Fundamentals of Computers and Operating System(OS)
- 1. 1. What is Computer:- A computer is an electronic device that manipulates information, or data. A computer can be programmed to carry out sequences of arithmetic or logical operations (computation) automatically. Modern digital electronic computers can perform generic sets of operations known as programs. These programs enable computers to perform a wide range of tasks. A computer system is a nominally complete computer that includes the hardware, operating system (main software), and peripheral equipment needed and used for full operation. This term may also refer to a group of computers that are linked and function together, such as a computer network or computer cluster. Page:-1
- 2. 2. What is Operating System:- The operating system is a system program that serves as an interface between the computing system and the end-user. Operating systems create an environment where the user can run any programs or communicate with software or applications in a comfortable and well- organized way. Furthermore, an operating is a software program that manages and controls the execution of application programs, software resources and computer hardware. It also helps manage the software/hardware resound, such as file management, memory management, input/output and many peripheral devices like a disk drive, printers, etc. These are the popular operating system: - Linux OS, Windows OS, Mac OS, VMS, and OS/400 etc. Functions of Operating System:- Processor management, Act as a Resource Manager, Memory Management, File Management, Security, Device Management, Coordinate with system software or hardware etc. Page:-2
- 3. 3. Fundamentals of Computer:- Page:-3
- 4. 4. Components of Computer System:- The Central Processing Unit (CPU):- Is the brain or the heart of a computer. Is also known as processor and consist of three units namely - 1. Control Unit ( C U) 2. Arithmetic logic Unit ( A L U) 3. Main Memory unit ( M M U) The system unit is the core of a computer system. Usually it's a rectangular box placed on or underneath your desk. Inside this box are many electronic components that process data. The most important of these components is the central processing unit (CPU), or microprocessor, which acts as the "brain" of your computer. Another component is random access memory (RAM), which temporarily stores information that the CPU uses while the computer is on. The information stored in RAM is erased when the computer is turned off. Almost every other part of your computer connects to the system unit using cables. The cables plug into specific ports (openings), typically on the back of the system unit. Hardware that is not part of the system unit is sometimes called a peripheral device. Peripheral devices can be external such as printer, monitor, external Zip drive or scanner or internal, such as a CD-ROM drive, CD-R drive or internal modem. Internal peripheral devices are often referred to as integrated peripherals. There are two types according to shape: tower and desktop. Page:-4
- 5. A motherboard (mainboard, system board, planar board or logic board) is the main printed circuit board found in computers and other expandable systems. It holds many of the crucial electronic components of the system, such as the central processing unit (CPU) and memory, and provides connectors for other peripherals. Generation of Computer: Generations Period Technology Used First Generation 1946-1959 Vacuum tube-based Second Generation 1959-1965 Transistor-based Third Generation 1965-1971 Integrated Circuit based Fourth Generation 1971-1980 VLSI microprocessor-based Fifth Generation 1980-onwards ULSI microprocessor-based Page:-5
- 6. Hardware. Software. Hardware is further divided into four main categories: Input Devices Output Devices Secondary Storage Devices Internal Components Software is further divided into two main categories: Application Software System Software Developed using electronic and other materials. Developed writing using instructions using a programming language. When damaged, it can be replaced with a new component. When damaged it can be installed once more using a backup copy. Hardware is physical in nature and hence one can touch and see hardware. The software cannot be physically touched but still can be used and seen. Hardware cannot be infected by Viruses. The software can be infected by Viruses. Hardware will physically wear out over time. Software does not wear out but it can be affected by bugs and glitches. An example of Hardware is hard drives, monitors, CPU, scanners, printers etc. An example of software is Windows 10, Adobe Photoshop, Google Chrome etc. Page:-6
- 7. 5. Input & Output Devices:- An input device is a computer device that allows computer users to enter data into a system and send instructions to the system to execute tasks accordingly. These devices are mainly hardware like keyboards, mouse, joysticks, etc. It is the first or primary step in the processing of computer data that is done at the Central Processing Unit (CPU). An output device is a computer device that displays the result of the inserted input data after getting processed from the CPU. CPU of a computer converts received information from machine language to a human-friendly language and then sends these signals to output devices to execute the tasks as per entered data. These output devices are mainly hardware like printers, monitors, speakers, etc. When the data entered by the input devices is processed by the CPU of the computer then the output devices show the result. Page:-7
- 8. 6. What is storage devices? Page:-8 The storage unit is a part of the computer system which is employed to store the information and instructions to be processed. A storage device is an integral part of the computer hardware which stores information/data to process the result of any computational work. Without a storage device, a computer would not be able to run or even boot up. Or in other words, we can say that a storage device is hardware that is used for storing, porting, or extracting data files. It can also store information/data both temporarily and permanently. Types of Computer Storage Devices: Now we will discuss different types of storage devices available in the market. These storage devices have their own specification and use. Some of the commonly used storage devices are: 1. Primary Storage Devices 2. Magnetic Storage Devices 3. Flash memory Devices 4. Optical Storage Devices 5. Cloud and Virtual Storage
- 9. Types of Computer Memory: Memory is primarily of three types − 1. Cache Memory 2. Primary Memory/Main Memory 3. Secondary Memory 4.Cache Memory: Cache memory is a very high speed semiconductor memory which can speed up the CPU. It acts as a buffer between the CPU and the main memory. It is used to hold those parts of data and program which are most frequently used by the CPU. The parts of data and programs are transferred from the disk to cache memory by the operating system, from where the CPU can access them. 5.Primary Memory: Primary memory holds only those data and instructions on which the computer is currently working. It has a limited capacity and data is lost when power is switched off. It is generally made up of semiconductor device. These memories are not as fast as registers. The data and instruction required to be processed resides in the main memory. It is divided into two subcategories RAM and ROM. Page:-9
- 10. 3. Secondary Memory: This type of memory is also known as external memory or non-volatile. It is slower than the main memory. These are used for storing data/information permanently. CPU directly does not access these memories, instead they are accessed via input-output routines. The contents of secondary memories are first transferred to the main memory, and then the CPU can access it. For example, disk, CD-ROM, DVD, etc. Page:-10