Connect With Computers

Difference between Compiler and Interpreter Do you ever hear about Compiler and Interpreter? These are the programs which translates the high level language into machine language. Let’s know more about these programs. Compiler A program that translates high level language program into machine language program is known as compiler. It checks all kinds of limits, ranges, errors etc. But its program execution time is more and occupies a larger part of the memory. It has low speed and low efficiency of memory utilization. If a compiler runs on a computer for which it produces the object code it is known as a self or resident compiler , If a compiler runs on a computer other than that for which it produces object code, it is known as a cross compiler . The compiler derives its name from the way it works, looking at the entire piece of source code and collecting and reorganizing the instructions. Compilers require some time before an executable program emerges. However, programs prod

CACHE Memory Cache memory is placed in between the CPU and the main memory. It is faster than the main memory. Hence access time is much less than that of the main memory. The access time of a cache memory is 15-25 nanoseconds (ns) whereas that of the main memory is 80 ns . One nanosecond =10 9   second. The cache memory stores the data and instructions which are to be immediately executed. It is used to reduce average access time for address, instructions or data which are normally stored on the main memory. Thus it increases the operating speed of the system. Cache memory is much costlier than the main memory. From economical considerations, the size of cache memory is usually smaller than that of the main memory. Sometime cache is used to store only instructions. One such type of cache is used in 68020 processor. It has 256 bytes instruction cache, which allows it to pre-fetch instructions from the main memory and store them in the cache during the period when the system bus woul

Virus  Virus stands for Vital Information Resources Under Seige. Virus is a harmful program written for destructive purpose. Different kinds of virus perform different kinds of activity. Some virus delete programs some virus replicate themselves and make their own copies. Viruses are program in such a way that they could enter in the computer without the knowledge of the user. How does a computer virus attack? Once a virus has successfully attached to a program, file, or document, the virus will lie dormant until circumstances cause the computer or device to execute its code. In order for a virus to infect your computer, you have to run the infected program, which in turn causes the virus code to be executed. This means that a virus can remain dormant on your computer, without showing major signs or symptoms. However, once the virus infects your computer, the virus can infect other computers on the same network. Stealing passwords or data, logging keystrokes, corrupting files, spamming

What is a CPU? CPU( Central Processing unit) It is the most important unit of the computer system. CPU is considered as the brain of computer. in human body, all major decisions are taken by the brain and all other parts of the body function as directed by the brain. Similar to the human brain, in computer system, all major calculations, manipulations and comparisons are made by the CPU. The CPU is also responsible for activating and controlling the operations performed by all other units of the computer system. Central Processing Unit The major parts of a CPU are: a) Arithmetic and Logical Unit (ALU) b)Control Unit (CU) c)Memory Unit (MU) Arithmetic Logic Unit(ALU)  It performs all the mathematical and logical operations.The data and instructions, stored in the primary memory, are transferred to ALU for processing. Results generated by the ALU is transferred to the primary memory. After completion of processing, the final results are sent to an output device. ALUs are designed to perf

Printer Printers are the output device which provide hard copy of the output. They print the data on the paper or any other medium.It is a hardware device. A document can be of any type such as a text file, image, or the combination of both. It accepts input command by users on a computer or on other devices to print the documents. For example, if you have to submit a project report at your college, you need to create a soft copy of your report and print it with the help of the printer. Types of Printers  Printers are classified on various basis like printing method, printing speed and quality etc. Generally there are two categories of printers. Impact printer Non impact printer Impact printers These printers use hammer technology to print the data.They strike or hit on the paper to print the data.  These printers are noisy yet popular. Impact printers have mechanical moving parts to conduct printing.  Following are the impact printers Daisy Wheel A  daisy wheel printe r  is an early t

Operating system An operating system is software that controls the internal activities of the computer hardware and provider user interface. Each and every activity of your computer is directly of indirectly controlled by the operating system.  An  operating system  or  OS  is a  software  installed on a computer's  hard drive  that enables the computer  hardware  to communicate and operate with the computer  software . Without a computer operating system, a computer and software programs would be useless.          Operating system Functions of Operating system An operating system performs the following functions Processor Management      Memory management Input and Output management File Management  Scheduling Security Management 1) Processor Management  The operating system assigns processors (if a computer has more more than one processor) to the different tasks that must be performed by the computer. Some popular example of Operating system are: DOS, Windows, UNIX, LINUX etc 2)

Memory Memory means the devices which are capable of storing data in computers. The data and instructions entered into the computer must be stored inside the computer before the actual processing can start. Similarly the results produced after processing must also be stored before they passed on to the output unit. The main memory of the computer is designed to cater to such needs. It provides space for storing data and instructions, space for storing intermediate results, and also space for the final results. Information in a computer is stored in the form of strings of 0s and 1s. Computers also provide the facility of dividing the main memory into words or bytes. A byte usually consist of 8 bits of information.There are two types of memory. 1) Primary Memory 2) Secondary Memory 1) Primary Memory Primary memory is also called main memory or internal memory.  The primary memory stores instructions. It is important to understand primary memory generally holds currently executing process

Software Software means the set of programs, these are intangible part of the computer system  so we cannot touch and see them to do any work on the computer we give instructions to it. the group of related programs makes a software. Without software we cannot utilize computer system. There are various kinds of software which perform different types of operations. System Software     System software are the software which are designed to operate, control and manage the computer system. System software has following parts. 1) Operating System       Operating system is the main and essential part of computer system. We operate the computer using the operating system. It works as an interface between the user and the computer system. It creates and environment for the computer. It is the first program that is loaded in the computer. It works as a platform where all  the application software runs. There are following types of operating system. Single use r:- These operating system allow on

Difference between Input and Output devices Input Device  Data and instructions are entered into a computer through input devices. An input device first converts desired input data and instructions into a suitable binary form (i.e., 0 & 1) and then feeds it into the CPU. The commonly used input device is the keyboard. A number of other input devices have been developed that do not require typing. These are  Mouse Joystick Trackball Light pen Graphic tablet Touch screen     The above listed devices permit the user to select an image on the computer screen by pointing to it. Therefore, these devices also called pointing devices.      Voice input  system have also been developed. A microphone is used as an input in such devices. In applications, where computers with vision are required, namely robots and compute based security system, computer use optical and semiconductor devices that are sensitive to light. Such input devices produce digital signals corresponding to images, pictures

  Difference between Hardware and Software     Hardware     All the physical components or machinery parts of the computer system are known as Hardware. Such physical components may be electronic, magnetic, mechanical or optical. These include microprocessors, integrated circuits (ICs), hard disks, floppy disks, optical disks, color monitor, keyboard, printer and plotter, etc. Hardware is the tangible part of any computer system so we can touch and see them.     Software     Software means the set of computer program  procedures and associated documentation related to the effective operation of a computer system. A sequence of instructions given to a computer to perform a particular task is called a software or a program. Software are intangible part of computer system so we cannot touch and see them to do any work on the computer we give instructions to it. The group of related instructions make a program and the collection of related programs make a software. Without software we ca

Generations of Computer First Generation (1940-1956) Vacuum Tubes The first computers used vacuum tubes for circuitry and magnetic drums for memory, and were often enormous, taking up entire rooms. 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. First generation computers relied on machine language, the lowest-level programming language understood by computers, to perform operations, and they could only solve one problem at a time. Input was based on punched cards and paper tape, and output was displayed on printouts. The UNIVAC and ENIAC computers are examples of first-generation computing devices. The UNIVAC was the first commercial computer delivered to a business client, the U.S. Census Bureau in 1951. Second Generation (1956-1963) Transistors Transistors replaced vacuum tubes and ushered in the second generation of computers. The transistor was invented in 1947 but did not