work on physical values as temperature,
Pressure, Current etc. instead of digits.
1944
Electrical Analog
Computer
Venever Bush
Used in chemical plants, petroleum refineries,
aircraft and electronic power plants.
1945
Digital Computer
Turing
The First digital Computer
1946
ENIAC
J.P. Eckert and John Mauchly
The first electronic digital Computer stands for
(Electronic Numerical Integrator and Calculator)
1947
EDVAC
Von Newman
It stands for (Electronic Discrete Variable
Automatic Computer). It stores instructions
alongwith data.
1948
EDSAC
Mauris Wilkes
It stands for ( Electronic Delay Storage
Automatic Calculator) . It calculates very fast.
Functional Components of Computer

Input Unit:
◦ It reads the data from the outside world.
◦ It converts these data in computer acceptable form.
◦ It supplies the converted data to the computer system for further processing.
◦ Computer uses input unit for data entry and instructions feeding purposes. Some of
the input devices are keyboard, mouse, MICR, OCR, OMR, Scanner, joystick ,
light pen, bar code reader etc.

CPU (Central Processing Unit):
◦ It consists of ALU (Arithmetic Logic Unit) , CU (Control Unit) and Memory Unit.
◦ It is also called the heart of the computer. It directs the operation of the I/O devices.

Output Unit:
◦ It accepts result produced by the computer.
◦ It converts these data in human acceptable form.
◦ It supplies the converted data to the outside world.
◦ The result given by the computer is called output . It can be obtained on output
devices like monitor, printer, plotter etc.
Computer Generations
Base
I Gen.
II Gen.
III Gen.
IV Gen.
V Gen.
Period
1947-58
1959-64
1965-75
1976-90
1991-2001
Electronic
Component
Vacuum Tubes
Transistor
Integrated
Circuits (IC)
LS -IC
VLS-IC
Access Time
Milliseconds
Microsecond (
Nanosecond
Nanosecond
Nanosecond
Memory
(Min.)
20 KB
128KB
1MB
16MB
256MB
Speed
300 IPS
300 IPS
1 MIPS
8 MIPS
100 MIPS
Languages
Machine
BASIC,COBOL
FORTRAN
C & C++, ADA
Java, dotNet
Storage
Device
Magnetic Drum
Magnetic Tape
Magnetic Core
Semiconductor
Optical
Examples
IBM 650
ENIAC
EDSAC, EDVAC
IBM 704
ICT 1300
IBM 360,1401
ICL 1900
IBM 3081
SPECTRA-70
CRAY-I
CRAY-IV
INTEL P I-IV
PARAM
Classification of Computers
On the Basis
of Purpose
• General
• Special
On the basis
of Application
• Analog
• Digital
• Hybrid
On the basis
of Size
•
•
•
•
Micro
Mini
Mainframe
Super
Note:
General computers are used for ordinary tasks like banking , pay-roll systems.
Special computers are used for specific task like space research, weather forecasting,
traffic control etc.
Analog computers work on physical values and transmits signal constantly.
Example – Petrol Pump where analog computer displays quantity & price of Petrol.
Digital Computers work only on binary digits and transmit signals discretely
(isolated).
Hybrid computer is combination of both analog & digital computers. These are
very costly and mainly used in hospitals to measures the BP/Temp/ other symptoms of
Patients.
Comparison of Computer based on Size
Types
RAM
(Min.)
HDD
(Min.)
Wordlength
Speed
(Min)
OS
Usage
Example
Micro
8-64 MB
10-100 GB
8-32 bit
100 MIPS
Windows
Home
Intel
Pentium
Mini
64-128MB
100200GB
32-64 bit
200MIPS
Windows,
Unix
Bank
IBM 6000
PDP-8
Main
Frame
128256MB
200-500
GB
64-128 bit
500 MIPS
Windows,
Linux
Railway
IBM 4300
HP 9000
Super
2561024MB
500-1000
GB
128-256 bit
1000 MIPS
Unix, Mac
Research
& aircraft
CRAY,
HITAC,
CYBER
205,
PARAM
PARAM was India’s first super computer built by C-DAC Pune in guidance of Dr.Vijay P.
Bhatnagar & Team.
PARAM 10000 is the latest version of PARAM which provides weather report of one
day within 01 minute and is the largest super computer of Asia.
PACE (Processor for Aerodynamic Computation and Evaluation)was another Indian super
computer produced by ANURAG (Advanced Numerical Research & Analysis Group)
Other Computer Types
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In recent years, design changes have reduced the size of micro
computers, making computer technology portable and affordable.
Laptop computers are roughly the size of a large notebook.
PC (Personal Computer) defines a computer designed for general use
by a single person.
Desktop : PC that is not designed for portability.
Palmtop: also known as PDAs (Personal Digital Assistants) that use
flash memory instead of a hard drive for storage.
Workstation: a desktop computer that has a more powerful processor
and additional memory, such as 3D graphics or game development.
Server: A computer that has been optimized to provide services to
other computers over a network.
Client: A computer that sends request for some information to the
Server over a network.
Wearable: The latest trend in computing is wearable computers, which
have applications like (e-mail, multimedia) etc.
Ex.- cell phones,
Computer Software
System Software
Operating System
Application Software
Word Processing
Utilities
Spreadsheets
Language Processor
DBMS
Assembler
Compiler
Graphics
Interpreter
Browsers
Operating System
OS is a set of programs that operates all activities of computer
system. An OS is prepared to increase the efficiency of computer
system. It is a link between user and hardware.
 Functions of Operating System:
◦ Memory Management: decides where and How files will be stored

in memory.
◦ Processor Management: Provides various tasks to CPU.
◦ I/O Management: Performs various I/O functions.
◦ File Management: Transfers and arranging of files.
◦ Communication: provides communication between user and Screen.
◦ Internal time Control: operates internal system clock.
Memory Management
The different types of policies & techniques for memory management are:
◦ Single Contiguous Allocation: it is the simplest allocation technique. But
has the poor usage of Processor and main memory.
◦ Partitioned Allocation: it allows more than one job in the main memory
at one time. But increases the complexity of the OS. It is the simplest
for supporting the multiprogramming.
◦ Paged Memory Allocation: In this each job is divided into pieces of the
same size, called pages. The physical memory is divided into pieces of
same size called blocks. Any page can be placed into any block. This
scheme eliminates fragmentation and increases memory and processor
utilization. But it slow down the processor and increases cost of system.
◦ Demand Paged Allocation: When a page is needed in main memory, the
page which are loaded on demand, are present on Hard Disk. This is
known as Demand Paged Allocation. It is beneficial when we have large
virtual memory and some times it makes processor overloaded.
Process Management
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We know that program is a set of instructions written in a programming language.
Process is a state of a program in execution. Or process is running program with
some specific tasks to do.
A program is a passive entity whereas a process is an active entity.
When OS creates and kills processes it is called Process Tree.
The life time of a process can be divided in to 5 states:
◦ New: The process has been created.
◦ Ready: The process is waiting to be allocated to a processor.
◦ Running : Instructions are being executed. When a process gets a control from CPU , it
starts executing.
◦ Suspended : A suspended process lacks some resource other than the CPU. Such processes
are normally not considered for execution until the related suspending conditions is fulfilled.
◦ Terminate: When the Process finally stops. A process terminates when it finishes executing
its last statement.
The OS groups all information that it needs about a particular process into a data
structure called PCB (Process Control Block)
 It contains Process No., Priority No., Process State and Program Counter.
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Process Scheduling
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Scheduling refers to a set of techniques supported by operating
system that controls the order in which the work to be done is
completed.
The main objective of scheduling is to increase CPU utilization and
performance.
We have to use some performance criteria to maximize the system
performance . These are:
◦ Throughput: it is measure of amount of work completed in a given time interval.
Higher throughput means better system performance. It can be calculated by
using the formula  The no of jobs completed / Total time to complete the jobs
◦ Time slice / Time Quantum : a small unit of time (in milliseconds) given to a
process by CPU.
◦ Turnaround Time: It is the delay between job submission and job completion.
◦ Waiting Time: It may be expressed as turnaround time, less than the actual
processing time.
Types of Scheduling

Non-Pre-emptive : In this Scheduling , Scheduled job always
completes before another scheduling decision is made. Therefore,
finishing order of the jobs is also same as their scheduling order.
The following Techniques use Non-Pre-emptive Scheduling:
◦ FCFS (First Come First Served)
◦ SJF (Shortest Job First) or SJN (Shortest Job Next)
◦ Deadline Scheduling

Pre-emptive Scheduling: In this a Scheduling decision can be made
even while the job is executing . It is more useful in high priority,
which requires immediate response. The following Techniques use
Pre-emptive Scheduling:
◦ Round Robin Scheduling
◦ Response Ratio Scheduling
Scheduling Techniques

FCFS(First Come First Serve): This is the simplest scheduling technique
which is managed by FIFO (First In First Out) queue. i.e. The Process which
requests the CPU first, is allocated the CPU First.
◦ The CPU executes the jobs in the ready queue one by one.
◦ Batch Processing is one obvious example of FCFS Technique in which all jobs in the batch
are executed one by one. But Turnaround time for the very first job in the batch is the best
and for the very last job it is worst.

SJF/SJN : In this technique, whenever a new job is to be admitted, the
shortest of the arrived jobs is selected and given the CPU time.
Throughput remains the same as in FCFS scheduling but waiting time
improves. SJN associates with each job the length of its next CPU burst.
(CPU burst is the CPU time required by a job to execute its continuous executable part.)

DEADLINE : In deadline scheduling the job with earliest deadline is
selected for scheduling. Deadline of a job is the time limit within which a
job must be over. If a job overshoots its deadline, it is said to be Deadline
over run. Deadline over run is calculated as K=C-D where K is Deadline
overrun ; C is job completion time and D is Deadline for a job.
Scheduling Techniques…

ROUND ROBIN : Round Robin (RR) Scheduling is aimed
at giving all programs equal opportunity to make progress.
This is implemented by ensuring that no program gets a
second opportunity to execute unless all other programs
have had at least one opportunity.
◦ A small unit of time, called a time quantum or time slice, is defined.
The ready queue (queue of programs waiting for CPU time )is treated
as a circular queue. The programs in the ready queue are processed
for the defined time slice, one by one.

RESPONSE RATIO : Response Ratio is calculated as follows
Response Ratio =Elapsed time / Execution time received
The job with highest response ratio is preferred over others.
When a short job arrives, its response ratio is high, it is
scheduled for execution immediately. A longer job would
achieve high enough ratio only after a subsequent wait.
TYPES OF OPERATING SYSTEMs

SINGLE USER: Single user operating system is a type of
operating system which allows only one user at a time.
◦ The most popular single user OS is MS DOS (Microsoft Disk Operating System).

MULTIPROCESSING : In this OS two or more independent
Processors are linked together in a coordinated system and the
instructions are executed simultaneously.
◦ It is used for major control applications like Rail , Road and Airways.

MULTIPROGRAMMING: In this OS more than one user
programs are executed at the same time. It increases the resource
utilization of CPU.
◦ It is used to support multiple interactive tasks simultaneously.
Some Popular Operating Systems:
MSDOS, UNIX,WINDOWS , LINUX. Mac, BOSS, Solaris…
TYPES OF OPERATING SYSTEMs

Time Sharing: This OS operates in an interactive mode with a
quick response time. The user sends a request and the OS
processes it and a response is displayed.

Real Time: In this OS the jobs have fixed deadlines and the jobs
have to be completed within their deadlines. It is used in Airlines
booking, Wholesale market and manufacturing to see the current
status.

Distributed : In this OS , the user can access remote resources in
same manner as they do local resources. Data and process
migration from one site to another is under the control of this OS.
◦ It is used for Resource Sharing, Load Sharing, Reliability and
Communications.

Network OS: it is used to support networking and servers. It
provides file sharing , print sharing, backup of data etc.
◦ Example : Windows NT server, Windows 9x, OS/2 and Macintosh
Internal Parts of Computer

Microprocessor: is a computer processor on a microchip made of
silicon metal. It is sometimes called a logic chip. Intel 4004 was the
first Microprocessor. It has four major components like:
◦ Control Unit : it controls all the functions like input , output ,
storage and process.
◦ Arithmetic Logic Unit: it is capable to perform addition
,subtraction, multiplication, division as well as comparisons.
◦ Register: it is a special temporary storage location within the
CPU. To execute an instruction , the CU retrieves it from main
memory and places it into a register.
◦ BUS: it refers to an electrical pathway through which bits are
transferred between the various computer components. Or we
can say a bus is a collection of wires over which the computer
sends information.
Internal Parts of Computer…

Clock Speed: it refers to the no. of pulses per second generated by
an oscillator (Alternator). Usually it is measured in MHz (Megahertz
pulses per second).

Processor: is the logic circuitry that responds to and processes the
basic instructions that drive a computer. These have 8 to 64 bit
word lengths. These are divided in two categories: RISC & CISC.
RISC
CISC
Reduced Instruction Set Computer
Complex Instruction Set Computer
All HLL support is done in Software
All HLL support is done in Hardware
Simple , Single-Cycle Instructions set
that perform only basic functions
Large and Varied instructions set that
perform simple and complex tasks
Direct execution control unit
A microcode control unit
Spend more transistors on registers
Spend fewer transistors on registers
Example:Apple, Mac G3, PowerPC
AMD, Cyrix and Intel
Internal Parts of Computer…

System Bus: it carries bits between CPU and only one
peripheral at a time. There are three main buses:
◦ Data Bus: it is an electrical path that carries 32 bits of data at
once between CPU and Memory and vice versa.
◦ Address Bus: it carries 32 bits memory address to read/ write
from Memory to CPU.
◦ Control Bus: it carries signals created by processor and other
devices.
 PCI ( Peripheral Component Interconnect) is a data bus standard developed by Intel
Corporation. It is a 64 bit bus with 66 MHz speed. We can add various devices
through it.
 EISA ( Extended Industry Standard Architecture) is also a data bus standard
developed by Compaq. It is a 32 bit bus and useful for multiprocessing and
multitasking. It is expensive but has better data transfer rate.
Various Registers:
Register
Functions
Accumulator
To store numbers and arithmetic calculations
Program
Counter
To store the address of the instructions which has to be
executed next.
Decoder
To decode and interpret the instructions given to computer
through input.
Memory
Address
Register (MAR)
To contain the address of a word currently required and to fetch
next instruction.
Memory Buffer
Register (MBR)
To store a word as it is read from memory and to place the
instructions in MAR.
Instruction
Register
To handle instruction and data at a speed about 10 times faster
than other registers and to generate the required signals.
INPUT DEVICES
Device-Name
Usage
Keyboard
The main input device that is used to enter data into computer. It
has 104 keys.
Mouse
A handheld pointing device that controls curser position on the
screen.
OCR
Optical Character Reader is a input device used to read
handwritten and printed documents.
OMR / ORS
Optical Mark Recognition is used to scan a printed form and
reads predefined positions of records. ORS (Optical Response Sheet)
MICR
Magnetic Ink Character Recognition is used to read special
symbols printed on a cheque in the banks.
Light Pen
It is used to draw lines or curve on the screen. Mostly used for
graphics works.
Joystick
Just like a mouse, mostly used for computer games
New Devices
Now a days, the following input devices are mostly used :- smart
card, bar code readers, Bio-metric sensors, Graphic Tablets and
scanners.
Output Devices
Device-Name
Usage
Monitor
The main output device which displays information on
screen. Also known as LCD,CRT, VDU , TFT, Monochrome. It
many adapters that decides the picture quality based on
resolution and pixels. SVGA (Super Visual Graphics
Adapter) with 640x480 (640 pixel and 480 rows), 256 colors
Printer
It prints an output on paper. Also known as hardcopy.
These are of two types: (i) impact (ii) Non-Impact.
Impact
The impact printers work like electronic typewriter in
which a key is pressed to take impress of Ink on Paper.
Example: DMP, Line Printer ,Drum Printer , Daisy Wheel etc.
Non-impact
While in a Non-impact there is no need of pressing key to
take impression of Ink. It use photo sensitive technology.
Example: Inkjet, Laser
Plotters
Used to print big pictures or maps of buildings, master
plans and to create 2-D/3-D graphs.
Memory

Introduction:

Types of Memory:

After CPU, memory is the most
important part. Memory is the place where data &
instructions are stored.
◦ Primary (Main) Memory
◦ Secondary (Auxiliary) Memory
◦ Cache Memory
Primary Memory is the internal part of computer. Data
& instructions are stored on electronic circuits. It is also
called semi-conductor memory. It can be of two types:
◦ RAM (Random Access Memory)
◦ ROM (Read Only Memory)
RAM v/s ROM
Random Access Memory
Read Only Memory
It is a temporary memory.
It is a permanent memory
We can read & write data in it.
Information can be only read in it.
It is a volatile memory because when
power is off, the data are lost.
It is Non-Volatile. So information
remains safe even when power is off.
Operating System is loaded in it at
booting time.
The information is written at the time of
manufacturing by the programmers
Transistors & capacitors are the main
part of RAM.
The user cannot change the programs
of ROM.
Data are kept in Row & Columns in it.
It is also used in automatic washing
machine & toys.
Static ,Dynamic, DDR are types of it.
PROM,EPROM,EEPROM are types of it.
Types of RAM

Static RAM: (SRAM)

◦ Data are transferred like
electronic current.
◦ Data are kept in microcapacitors.
◦ Refresh is essential otherwise
data will be destroyed after
sometime.
◦ Data are stored
permanently.
◦ Expensive but fast.
◦ Useful in multi-media.
◦ No need of refreshing.
◦ Used in cache memory & PC.

EDO RAM: (Extended Data Out)
◦ Advance form of DRAM
◦ Used in Pentium-I PCs
◦ Faster than DRAM.
Dynamic RAM: (DRAM)

SD RAM: (Synchronous DRAM)
◦ Faster than EDO RAM
◦ Used in Pentium-II & III PCs
◦ Increased access speed in MHz

RDRAM (Rambus DRAM): is the high speed memory but very expensive.

DDR RAM (Double Data Rate RAM): is the latest memory used in recent PCs.
Types of ROM
• PROM:
– Programmable ROM
– User can store
programs only once.
– User can make micro
code program can be
made that are
needed mostly.
– The process of
making program in
PROM is called
‘Burning’.
– Example: CD-R
• EPROM:
– Erasable PROM
– Information can be
removed by ultra
violet rays.
– Information can be
re-write after
removing previous
information.
– It is cheaper than
PROM because it is
re-useable.
– Example: CD(RW)

EEPROM:
◦ Electrically Erasable
PROM
◦ Information can be
removed by electric
signals.
◦ It is the simplest way
to store info in ROM.
◦ Now it is used to
store BIOS in
Memory.
◦ Example :Pen Drive
Cache Memory: is a semi-conductor (buffer)memory which lies between main
memory and processor. It is mainly used for increasing the speed of RAM.
Secondary Storage Devices
Devices
Usage
Magnetic Disk
It offers high storage capacity, reliability and the capacity to directly
access stored data.
Floppy Disk
These are quite cheap and allow to copy files from one computer to
another. Available in different size : 8-inch,5.25- inch and 3.5-inch. But have a
limited capacity.
Hard Disk
It is a disk storage device having very large capacity in GB with a
mechanism for reading & writing to the hard disk.
It is divided in to Tracks , Cylinders and Sectors.
Optical Disks
The following optical disks are available in markets which are mostly
used to store, record and play multimedia files.
CD-ROM (Compact Disk Read Only Memory)
DVD (Digital Versatile/Video Disk) ; Blue Ray Disk
WORM (Write Once Read Many) also called CD-R.
Zip Drive
It is a great replacement of Floppies. These are expensive and
come with USB interface. These are portable , fast and easy to use.
Pen Drive/Flash Memory It is a memory chip that is portable, fast and easy to use and. Also
known as removable disk. Mostly used for storing and transferring
data from one computer to another.
Bluetooth
It is a short range wireless technology used for connecting and
transferring data between two devices.
Various Ports of Computers
Ports
Usage
Serial Port
Generally, in a motherboard there are two serial ports. One serial port is for a
serial mouse and another is for external modem.
Parallel Port
It a connector through which a computer communicates with impact Printers.
Almost all motherboard provide one parallel port.
USB Port
Universal Serial Bus- is a bus standard becoming more common everyday.
Now-a-days almost devices are connected through these ports.
PS-2 Port
It is mostly used to connect keyboard, mouse, trackball and touch pad.
SCSI Port
It is a High Density 30- pin connector set on a motherboard, used to connect
external hard disk or a removable disk.
Infrared Port
It is a wireless technology used to connect a computer and a device to
communicate each other. For this a IR adapter and Software installation
required.
Example: Wireless Keyboard/mouse.
Terms used in Computers

Buffer: it is a temporary storage area. A buffer will take information from one
device and hold it until another device is ready to receive it.

Spooling: The collection of information from several sources at one point,
followed by orderly delivery of that information to the device. E.g. a printer .

Access Time: is the time from the start of one storage device access to the
time when the next access can be started.

Seek Time: is the time to position the head on a specific track on a fixed
head disks. It is the time taken by electronic circuit to select the required head.

Latency Time: The time required by a sector t reach below the R/W head.
On an average.

Heatsink: is a device that is attached to a microprocessor chip to keep it
from overheating by absorbing its heat and dissipating (dissolve) it into the air.
There are two types of heatsink.
(i)
Active heatsink that comes with a Fan.
(ii)
(ii) Passive heatsink that comes without fan.