Session 1-6.pdf

COMPUTER FUNDAMENTALS FUNCTIONALITIES OF A COMPUTER  Any digital computer carries out five functions in gross terms:  Takes data as input.  Stores the data/instructions in its memory and can use them when required.  Process the data and convert it into useful...

COMPUTER FUNDAMENTALS FUNCTIONALITIES OF A COMPUTER  Any digital computer carries out five functions in gross terms:  Takes data as input.  Stores the data/instructions in its memory and can use them when required.  Process the data and convert it into useful information.  Output the information.  Control all the above four steps DEFINITION  Computer System is an electronic data processing device which accepts and stores input data, processes the data input and output the processed data in the required format. ADVANTAGES  HIGH SPEED  ACCURACY  STORAGE CAPABILITY  DILIGENCE  VERSATILITY  RELIABILITY  AUTOMATION  REDUCTION IN PAPER WORK  REDUCTION IN COST DISADVANTAGES  NO I.Q  DEPENDENCY  ENVIRONMENT  NO FEELING APPLICATIONS  In every field  The computer's characteristic as high speed of calculation, diligence, accuracy, reliability, or versatility has made it an integrated part in all business organizations.  Computer used in business organization for:  Payroll Calculations  Budgeting  Sales Analysis  Financial forecasting  Managing employees database  Maintenance of stocks etc  The main features of First Generation are:  Vacuum tube technology  Unreliable  Supported Machine language only  Very costly  Generate lot of heat  Slow Input/output device  Huge size  Need of A.C.  Non portable  Consumed lot of electricity  Some computer of this generation were:  ENIAC, EDVAC, UNIVAC, IBM-701, IBM-650  The main features of Second Generation are:  Use of transistors  Reliable as compared to First generation computers  Smaller size as compared to First generation computers  Generate less heat as compared to First generation computers  Consumed less electricity as compared to First generation computers  Faster than first generation computers, Still very costly, A.C. needed, Support machine and assembly languages  IBM 1620, IBM 7094, CDC 1604, CDC 3600,UNIVAC 1108  The main features of third Generation are:  IC used  More reliable  Smaller size, Generate less heat, Faster  Lesser maintenance, Still costly, A.C needed, Consumed lesser electricity, Support high level language IBM-360 series Honeywell-6000 series PDP(Personal Data Processor) IBM-370/168 TDC-316  The main features of fourth Generation are:  VLSI technology used  Very cheap  Portable and reliable  Use of PC's  Very small size  Pipeline processing  No A.C. needed  Concept of internet was introduced  Great developments in the fields of networks  Computers became easily available  DEC 10, STAR 1000, PDP 11, CRAY-1(Super Computer), CRAY-X-MP(Super Computer)  The main features of fifth Generation are:  ULSI technology  Development of true artificial intelligence  Development of Natural language processing  Advancement in Parallel Processing  Advancement in Superconductor technology  More user friendly interfaces with multimedia features  Availability of very powerful and compact computers at cheaper rates  Some computer types of this generation are:  Desktop  Laptop  NoteBook  UltraBook  ChromeBook TYPES PC (PERSONAL COMPUTER)  A PC can be defined as a small, relatively inexpensive computer designed for an individual user.  PCs are based on the microprocessor technology that enables manufacturers to put an entire CPU on one chip.  Businesses use personal computers for word processing, accounting, desktop publishing, and for running spreadsheet and database management applications. WORKSTATION  Workstation is a computer used for engineering applications (CAD/CAM), desktop publishing, software development, and other such types of applications which require a moderate amount of computing power and relatively high quality graphics capabilities.  Workstations generally come with a large, high- resolution graphics screen, large amount of RAM, inbuilt network support, and a graphical user interface. MINICOMPUTER  It is a midsize computer. A minicomputer is a multi-processing system capable of supporting from up to 250 users simultaneously. MAINFRAME  Mainframe is a very large in size and is an expensive computer capable of supporting hundreds, or even thousands, of users simultaneously.  Mainframe executes many programs concurrently. Mainframes support many simultaneous programs execution. SUPERCOMPUTER  Supercomputers are one of the fastest computers currently available. Supercomputers are very expensive and are employed for specialized applications that require immense amounts of mathematical calculations (number crunching).  Weather forecasting , scientific simulations, (animated) graphics, fluid dynamic calculations, nuclear energy research, electronic design, and analysis of geological data (e.g. in petrochemical prospecting) COMPONENTS MEMORY  RAM- random access memory- are for primary storage, they are temporary storage areas for data and instructions, before and after processing by the CPU.  Volatile- contents lost when power goes off.  RAM is considered "random access" because you can access any memory cell directly if you know the row and column that intersect at that cell.  The opposite of RAM is serial access memory (SAM). SAM stores data as a series of memory cells that can only be accessed sequentially.  Dynamic RAM- DRAM- the capacitor in a dynamic RAM memory cell is like a leaky bucket. It needs to be refreshed periodically or it will discharge to 0.  SIMM- single inline memory module  DIMM- dual inline memory module  Static RAM uses a completely different technology. In static RAM, a form of flip-flop holds each bit of memory. A flip-flop for a memory cell takes four or six transistors along with some wiring, but never has to be refreshed.  Static RAM is fast and expensive, and dynamic RAM is less expensive and slower. So static RAM is used to create the CPU's speed-sensitive cache, while dynamic RAM forms the larger system RAM space. ROM  Read-Only Memory, ROM is a type of "built-in" memory that is capable of holding data and having that data read from the chip, but not written to. Unlike Random Access Memory (RAM), ROM is non- volatile which means it keeps its contents regardless if it has power or not.  ROM - Read Only Memory  PROM - Programmable Read Only Memory  EPROM - Erasable Programmable Read Only Memory  EEPROM - Electrically Erasable Programmable Read Only Memory CMOS  CMOS is short for Complementary Metal- Oxide Semiconductor.  CMOS is an on-board semiconductor chip powered by a CMOS battery inside computers that stores information such as the system time and date and the system hardware settings for your computer. CACHE  Because the CPU runs faster than the main system RAM, it ends up waiting for information. To reduce this cache is used, it temporarily stores instructions and data that the processor is likely to use frequently.  2 Kinds- Level 1 and level 2  L1- internal cache built into the processor chip.  L2- Resides outside the processor, SRAM chips.  L1 faster than L2  Capacity of L2 > L1 SECONDARY STORAGE Alternatively referred to as external memory and auxiliary storage, secondary storage is a storage medium that holds information until it is deleted or overwritten regardless if the computer has power. The Operating System The OS also called the software platform consists of the master system of programs that manage the basic operations of the computer. They handle the control and use of hardware resources, including disk space, memory, CPU time allocation and peripheral devices. The OS allows you to concentrate on your own tasks or applications rather than managing the computer. Different operating systems are usually incompatible.  What the OS does… Booting User Interface File Management Task Management Formatting Security Management  Booting Booting is the process of loading an operating system into a computers main memory. This is accomplished by programs stored permanently in the computers electronic circuits. When you turn on the machine, programs called diagnostic routines test the main memory, CPU and other parts to make sure they are working properly. BIOS programs are copied into main memory, which helps to interpret keyboard characters or to transmit characters to the screen or disk. Then the boot program obtains the OS usually from hard disk and loads into main memory. Cold and warm boots. Reboots can be either "cold" (alternatively known as "hard") where the power to the system is physically turned off and back on again, causing an initial boot of the machine, or warm (alternatively known as soft) where the system restarts without the need to interrupt the power. User Interface The first thing that you see after the computer finishes booting. It is a user controllable display screen which allows you to communicate or interact with the computer. The most popular is GUI with menus and icons. CPU Management The supervisor or kernel manages the CPU. It remains in main memory when computer is running. It directs other nonresident programs to perform tasks to support application programs. Partitioning- The OS divides memory into separate areas called partitions, each of which holds a program or data. Foreground/Background Queues/Spooling/Buffer  File management A file is a named collection of related information. A file can be a program or a data file. The OS records the storage location of all files. Formatting Formatting or initializing is the process of preparing the disk so that it can store data or programs. Task Management A task is an operation such as storing, printing or calculating. Security Management Operating systems allow users to control access to their computers by usernames and passwords. Especially important when several people use one computer or when on networks. Device Drivers and utilities Device drivers are specialized software programs that allow input and output devices to communicate with the computer. Utility programs or service programs performs tasks related to the control and allocation of computer resources. They enhance existing functions to provide services not provided by the OS. E.g. Anti virus, back up and recovery, compression, defrag.