Week1 (1).pdf

Introduction to Information Technology and Computer Organization Chapter 1 Information Technology Information Technology (IT) refers to the management and use of the information using computer-based tools. Information technology (IT) is the use of any computers, storage, networking a...

Introduction to Information Technology and Computer Organization Chapter 1 Information Technology Information Technology (IT) refers to the management and use of the information using computer-based tools. Information technology (IT) is the use of any computers, storage, networking and other physical devices, infrastructure and processes to create, process, store, secure and exchange all forms of electronic data. 3 Data vs Information Data is raw facts and figures. Data means information, facts, statistics, etc., gathered together for reference, storage, or analysis. Information is obtained after data is processed. Useful and meaningful for users. Example: a sequence of numbers “100, 150, 200” is just data. However, if you put it into context: “The sales of a product over the past three months were 100, 150, and 200 units,” it becomes information because it provides meaning and context Bits and Bytes A bit is a binary digit, the smallest increment of data on a computer. A bit can hold only one of two values: 0 or 1, corresponding to the electrical values of off or on, respectively. Because bits are so small, you rarely work with information one bit at a time. Bits are usually assembled into a group of eight to form a byte. A byte contains enough information to store a single ASCII character, like "h". Bits and Bytes So in computer jargon, the following units are used: Unit Equivalent 1 kilobyte (KB) 1,024 bytes 1 megabyte (MB) 1,048,576 bytes 1 gigabyte (GB) 1,073,741,824 bytes 1 terabyte (TB) 1,099,511,627,776 bytes 1 petabyte (PB) 1,125,899,906,842,624 bytes Essential Computer Hardware Processing devices Brains of the computer Carries out instructions from the program Manipulate the data Most computers have several processors Essential Computer Hardware Memory devices Stores data or programs Random Access Memory (RAM) Volatile Stores current data and programs More RAM results in a faster system Read Only Memory (ROM) Permanent storage of programs Holds the computer boot directions 9 Essential Computer Hardware Input and output devices Allows the user to interact Input devices accept data Keyboard, mouse Output devices deliver data Monitor, printer, speaker Some devices are input and output Touch screens Essential Computer Hardware Storage devices Hold data and programs permanently Magnetic storage Floppy and hard drive Uses a magnet to access data Optical storage CD and DVD drives Uses a laser to access data Software Runs The Machine Tells the computer what to do Reason people purchase computers Two types of Software System software Application software Application Software It is the software which turns the computer into a tool for doing some specific tasks. These are the programs, which cater to various needs of the users. Application software is written for every type of task, i.e. from word processing to collecting information on the worldwide web. Example: Microsoft Word etc. System Software: One main type of system software is the operating system that is required by the computer to function. System software integrates the computer hardware components, and also provides the tools to use the software components in the desired manner and for the day-to- day maintenance tasks like displaying the list of all the directories and files on the disk. Example: Windows OS, Utilities etc. 15 Basic Organization of a Computer System The basic organization of a computer system is the processing unit, memory unit, and input-output devices. 4 Basic Operations of a Computer There are four basic operations which a computer performs, irrespective of the program which is running on it. They are classified as: Input Processing Output and Storage Also called IPOS Cycle (“Input Processing Output Storage Cycle”) The four steps of the IPOS cycle may not necessarily appear in the same sequence as they are defined. Input: Computer accepts data from some source, such as a user or a program. This involves inserting or feeding data into the computer by means of an input device, like a keyboard. Processing: Some action is performed on the input provided by the user or a program. Some kind of processing is done in the computer to take out or transform data in some way. Output: Processing result is displayed on any output device. The result can be in the form of text, numbers, images, sound etc. The computer produces an output on a device, such as a printer or a monitor, that shows the result of the processing operations. Storage: Processing result is stored on a disk. The computer stores the result of processing operations for future use in some storage device, such as a hard disk or a floppy disk. Input Processing Output Storage  The processing unit controls all the functions of the computer system. It is the brain of the computer e.g. CPU. The memory unit consists of arithmetic unit and a logic unit. Central Processing Unit (CPU) Output Control Unit Input Arithmetic/Logical Unit Memory Unit Storage Central Processing Unit (CPU) A CPU is a brain of a computer. It is responsible for all functions and processes. The actual processing of the data is carried out in the CPU. The CPU stores the data and instructions in the primary memory of the computer, called the Random Access Memory (RAM) and processes them from this location. Central Processing Unit (CPU) The Arithmetic Logic Unit (ALU) and the Control Unit (CU) are the two subcomponents of the CPU. The ALU carries out the arithmetic and logical operations while the CU retrieves the information from the storage unit and interprets this information. The CPU also consists of circuitry devices called cache and registers. Arithmetic Logic Unit (ALU) Executes all arithmetic and logical operations. Arithmetic calculations like as addition, subtraction, multiplication and division. Logical operation like compare numbers, letters, or special characters. The data and instructions stored in the RAM are transferred to the ALU for processing. The ALU performs the logical and the arithmetic operations on the data and the results are temporarily stored in the RAM. After the processing, the final results are stored in the secondary memory, i.e., the storage unit, and are released through an output device. Control Unit (CU) Controls and co-ordinates computer components. Read the code for the next instruction to be executed. Increment the program counter so it points to the next instruction. Provide the necessary data to an ALU or register. If the instruction requires an ALU or specialized hardware to complete, CU instructs the hardware to perform the requested operation. It selects, interprets, and ensures the proper execution of the program instructions. Registers To speed up the Computer processor's work by enabling quick access to often-used values, it has a collection of Registers that are incredibly fast but only hold a small quantity of data. Computer registers are memory storing units that operate at high speed. It's a component of a computer's processor. It can hold any type of data, including a bit sequence or a single piece of data. Eight registers, a memory unit, and a control unit make up a basic computer. Types of Registers Most common registers in computer: 1. Accumulator (processor register) 2. Program Counter (stores address of instructions) 3. Address Register (stores memory addresses) 4. Data Register (general purpose register used for storing data during calculations) 5. Instruction Register (stores current instructions being executed) 6. Temporary Register (holds the temporary data) Characteristics of Registers 1. Small, storage locations within the CPU 2. Manipulated directly by the Control Unit 3. Wired for specific function 4. Size in bits or bytes (not MB like memory) 5. Can hold data, an address or an instruction 6. The more registers a CPU has available, the faster it can work Functions of Registers in Computer Architecture Data Storage: Registers are used for the temporary storage of data or instructions during the execution of the program. They are mainly used to store information for a small time so that the CPU can access it quickly. Data Processing: We can perform various logical and arithmetic operations with the help of a register and the data of these instructions is stored in the accumulator register. Addressing: Registers are used to store memory addresses they can store the address of the instruction or the data that the CPU wants to access either to read from or write to. Data Transfer: Registers are used to transfer data between CPU and memory. Some of them hold the data that is read from or written to memory. Control: We can control the order of execution of instructions as some register wills tore the current instruction and some will store the next instruction to be stored. Microprocessor A microprocessor is an integrated circuit (IC) which incorporates core functions of a computer's central processing unit (CPU). It is a programmable multipurpose silicon chip, clock driven, register based, accepts binary data as input and provides output after processing it as per the instructions stored in the memory. Microprocessor A microprocessor executes a collection of machine instructions that tell the processor what to do. Based on the instructions, a microprocessor does three basic things: Using its ALU (Arithmetic/Logic Unit), a microprocessor can perform mathematical operations like addition, subtraction, multiplication and division. A microprocessor can move data from one memory location to another. A microprocessor can make decisions and jump to a new set of instructions based on those decisions.