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2. Bus Structures, Software, Performance.pptx
- 1. 20CS307- COMPUTER ARCHITECTURE UNIT– I BASIC STRUCTURE OF COMPUTERS Bus Structures, System Software
- 2. Contents… • Functional Units •Memory • Basic Operational Concepts • Bus Structures • System Software • Performance • Von Neumann Architecture • Harvard Architecture
- 3. Introduction Bus Structures Thereare many ways to connect different parts inside a computer together. A group of lines that servers as a connecting path for several devices is called a bus. Address Data Control
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- 5. Speed Issues • Differentdevices have different transfer / operate speed. • If the speed of bus is bounded by the slowest device connected to it, the efficiency will be very low. • How to solve this? • A common approach – use buffers.
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- 7. Hardware : Hardwareis a physical parts of the computer systems the parts we can touch and see. E.g Mother board, Keyboard, Monitor, Hard disk, Mouse etc. Software: Software is a collection of instructions that can be run on a computer. The instruction tell the computer what to do. Software is a bunch of code. System Software: 1. Operating System Software: Windows, Linux, Unix, DOS 2. Language Translator: It is another System Software which converts the high level language to machine understanding language. 3. Utility Software: Antivirus, File Management System, Disk Management tools, Compression tools, Disk cleanup tool. Control Unit: It is a component of a computers CPU that directs the operation of the processor.
- 8. Compiler: Compiler isa computer program that translates written in a high level language to lower level language ( Assembly Language to Machine Language). Interpreter: Program executes directly and it executes the program line by line. Assembler: Assembler is used to convert Assembly Language to Machine Code.
- 9. Performance • In eachfield, every one is attracted by the performance of that field. • When we choose among different computer, performance is an important attribute. Response Time: • Response Time is the time between the start and completion of the task is also referred as Execution Time
- 10. Defining Performance • ToMaximize the performance of computers we have to minimize the response time (or) execution time for some task 1 Performance R = …………………………………………. Execution Time R • This means that for two computers R & S, If the performance of R is greater than the performance of S. • Performance R > Performance S
- 11. • ie 11 ……………………… > …………………….. Execution Time R Execution Time S Execution Time S > Execution Time R • ie Execution Time on S is longer than the Execution Time on R, • If n times faster than S, that we can write, Performance R Execution Time S ………………………. = ………………………... = n Performance S Execution Time R E.g.: if a computer R runs a program in 15 seconds and computer S runs the same program in 30 seconds, how much faster is R than S? Performance R Execution Time S ………………………. = ………………………... = n Performance S Execution Time R 30 = ………. 15 = 2.0 So R is 2.0 times faster than S.
- 12. CPU Execution Time: CPU Execution Time is the time that CPU spends computing for particular task. User CPU Time : User CPU Time is the time spent in the os performing task on behalf of programs. CPU Clock Cycle for a program CPU Execution Time for a Program = ……………………………………………….. Clock Rate E.g: Computer A runs a program in 12 seconds with a 3 GHZ clock. We have to design a computer B such that it can run the same program in 9 seconds. • Determine the Clock rate of B • Assume that due to increase in clock rate, cpu design of computer B is affected and it requires 1.2 times as many clock cycle as computer A for execution this program. What clock rate should we tell the designer to target.
- 13. Clock Rate A= 3GHZ = 3 x10 Cycles / Second CPU Time A = 12 Seconds CPU Time B = 9 Seconds
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