Computer Achitecture and org - Introduction , Study notes of Computer Architecture and Organization

Download Computer Achitecture and org - Introduction and more Study notes Computer Architecture and Organization in PDF only on Docsity! Computer Architecture and Organization Introduction Unit I- Fundamentals of computer Architecture • Introduction and Organization of von Neumann machine • Instruction formats • The fetch/execute cycle • Instruction decoding and execution • Registers and registers files • Instruction types and addressing modes • Subroutine call and return mechanisms • Programming in assembly language • I/O techniques and interrupts • Other design issues ABACUS 4th Century B.C. The abacus, a simple counting aid, may have been invented in Babylonia (now Iraq) in the fourth century B.C. This device allows users to make computations using a system of sliding beads arranged on a rack. BLAISE PASCAL (1623 - 1662)  In 1642, the French mathematician and philosopher Blaise Pascal invented a calculating device that would come to be called the "Adding Machine". CHARLES BABBAGE (1791 - 1871)  Born in 1791, Charles Babbage was an English mathematician and professor.  In 1822, he persuaded the British government to finance his design to build a machine that would calculate tables for logarithms. With Charles Babbage's creation of the "Analytical Engine", (1833) computers took the form of a general purpose machine. ENIAC 1946 TRANSISTOR 1948  In the laboratories of Bell Telephone, John Bardeen, Walter Brattain and William Shockley discovered the "transfer resistor"; later labelled the transistor. Advantages: increased reliability 1/13 size of vacuum tubes consumed 1/20 of the electricity of vacuum tubes were a fraction of the cost TRANSISTOR 1948  This tiny device had a huge impact on and extensive implications for modern computers. In 1956, the transistor won its creators the Noble Peace Prize for their invention. IBM (PC) 1981  To satisfy consumer appetites and to increase usability, IBM gave prototype IBM PCs to a number of major software companies. For the first time, small companies and individuals who never would have imagined owning a "personal" computer were now opened to the computer world. Computer Generations FIRST GENERATION (1945-1956)  First generation computers were characterized by the fact that operating instructions were made-to-order for the specific task for which the computer was to be used. Each computer had a different binary-coded program called a machine language that told it how to operate. This made the computer difficult to program and limited its versatility and speed. Other distinctive features of first generation computers were the use of vacuum tubes (responsible for their breathtaking size) and magnetic drums for data storage. SECOND GENERATION (1956-1963)  Throughout the early 1960's, there were a number of commercially successful second generation computers used in • business, •universities, and •government from companies such as Burroughs, Control Data, Honeywell, IBM, Sperry-Rand, and others. These second generation computers were also of solid state design, and contained transistors in place of vacuum tubes. THIRD GENERATION (1965-1971) Though transistors were clearly an improvement over the vacuum tube, they still generated a great deal of heat, which damaged the computer's sensitive internal parts.  The quartz rock eliminated this problem. Jack Kilby, an engineer with Texas Instruments, developed the integrated circuit (IC) in 1958. The IC combined three electronic components onto a small silicon disc, which was made from quartz. Scientists later managed to fit even more components on a single chip, called a semiconductor. As a result, computers became ever smaller as more components were squeezed onto the chip. Another third-generation development included the use of an operating system that allowed machines to run many different programs at once with a central program that monitored and coordinated the computer's memory. FOURTH GENERATION (1971-Present) In 1981, IBM introduced its personal computer (PC) for use in the home, office and schools. The 1980's saw an expansion in computer use in all three arenas as clones of the IBM PC made the personal computer even more affordable. The number of personal computers in use more than doubled from 2 million in 1981 to 5.5 million in 1982. FIFTH GENERATION (Future) Computers today have some attributes of fifth generation computers. For example, expert systems assist doctors in making diagnoses by applying the problem-solving steps a doctor might use in assessing a patient's needs.  It will take several more years of development before expert systems are in widespread use. Introduction (cont..) • What is computer Architecture? – Refers to those attributes of a system visible to a programmer or – those attributes that have a direct impact on the logical execution of the program. – Eg. For architectural attributes: • instruction set, • no. of bits used to represent the various data types( nos. and characters) • I/O mechanisms and techniques for addressing memory. • What is computer organization? – Refers to the operational units and their interconnections that realize the architectural specifications. – Organizational attributes include • those hardware details transparent to the programmer, such as – control signals; – interfaces between the computer and peripherals; and – the memory technology used Difference between computer Architecture and organization • architecture is like a blue print, it will have all the components mentioned and also how they are connected, where as organization is an implementation of that blue print, each vendor will have their own version of the organization, their own way of implementing the blue print. • Many computer manufactures offer a family of computer models, all with the same architecture but with differences in organization. • Consequently, the different models in the family have different price and performance characteristics. • Further more, a particular architecture may span for many years and encompasses a number of different computer models, its organization changing technology. Functional view ut crf chintea} mcd cae # Data t 1s ye ree = a Daatan ay storage | aN 7ipure 1.8 “& Punctional View of the Computer Structure • There are four main structural components: – Central processing unit (CPU): • controls the operation of the computer and performs its data processing functions; often simply referred to as processor – Main memory: • stores data – I/O: • Moves data between the computer and its external environment – System interconnection: • Some mechanism that provides for communication among CPU, main memory, and I/O Computer operations 1 LEZ. * Data movement * eg: keyboard to screen | Slovement | Computer operations (4) • Processing from storage to I/O • Eg: printing a bank statement Structure ¢ Structure- the computer COMPUTER * Storage + Processing Figure 130 The Computer Structure- top level Organization of Von Neumann machine • ENIAC – background (first generation computer) – Electronic Numerical Integrator And Computer – Designed and constructed under the supervision of Eckert and Mauchly at the University of Pennsylvania – The project was a response to US wartime needs during World war II. – The Army’s Ballistics Research Laboratory (BRL), an agency responsible for developing range and Trajectory tables for new weapons was having difficulty supplying these tables accurately and within a reasonable time frame. – Without these firing tables, the new weapons and artillery were useless to gunners. ENIAC – background( cont.. ) – The BRL employed more than 200 people who, using desktop calculators, solved the necessary ballistics equation. Preparation of the tables for a single weapon would take one person many hours, even days. – So Mauchly and Eckert proposed to build a general purpose computer using vacuum tubes. – In 1943, the work began on ENIAC – Finished 1946 • Too late for war effort – Used until 1955 ENIAC - details • Decimal (not binary) • 20 accumulators of 10 digits • Programmed manually by switches • 18,000 vacuum tubes • Weighing 30 tons • 15,000 square feet • When operating it consumed 140 kW power • 5,000 additions per second Structure of von Neumann machine/ structure of IAS computer Central Processing Unit (CPU) Logic Unit (CA) Program Control Unit (CC) Structure of von Neumann machine/ structure of IAS computer • Central Arithmetic part: (CA) C=CA+CC – To perform the elementary operations of arithmetic most frequently(+ - * /) • Central control: (CC) – Proper sequencing of operations • Total memory: (M) – Any device which is to carry out long and complicated sequences of operations must have a considerable memory • Input unit: (I) – The device must have organs to transfer information from R into its specific parts C and M. • Output unit: (O) – The device must have organs to transfer from its specific parts C and M into R. IAS Memory Formats 01 39 oo sign bit (a) Number word left instruction right instruction 0 5 20 28 39 opcode address opcode address (b) Instruction word Expanded structure of IAS computer • Set of registers (storage in CPU) – Memory Buffer Register (MBR) • Contains a word to be stored in memory or sent to the I/O unit, or it is used to receive a word from memory or from the I/O unit. – Memory Address Register (MAR) • Specifies the address in memory of the word to be written from or read into the MBR. – Instruction Register (IR) • Contains the 8 bit opcode instruction being executed. – Instruction Buffer Register (IBR) • Employed to hold temporarily the right hand instruction from a word in memory – Program Counter (PC) • Contains the address of the next instruction pair to be fetched from memory – Accumulator (AC) & Multiplier Quotient (MQ) • Employed to hold temporarily the right hand instruction from a word in memory. For eg. The result of multiplying two 40 bit numbers is an 80 bit number, the most significant 40 bits are stored in the AC and the least significant in the MQ. Partial Flowchart of IAS Operation IBR — MBR (20:39) IR — MER (0:7) MAR = MBR (8:19) TR + IBR (0:7) IR — IBR (20:27) MAR — (8:19) MAR + IBR (28:39) LT PCePC+1 Decode instruction in IR AC Mx Go to M(X, 0:19) IfAC > 0 then AC = AC +MiX) go to M(X, 0:19) Execution cycle ¥ MBR + M(MAR) PC + MAR MBR = MiMAR) AC + MBR AC +AC+MBR = contents of memory location whose address is X bits i through j End of lecture 1