RFID Reader

RFID means Radio Frequency Identification.

RFID reader is used to read RFD signals.

Generally we can say that RFID and barcode has same applications. They are used to store details of a particular thing or product.

RFID system consists of an antenna and a receiver, which reads Radio Frequency and transfer into processing device and the transponder or tag which is an integrated circuit containing Radio Frequency circuit and information to be transmitted. The details are stored in this IC.

Tags can carry information about,

•  Pet owner name and address
• Cleaning instructions on sweater
• Auto manufactures use RFID system to move cars through an assembly line.

Difference between RFID and Bar code

In RFID, line-of-sight contact is not needed for reading. While in Bar code, line-of-sight is must.
RFID can done scanning at a greater distance more than 90 feet.

Electronic Scabbing

Adapted from the slang term scab (a strike-breaker or one who crosses a strike line to work in place of striking employees).

Electronic scabbing refers to the practice used by managers and other executives when computer networks are used to transfer e-documents (e.g. accounting, clerical, word processing, database records etc.) to a non-striking work force.




Suppose a company has two branches, one in city A and other in city B. One day employees of B started a strike. Hence all the work in B is in pending. So the managers or other executives send the work through internet to branch A and the employees of that branch will complete the work. This practice is commonly known as electronic scabbing.

Number Systems

There are different types of number systems.
Normally we are using Decimal number system. ie, with base 10.
We all know that computer can understand only 0's and 1's. This number system is known as Binary number system. ie, base 2.

The main four number systems are given below,

1. Decimal: Base-10
                    Numbers are 0,1,2,3,4,5,6,7,8,9
                   
                    e.g. (935)10, (541)10, (12378)10 etc


2. Binary: Base- 2
                 Numbers are 0, 1

                 e.g.  (110)2, (1111)2, etc


3. Octal:  Base- 8
                Numbers are  0,1,2,3,4,5,6,7

                e.g. (745)8, (136)8


4. Hexadecimal:  Base- 16

Numbers used are:

Decimal                Hexadecimal

0                                 0
1                                 1
2                                 2
3                                 3
4                                 4
5                                 5
6                                 6
7                                 7
8                                 8
9                                 9
10                              A
11                              B
12                              C
13                              D
14                              E
15                              F

      e.g   (1A65)16, (ABCD)16 etc.

ASCII

We all know that computers can understand zeros(0's) and ones(1's) only.
But we are storing files with alphanumeric values and special characters, videos files, audio files etc in computer. Have you ever think about how this is possible ?

We can simply say that by converting into 0's and 1's. But how we can convert all these items into 0's and 1's ?

A method named ASCII is introduced for this purpose. ASCII means American Standard Code for Information Interchange.
ASCII is a 7 bit code. ie, 0-255 digits are there.

On storing any data in a computer, first of all, the computer will  convert that into ASCII. Then we can convert into 0's and 1's.

The ASCII table is given below. From that table, we can find out the ASCII equivalent of a particular character.

Multimedia

The term multimedia comes from two words muti and media.
Muti means many and media means doing some thing.

Multimedia is a combination of two or more from text, audio, video, graphics and animation.

Hypermedia is a combination of hypertext, audio and video.

Multimedia is categorized into two.


1. Linear Multimedia
  

• It is non iteractive
• Here, user has no cotrol over the content

        e.g. film, song etc.



2. Nonlinear Multimedia 

• It is interactive
• Here, user has control over the content

         e.g. games

Difference between assembler, compiler and interpreter

Assembler:

To convert assembly language into machine language.


Compiler:

A program that changes sorce code (high level language) into object code which can be executed by a machine.

Interpreter:

A computer program that executes instruction written in a programming language and do not produce the executable file.

Difference between compiler and interpreter

Compiler:

A program that changes source code (high level language) into object code which that can be executed by a machine.


Interpreter:

A computer program that  executes instructions written in a programing language and do not produce any executable file.

 

Difference between assemble and interpreter

Assembler:

To convert assembly language into machine language


Interpreter:

A computer program that executes instructions written in a language and do not produce any executable files.

Difference between assembler and compiler

Assembler:

To convert assembly language into machine language


Compiler:

A program that changes the source code (high level language) into object code which that can be executed by a machine.

Interpreter

 

A computer program that executes instructions written in a programming language and do not produce the executable file.

Interpreter:

• Checks the keyword of a program
• Taking one instruction at a time and convert it into machine language before taking upon the next instruction

Examples of interpreter base languages: PHP, JavaScript, BASIC

Compiler

A program that changes source code (high level language) to object code which that can be executed by a machine.

Compiler:

• Checks syntax of a program
• checks at a time all the program

Primary reason for compiling source code is to create an executable program

Examples of compiler based languages: C, C++, java

Executables: Files that actually do something by carrying out a set of instructions.


Some of the examples of compiler:

Microsoft Visual Studio
BlueJ
Quincy 2005

Assembler

Assembler is used to convert assembly language into machine code.

It translates mnemonic operation code to their machine language equivalents.

Assigning machine address to symbolic labels.

It can also process assembler directives.
Assembler directives provides introduction to the assembler itself. They are not translated into machine instructions

e.g: START : name and starting of string address for program.
     
       END : end of the source program and specify first executable instruction in the program.


Working of Assembler

• Programmer writes a program using sequence of assembly instructions.
• This sequence of assembly instructions, known as the source code/source program, then specified to the assembler program when that program is started.
• It translates a source code into machine language.
• The output of the assembler program is called the object program or object code.

Graphical User Interface (GUI)

GUI is a type of user interface that allows users to interact with electronic devices using images rather than text commands. GUIs can be used in computers, hand-held devices such as MP3 players, portable media players or gaming devices, household appliances, office, and industry equipment.

 

 

 

 

 

Menu Driven Interface

This interface requires the user to interact with the computer by selecting various options from a list of choices called a menu.

Advantages of menu-driven interface

• User does not need to memorise lots of commands
• Easy-to-use program for beginners with minimal training requirements

Disadvantages

• Certain operations/options cannot be ‘visual’
• Can be time consuming to find a command if unfamiliar with software

Nowadays, Graphical User Interfaces incorporate menus where commands are selected by pointing the mouse cursor at the command to be executed.

Command Line Interface

Command Line Interface is an interface in which, we have to give command for each and every step.
Here, we have to study all the needed commants for the running of each and every applications.
A program that implements such a text interface is often called a command-line interpreter, command processor or shell. The term 'shell', often used to describe a command-line interpreter, can be in principle any program that constitutes the user-interface, including fully graphically oriented ones—for example, the default Windows GUI is created by a shell program named EXPLORER.EXE, as defined in the SHELL=EXPLORER.EXE line in the WIN.INI configuration file.

CLI is manly used in 1970's and 80's.

 

 

The main disadvantage of CLI is that it is not user friendly.
We have to byheart all the commands.

The main advantage is that here, user is in direct contact with the system.

e.g :  MS-DOS, CP/M, Unix, and Apple DOS

Operating System

The interface between the user and the hardware is known as Operating System.
Operating Systm enables the communication between the user and the system.
Without operating system, we can't work with the system.

e.g: Windows NT, MSDOS, Linux, MacIntosh etc.


Features of OS :


1. Enables the communication between the user and the system.

2. Supervise the loading, storage and running of application softwares.

3. Control the working of input and output devices.

4. Memory management and allocation of memory.

5. Ensuring the system security.

6. Keep the system log.

 

 

 

 

 

 

Flash Drive

Flash Drives are commonly known as Pen Drives.
It uses the USB (Universal Serial Bus) port of computer for working.
It is an example for EEPROM. Bacause, the data contained in it is removed electrically.

A wide range of flash drives are available if we are considering the storage capacity. e.g. 4GB, 8GB, 16GB, 32 GB etc.

 

In market, a wide range of shapes or designs are also available.
Now flash drives with fancy designs are also availble in the market

In the shape of Sandwich

 

 

 

 

 

 

In the shape of car

 

 

 

 

 

 

 

                        In the shape of Guittar

 

 

 

Blue Ray Disc

Blue Ray Discs also works on optical technology.

 

The storage capacity of a blue ray disc is normally 100 GB.
The one reason for this high storage capacity is the tight packing of data.

 

 

 

 

 

Pcking of Data in CD, DVD and Blue Ray Disc

 

 

Blue ray discs uses the violet and blue rays of the spectrum. While Cds and DVDs uses red. Red ray has the highest wave length and so it need more space. So the storage capacity reduces.
Blue and violet rays belongs to low wave lenth group. So the storage capacity of the disc increases because the rays uses less space.

DVD

DVD means Digital Versatile Disc.
Some of us are calling it as Digital Video Disc. But its not the exact form.

DVD uses the same technology that of CD's.

The storage capcity of a DVD is normally 4.7 GB

In some DVD's, we can store data in its two surfaces.This is one of the reason for its high storage capacity.

There are mainly four different types of DVD's are available.

1.  Single Surface Single track DVD

2. Single Surface Double track DVD

3. Double Surface Single track DVD

4. Double Surface Double track DVD

CD

CD is the short form of Compactable Disc
It stores data digitally.
Laser beams used to read data from CDs

 

CD uses optical technology to store data in it.
The normal capacity of a CD is 750 MB

CDs are storing data as pits and humps. Pits reprasents lack of data and humps, presence of data.
Humps are used to reprasent 1's and pits for 0's.



CDROM:

It means Compactable Disc Read Only Memory.
Here, we can read the data from CD's. But we can't write into it.


CDRW:

Compactable Disc Read Write
Here, we can perform both read and write operations.

 

Magnetic Tape

Magnetic tape is a storage device.
Here, a strip is coated with some magnetic materials. And then it is putted on a plastic cover to protect from wear and tear.

When the tape comes near to read/write head, the magnetic material in the tape arranged in a particular shape.
At the time of reading, the shape of magnetic material is taken for consideration and the shape is checked with the prewritten shape.
Magnetic tape has a very high storage capacity.
In the same tape, different sectors are used to store data. Normally 6 tracks are there.

Floppy Disc

Floppy disc is an example for porttable memory device.
In floppy disc, a circular film is enclosed inside a plastic coating.

The memory capacity of a floppy disc is 1.44 MB

It has a write protected head, to protect from unwanted editings.
If the wite protected head is on, we can't perform writing into it.

 

 

 

The main advantage of this is portability.

Hard Disc

Hard disk is a secondary storage device.
The structure of a hard disc  several disks on a single spindle.
All the disks are put inside a metal cover.

All the disks have two surfaces.
Each surface is again devided into circular parts called tracks.
Each track is again devided into a set of sectors.
Each surface of a disc has its own read write head.

 

The size of hard discs are now in certain Terra Bytes (TB).

Difference between RAM and ROM

RAM :

RAM means Random Access Memory
We can perform both read and write.
It is volatile. That is, when power goes off , the contents of RAM will loose.
It is temporary storage device.
It is used to store data and programs to be processed.

ROM :

ROM means Read Only Memory
Writing into it is not possible
It is permanent storage device
It is nonvolatile
ROM is used to store boot programs. That is, the programs needed to run the operating system.

 

ROM

ROM means Read Only Memory.

ROM

It is used to store data permanently.
Here, we can't write data into it. The only thing we can do is just read data from it.
The data inside ROM will not loose when the power goes off, so it is nonvolatile

ROM is normally used to store the programs needed to run the operating system, known as boot program.

It is programmed at the time of manufacturing.

Different types of ROMs are,


1. ROM :

Read Only Memory

2. PROM

Programmable Read Only Memory.
We can write into this type of ROM. But, only once its possible.

3. EPROM

Erasable Programmable Read Only Memory.
Here, we can write the data as many times as we needed by erasing the previous.
To erase the data, we have to use ultraviolet radiation.

4.EEPROM

Electrical Erasable Read Only Memory.
Here, erasing is done with the help of electric signals. Its is much more flexible and this technology is widely using in nowadays .

RAM

RAM means Random Access Memory.

                                                                 RAM



It store the data and application programs before processing and just after processing.
RAM is volatile. That means when the power goes off, the content inside it will lose .
So we can say that RAM is a temporary storage device.

The data stored in RAM are the data and programs to be processed.

Primary Memory

Primary memory means it is inbuilt memory and it comes along with the computer.

Normally primary memory is attached beside the processor.
It holds the data to be processed and just after processed.
The size of primary memory is normally very less.
Primary memory is expensive.
It much more faster as compared to other memory devices.

Primary Memory is divided into two

1. RAM

2. ROM 

Memory

Memory means the area where the data after processing are stored.

After processing or before processing, we have to store the data in the computer. Because it it is not practical to give the same data always to the computer.
So we are using Memory for storing data.
The devices which stores the data are known as memory devices.

The memory is divided into two categories ,

1. Primary Memory

2. Secondary Memory

Printer

Printer is an output device.
They are used to get a printed copy of the document on a paper.

Mainly there are two types of printers .


1. Impact Printer:

In impact printers, there is a direct contact between the printing mechanism and the printer.
 It forms character images by staking a mechanism such as print hammer or wheel against an inked ribbon, leaving an image on the paper.

e.g.
       Drum printer, Dot matrix printer , Daisy-wheel printer, Line printer

                                                                     Dot-matrix Printer

                                                                Drum Printer

 

 

2. Nonimpact Printer:

Here, no direct physical contact between the print mechanism and page.

e.g. 
       Laser Printer: Creates images with dots

      Laser Printer

 

                                                                Working of Laser Printer

 

 

      
       Inkjet Printer: Spray small electric charged droplets of ink.

Inkjet Printer