1's and 2's Complement

1's Complement: The 1's complement of a binary number is obtained by changing each 0 to a 1 and each 1 ta a 0, In other words, change each bit in the number to its complement. The process is shown below.

                         Find 1's Complement of 101011?
                                    Answer: 1-0
                                                0-1
                                                1-0
                                                0-1
                                                1-0
                                                1-0
                                                1-0

2's Complement: The 2's complement of a binary number is formed by taking the 1's complement of the number and adding 1 to the least significant bit position. The process is illustrated below.

                                Find 2's Complement of 101001?
                                                101001    
                                           +   010110
                                 Answer:    010111           

Boolean Algebra:  A division of mathematics which deals with operations on logical values. Boolean algebra traces its origins to an 1854 book by mathematician George Boole. The distinguishing factor of Boolean algebra is that it deals only with the study of binary variables. Most commonly Boolean variables are presented with the possible values of 1 ("true") or 0 ("false"). Variables can also have more complex interpretations, such as in set theory.

Computer tircks

Create a blog

Open Notepad

    On the very first line, type in "LOG" (without quotes) then press Enter for a new line
    Now you can type in some text if you want, then save the file.
  Next time when you open the file, notice its contents. Notepad automatically adds a time/date log every time you open the file. Text becomes unreadable
 

Open Notepad
    On the very first line, type in "don't eat the don't" (without quotes) then save and close the file. Note: the file should have only one line of the text above.Now, open the same file. You'll notice the text becomes unreadable squares. (try this with different text with the same format and length). 

Paint Secrets:

Create a trail image

    Open Paint, then open an image.
    Right-click on the image and select "Select All"
   Now hold the "Shift" key and move the image around. The image will be      drawn with trail. 10x Zoom

    Open Paint, then open a small image.
    Select the zoom "Magnifier" tool.
   Windows Paint lists out the zoom options from 1x to 8x, but there is a 10x...After selecting the Magnifier tool, point the mouse right at the border line right under "8x" and left-click. There you go.. the hidden 10x.

Other Secrets:
   Where is the relaxing music that you've heard during Windows XP  Installation?

 The file is in:
 C:\Windows\system32\oobe\images\title.wma
 

Game Secrets:

 Solitaire: Instant Win

 Press Alt + Shift + 2 to instantly win

Solitaire: Draw only 1 card (instead of 3)
Hold down Ctrl + Alt + Shift then click on unopened cards to draw.

FreeCell: Instant Win

Hold down Ctrl + Shift + F10 while playing, then click Abort.Now move one card.

Free Cell: Hidden Game Modes

    Go to "Game" menu choose "Select Game"
   Here you can choose from game mode 1 to 1,000,000. But -1 and -2 will also work (hidden modes)
 

Hearts: Show All Card

    Warning! this requires a modification on your registry. Be sure you follow the steps carefully. Damage your registry might damage your Windows.
    Open the "Registry Editor" by: "Start" >> "Run" then type "regedit" and press Enter
  Expand to HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Applets\Hearts
    

Right-click on the right panel and create a new String value with the name "ZB"
    Double-click to open this key "ZB" to edit its value. Then enter "42" and close the Registry Editor.
    Start Hearts and Press Ctrl + Alt + Shift + F12 to show all the cards

Minesweeper: 

Stop The Timer When you start to play a new game, the timer is ticking...
    Press Windows Key + D to show desktop.
    Now come back to the game by selecting it from the taskbar. The timer is stopped.

Pinball

    Unlimited Balls: Type bmax at a new game to get unlimited balls (no notification).
     Extra Balls: Type 1max at a new game to get extra balls.
     Gravity Well: Type gmax at a new game to activate Gravity Well.
   Promotion: Type rmax at a new game or while playing to get instant promotion and raising rank.
   Extra points with partial shots: Partially shot the ball just to pass the yellow light bars. There are 6 bars. With the first bar, you'll get 15,000 points, 2nd: 30,000,...
   Extra points with partial shots: Partially shot the ball just to pass the yellow light bars. There are 6 bars. With the first bar, you'll get 15,000 points, 2nd: 30,000,...
   Test Mode: Type hidden test with a new ball or new game. Now you can use your mouse to drag and move the ball where you want.

Applications Software Packages

Word Processing applications:The great advantage of word processing over using a typewriter is that you can make changes without retyping the entire document. If you make a typing mistake, you simply back up the cursor and correct your mistake. If you want to delete a paragraph, you simply remove it, without leaving a trace. It is equally easy to insert a word, sentence, or paragraph in the middle of a document. Word processors also make it easy to move sections of text from one place to another within a document, or between documents. When you have made all the changes you want, you can send the file to a printer to get a hard copy.Word processors vary considerably.


Spreadsheet applications: Spreadsheet applications (sometimes referred to simply as spreadsheets) are computer programs that let you create and manipulate spreadsheets electronically. In a spreadsheet application, each value sits in a cell. You can define what type of data is in each cell and how different cells depend on one another. The relationships between cells are called formulas, and the names of the cells are called labels.Once you have defined the cells and the formulas for linking them together, you can enter your data. You can then modify selected values to see how all the other values change accordingly. This enables you to study various what-if scenarios.
 
The Evolution of Language:Language first appeared between 30,000 and 100,000 years ago in the species Homo sapiens. But how did language evolve? Currently, there are two rival answers to this question: the first and more common explanation is that language was an adaptation of some sort; the second (chiefly espoused by Stephen Jay Gould) is that language is a spandrels, a non adaptive element arising as a byproduct of other processes. We will consider these explanations in reverse order.

 
operating system:An operating system is a layer of software which takes care of technical aspects of a computer's operation. It shields the user of the machine from the low-level details of the machine's operation and provides frequently needed facilities. There is no universal definition of what an operating system consists of. You can think of it as being the software which is already installed on a machine, before you add anything of your own. Normally the operating system has a number of key elements:
 

History Of The Computer

In its most basic form a computer is any device which aids humans in performing various kinds of computations or calculations. In that respect the earliest computer was the abacus, used to perform basic arithmetic operations.

Every computer supports some form of input, processing, and output. This is less obvious on a primitive device such as the abacus where input, output and processing are simply the act of moving the pebbles into new positions, seeing the changed positions, and counting. Regardless, this is what computing is all about, in a nutshell. We input information, the computer processes it

according to its basic logic or the program currently running, and outputs the results.

Modern computers do this electronically, which enables them to perform a vastly greater number of calculations or computations in less time. Despite the fact that we currently use computers to process images, sound, text and other non-numerical forms of data, all of it depends on nothing more than basic numerical calculations. Graphics, sound etc. are merely abstractions of the numbers being crunched within the machine; in digital computers these are the ones and zeros, representing electrical on and off states, and endless combinations of those. In other words every image, every sound, and every word have a corresponding binary code.

While abacus may have technically been the first computer most people today associate the word “computer” with electronic computers which were invented in the last century, and have evolved into modern computers we know of today.

The history of computing is longer than the history of computing hardware and modern computing technology and includes the history of methods intended for pen and paper or for chalk and slate, with or without the aid of tables. The timeline of computing presents a summary list of major developments in computing by date.

The first computers were people! That is, electronic computers (and the earlier mechanical computers) were given this name because they performed the work that had previously been assigned to people. "Computer" was originally a job title: it was used to describe those human beings (predominantly women) whose job it was to perform the repetitive calculations required to compute such things as navigational tables, tide charts, and planetary positions for astronomical almanacs. Imagine you had a job where hour after hour, day after day, you were to do nothing but compute multiplications. Boredom would quickly set in, leading to carelessness, leading to mistakes. And even on your best days you wouldn't be producing answers very fast. Therefore, inventors have been searching for hundreds of years for a way to mechanize (that is, find a mechanism that can perform) this task. 

                This picture shows what were known as "counting tables"

On The Role Of Computers in Everyday Life.

The computer is one of the most brilliant gifts of science. This device was originally developed by Charles Babbage. Most countries have developed fast due to computerization. Writing a program is essential for a computer. Speed, accuracy, reliability, and integrity are the main characteristics of a computer.

Many of the routine activities today at home and in business are done by computers. The computer has proved a friend and servant of science, technology and industry. Most offices, shops, factories and industries use computers. The Internet is a storehouse of information. The computer is a boon to all. Telecommunication and satellite imageries are computer based. Computers have made the world a global village today.

The computer is one of the most brilliant gifts of science. It is an electronic device for storing and analyzing information fed into it, for calculating, or for controlling machinery automatically. Charles Babbage developed this device first in 1812 followed by George Boole in 1854, Howard and Aitten in 1937, Dr. John Nouchly and J. P. Eckert in 1946. These computers were named the first generation equipment. Today, wit the 'Artificial Intelligence' technology, we are using fifth generation computers. Each new generation of computers has been smaller, lighter, speedier and more powerful than the earlier ones. Now note-book sized computers like laptop are fairly common. Computers have been dominating technology since 1970s, and has now entered almost all walks of life.

Writing a program is essential for running a computer. This job is done by a software engineer. A computer program is a complete list of instructions which the computer accepts in order to solve a problem. There are many different languages that can be used to programme a computer. BASIC, COBOL, FOR TRAN, C, C++, JAVA and Visual Basic are some of them.

Speed, accuracy, reliability and integrity are some of the characteristics of a computer. It can execute over a million instructions per second without committing and mistake. It can carry our calculations in just a few minutes that would require days if carried out manually. It helps us in solving many difficult problems of multiple calculations. Computer has a huge memory. It can hold large amount of data. The software technology has seen a spurt of development and firms like Microsoft have established themselves as market leaders, pioneering the IT revolution world over. It has provided us with efficiency and accuracy in our work. Software acts as the medium through which communication and dissemination of information are carried out.

In less than 50 years, computers have influenced practically every field of activity. Many of the routine activities today are being performed by computers. Use of computers has reduced the paperwork. Now most of the work is done directly on the computers. The traffic in large cities is controlled by computers. Automation in banks and railway stations have provided relief to the public and staff alike. Ticketing and reservation have become more efficient and convenient. Various types of games like chess and cards can also be played on computers.

In medical diagnosis, computers are being used to locate and investigate accurately and precisely abnormalities and diseases. Business transactions and high volume of associated data are easily managed by using computers.

Computer is the backbone of information technology whose major application lies in internet. Internet has some very useful applications in our day to day life.

One can get railway and air tickets booked online. This saves one from the trouble of standing in a queue for long hours. One can also apply for a job or admission in a school or a college by filling the application form online. This saves time and energy. One can also see results of any examination on the Internet. Tax returns can also be filed on the Internet. Income Tax form can be downloaded from the Income tax website.

The interconnection of computers worldwide, i.e., the internet, is revolutionizing the concept and the conduct of business. Visual and audio access to offices worldwide through the network has given rise to virtual offices. One can have easy access to information via internet. It is an ocean of knowledge for the students. It is a huge library. The Internet helps the student to study for the examinations. Students pursuing courses through distance education mode can study the subject online. The internet is the fastest and cheapest way to take admission in a foreign institution, collect geographical information of any region, chat with anybody in any corner of the world or search for life partner of one's choice.

The importance of the internet as an all-pervasive medium of the future has been well recognized in India. A very important indicator is the number of businessmen jumping on to internet related business. E-commerce is gaining popularity in India as it allows trade at low costs and offers enterprises a chance to enter the global market at the right time. E-commerce helps in various aspects of the business including identifying the customer, promoting sales and advertising, handling orders, taxes, shipping, payment processing, etc.

The state governments and the central government have put special emphasis on computer education in India. Computer application is also beig extended to legal arena. The Supreme Court of India has become the first court in the country to provide e-filing of cases.

Computerization has created a lot of jobs for DTP operators, Programmers, Hardware an Software professionals. It provides tremendous openings for new kinds of entrepreneurs.

The computer gives us many benefits. They can be used as typewriters. When equipped with telephone modems, with the help of computer we can chat across the world. Teleconferencing and video conferencing are also possible. The internet helps us to keep in touch with family and friends. One can get information about every subject known to man, ranging from government law and services. trade fairs, conferences, market information, education, society and politics.

The computer has proved as a friend and servant to science, technology and industry. The computer through Internet expands business opportunities. Computerization has been done in business, banking, electronic publishing, engineering, creative designing, fashion designing, etc. It is used in railways, airlines, defence service, research establishments. postal and communication departments, meteorology, medical science, stock-broking etc. In defence, they help radars, missile and rocket launching. They have opened new avenues of shopping and entertainment.

Telecommunication and satellite imagery are computer based. Computerization can play an important role in rural areas in seed research, crop disease management and software development for rural industries.

The computer also has its negative side. The rise of cyber crime, the use of chat rooms for indecent discussion, certain websites, which deal in pornographic material have been noticed. But the advantages and importance outweigh the disadvantages. Through computerization, the world has become a global village today.

Computer memory

 Computer memory:

This article includes a list of references, related reading or external links, but its sources remain unclear because it lacks inline citations. Please improve this article by introducing more precise citations. (June 2011)In computing, memory refers to the physical devices used to store programs (sequences of instructions) or data (e.g. program state information) on a temporary or permanent basis for use in a computer or other digital electronic device. The term primary memory is used for the information in physical systems which are fast (i.e. RAM), as a distinction from secondary memory, which are physical devices for program and data storage which are slow to access but offer higher memory capacity. Primary memory stored on secondary memory is called "virtual memory".

The term "storage" is often (but not always) used in separate computers of traditional secondary memory such as tape, magnetic disks and optical discs (CD-ROM and DVD-ROM). The term "memory" is often (but not always) associated with addressable semiconductor memory, i.e. integrated circuits consisting of silicon-based transistors, used for example as primary memory but also other purposes in computers and other digital electronic devices.

There are two main types of semiconductor memory: volatile and non-volatile. Examples of non-volatile memory are flash memory (sometimes used as secondary, sometimes primary computer memory) and ROM/ PROM/ EP ROM/ EEP ROM memory (used for firmware such as boot programs). Examples of volatile memory are primary memory (typically dynamic RAM, DRAM), and fast CPU cache memory (typically static RAM, S RAM, which is fast but energy-consuming and offer lower memory capacity per area unit than DRAM) .

Volatile memory:

Volatile memory is computer memory that requires power to maintain the stored information. Most modern semiconductor volatile memory is either Static RAM (see S RAM) or dynamic RAM (see DRAM). S RAM retains its contents as long as the power is connected and is easy to interface to but uses six transistors per bit. Dynamic RAM is more complicated to interface to and control and needs regular refresh cycles to prevent its contents being lost. However, DRAM uses only one transistor and a capacitor per bit, allowing it to reach much higher densities and, with more bits on a memory chip, be much cheaper per bit. S RAM is not worthwhile for desktop system memory, where DRAM dominates, but is used for their cache memories. S RAM is commonplace in small embedded systems, which might only need tens of kilobytes or less. Forthcoming volatile memory technologies that hope to replace or compete with S RAM and DRAM.

Non-volatile memory: 

Non-volatile memory is computer memory that can retain the stored information even when not powered. Examples of non-volatile memory include read-only memory (see ROM), flash memory, most types of magnetic computer storage devices (e.g. hard disks, floppy discs and magnetic tape), optical discs, and early computer storage methods such as paper tape and punched cards. Forthcoming non-volatile memory technologies include Fe RAM, CB RAM, PRAM, SO NOS, R RAM, Racetrack memory, N RAM and Millipede

Block Diagram Of Computer: 

A computer is designed using four basic units, they are:

1. Input Unit.

2. Central Processing Unit (CPU).    

     (a) Control Unit.    

     (b) Arithmetic and Logic Unit.

     (c) Registers.

 3. Memory Unit.

 4. Output Unit.

Input Device:Computers need to receive data and instruction in order to solve any problem. The Input Unit performs this operation. The input unit basically links the external world to the computer. The input unit consist of one or more input devices.Example:Keyboard, mouse.

Central Processing Unit (CPU):The CPU is known to be heart or brain of he computer system and the program to manipulate data into information.

Control unit: Control Unit refers to a functional unit which carries out four basic operations.

1.Fetches an instruction.

2.Decode the instruction.

3.Executes the instruction.

4.It stores the results.

Arithmetic Logic Unit: Arithmetic Logic Unit performs arithmetic and logic operations and controls the speed of these operations.Logic operations are like AND, OR, NOT.

arithmetic operations are like addition, subtraction, multiplication and division.

Register: Registers are high speed storage areas that temporarily store data during processing to enhance computer's performance.

Memory Unit: Memory Unit is an essential component of any digital computer, It is a storing device. It stores programs and data, which are required by the CPU, and the result after processing.

Output Devices:The output unit converts the data from binary form to the human understandable form before it displays the result.