CSIT123-week-3-lecture.pptx

University of Wollongong in Dubai Learning objectives 1. Distinguish between computer organization and computer architecture 2. Explain the structure and functions of a computer 3. Explain the hierarchycal structure of a simple single processor computer 4. Explain the hierarchical structur...

University of Wollongong in Dubai Learning objectives 1. Distinguish between computer organization and computer architecture 2. Explain the structure and functions of a computer 3. Explain the hierarchycal structure of a simple single processor computer 4. Explain the hierarchical structure of a multicore computer. 5. Explain the structures and the components of a motherboard 6. Explain the structure of the IAS or Von Neuman computer Computer architecture vs Computer organization Computer architecture 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 a program. A term that is often used interchangeably with computer architecture is instruction set architecture (ISA) Computer architecture vs Computer organization ISA or Instruction Set Architecture The ISA defines Instruction formats, instruction opcodes, Registers , Instruction and data memory; The effect of executed instructions on the registers and memory; and an algorithm for controlling instruction execution Computer architecture vs Computer organization Computer organization Computer organization refers to The operational units and their interconnections that realize the architectural specifications. Computer architecture vs Computer organization Examples of architectural attributes Architectural attributes include: The instruction set, The number of bits used to represent various data types (e.g., numbers, characters), I/O mechanisms, and techniques for addressing memory. Computer architecture vs Computer organization A distinguishing example It is an It is an architectural organizational design issue issue whether that instruction will be whether a implemented by a computer will special multiply unit have a or by a multiply mechanism that instruction. makes repeated use of the add unit of the system Computer architecture vs computer organization Why is it important? Many computer manufacturers Consequently, offer The different A family of models in the computer family models, Have different All with the same price architecture but with differences an performance in organization. characteristics. Computer architecture vs computer organization Why is it important? One more Reason A particular architecture may span many years and encompass a number of different computer models, its organization changing with changing technology.  Computer architecture vs computer organization The IBM 370- a very good example IBM System/370 The customer with modest architecture. requirements This architecture could buy a cheaper, was first slower model and, introduced in 1970 if demand increased, later upgrade to a more expensive, faster model without and included a having to abandon number of models. software that had already been developed. Computer architecture vs computer organization The IBM 370- a very good example These newer Over the years, models IBM has introduced Retained the many new models with same improved architecture so Technology to replace that older models, the customer’s Offering the customer software greater speed, lower investment was cost, or both. protected. Computer architecture and organization Structure and function A computer  is a complex system;  contains millions of elementary electronic components. Then  How, can we clearly describe them? The key is  To recognize the hierarchical nature of most complex systems Computer architecture and organization Structure and function A hierarchical system  Is a set of interrelated subsystems.  Each subsystem may, in turn, contain lower level subsystems.  until we reach some lowest level of elementary subsystem. The hierarchical nature of complex systems  Is essential to both their design and their description.  The designer need only deal with a particular level of the system at a time. At each level  The system consists of a set of components and their interrelationships.  The behavior at each level depends only on a simplified, abstracted characterization of the system at the next lower level. Computer architecture and organization At each level, the designer is concerned with structure and function: Structu Functio re: n: The The way in operation of which the each components individual are component as interrelated. part of the structure. Computer architecture and organization There are four basic functions that a computer can perform Data Data processing Storage Data Control movement Computer architecture and organization The function of data processing Data processing: Data may take a wide variety of forms, and the range of processing requirements is broad. However, there are only a few fundamental methods or types of data processing. Computer architecture and organization The function of data storage Data storage: Even if the computer is processing data on the fly (i.e., data come in and get processed, and the results go out immediately), the computer must temporarily store at least those pieces of data that are being worked on at any given moment. Computer architecture and organization The function of data storage Equally Thus, important, the computer performs a long- there is at least a term data storage short- term function. Files of data are stored on the computer data storage for subsequent function. retrieval and update. Computer architecture and organization The function of data movement Data movement: The computer’s operating environment consists of devices that serve as either sources or destinations of data. Computer architecture and organization The function of data movement When data are received from or delivered to a device that is directly connected to the computer, the process is known as input–output (I/O), and the device is referred to as a peripheral. Computer architecture and organization The function of data movement Data communications: it is the process when data are moved over longer distances, to or from a remote device. Computer architecture and organization The function of control Within the computer, a control unit manages the computer’s resources and orchestrates the performance of its functional parts in response to instructions Computer architecture and organization A hierarchical view of the internal structure of a traditional single- processor computer.: 4 main components Central processing unit (CPU):  Controls the operation of the computer  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 architecture and organization A hierarchical view of the internal structure of a traditional single- processor computer.: 4 main components A common example of system interconnection is by means of a system bus, consisting of a number of conducting wires to which all the other components attach. Computer architecture and organization Top level structure of a computer Four main structural components: Central processing unit (CPU): Main memory I/O System interconnection: (system bus) Computer architecture and organization Top level structure of a computer: the CPU main structural components Control unit:  Controls the operation of the CPU  and hence the computer. Arithmetic and logic unit (ALU):  Performs the computer’s data processing functions. Registers:  Provides storage internal to the CPU. CPU interconnection:  Some mechanism that provides for communication  among the control unit, ALU, and registers. Computer architecture and organization Another view of the organization of a simple computer with one CPU and two I/O devices The role of the registers:  The CPU contains a small, high-speed memory  used to store temporary results and certain control information.  This memory is made up of a number of registers,  Each having has a certain size and function. Computer architecture and organization Another view of the organization of a simple computer with one CPU and two I/O devices The registers how?  Usually, all the registers have the same size.  Each register can hold one number,  up to some maximum determined by its size.  Registers can be read and written at high speed since they are internal to the CPU. Computer architecture and organization A hierarchical view of the internal structure of a multicore computer Computer architecture and organization A hierarchical view of the internal structure of a multicore computer Multicore computers  Contemporary computers generally have multiple processors.  When these processors all reside on a single chip, the term multicore computer is used,  And each processing unit (consisting of a control unit, ALU, registers, and perhaps cache) is Computer architecture and organization A hierarchical view of the internal structure of a multicore computer- definitions Central processing unit (CPU):  The portion of a computer that fetches and executes instructions.  It consists of an ALU, a control unit, and registers.  In a system with a single processing unit, it is often simply referred to as a processor. Core:  An individual processing unit on a processor chip.  A core may be equivalent in functionality to a CPU on a single-CPU system.  Other specialized processing units, such as one optimized for vector and matrix operations, are also referred to as cores. Computer architecture and organization A hierarchical view of the internal structure of a multicore computer- definitions Processor:  A physical piece of silicon containing one or more cores.  The processor is the computer component that interprets and executes instructions.  If a processor contains multiple cores, it is referred to as a multicore processor Computer architecture and organization A hierarchical view of the internal structure of a multicore computer- definitions Cache memory:  a cache memory is smaller and faster than main memory  and is used to speed up memory access,  A greater performance improvement may be obtained by using multiple levels of cache,  with level 1 (L1) closest to the core  and additional levels (L2, L3, and so on) progressively farther from the core.  In this scheme, level n is smaller and faster than level n + 1. Computer architecture and organization A hierarchical view of the internal structure of a multicore computer- definitions Mother Board  Most computers, including embedded computers  in smartphones and tablets, plus personal computers, laptops, and workstations,  are housed on a motherboard. Printed Circuit Board (PCB)  It is a rigid, flat board that holds and interconnects chips and other electronic components.  It is made of layers, typically two to ten,  that interconnect components via copper pathways that are engraved into the board Computer architecture and organization A hierarchical view of the internal structure of a multicore computer- definitions Chips  The most prominent elements on the motherboard are the chips  It is a single piece of semiconducting material,  typically silicon, upon which electronic circuits and logic gates are fabricated.  The resulting product is referred to as an integrated circuit. Computer architecture and organization Structure of a core- its functional elements Instruction logic:  The tasks involved in fetching instructions, and decoding each instruction  to determine the instruction operation and  the memory locations of any operands. Arithmetic and logic unit (ALU):  Performs the operation specified by an instruction. Load/store logic:  Manages the transfer of data  to and from main memory via cache Computer architecture and organization Structure of a core- its functional elements Three Caches L1 L2 L3 Cach Cach Cach e e e Computer architecture and organization Structure of a core- its functional elements An instruction cache (I- cache) used for the transfer of instructions to and from main memory, L1 Cache And a L1 data cache, for the transfer of operands and results. Computer architecture and organization Structure of a core- its functional elements L2 Cache Today’s processor chips also include an L2 cache as part of the core. It is also split between instruction and data caches, although a combined, single L2 cache is also used Computer architecture and organization Structure of a core- its functional elements L3 Cache Used by Accessib Divided the le by all into two process the parts or cores  Computer architecture and organization The IAS computer or the von Neuman computer The first generation of computers used Then commercial vacuum tubes for computers were built digital logic elements using vacuum tubes. and memory. For our purposes, it will be instructive to examine perhaps the most famous first- generation computer, known as the IAS computer. IAS: Institute for Advanced Study Computer architecture and organization The IAS computer or the von Neuman computer A fundamental design In 1946, von Neumann approach first and his colleagues implemented in the IAS began the design of a computer is known as new stored- program the stored Program computer, referred to as concept, or the John the IAS computer, at the von Neumann Princeton Institute for computer Advanced Studies. Computer architecture and organization The IAS computer or the von Neuman computer The IAS computer, although not completed until 1952, is the prototype of all subsequent general- Purpose computers. Computer architecture and organization The components of the IAS computer A main memory, (M) An arithmetic and logic unit (ALU) A control unit, Input–output  Computer architecture and organization The structure of the IAS computer- the memory (M) The memory (M)  consists of 4,096 storage locations, called words,  of 40 binary digits (bits) each.  Both data and instructions are stored there. Numbers  are represented in binary form, Each instruction  is a binary code Computer architecture and organization The format of a number in the IAS Memory Each number  is represented by  a sign bit  and a 39-bit value. Computer architecture and organization The format of a word in the IAS Memory A word(Instruction) may alternatively contain  two 20-bit instructions, with each instruction consisting of  an 8-bit operation code (opcode) specifying the operation to be performed  and a 12-bit address designating one of the words in memory (numbered from 0 to 999). (which means the system only uses the first 1000 addresses) Computer architecture and organization The registers of the IAS computer The control unit and the ALU contain storage locations, called registers, MBR MAR IR IBR PC AC MQ Computer architecture and organization The MBR register of the IAS computer Memory buffer register (MBR): Contains a word to be stored in memory or sent to the I/O or isunit, used to receive a word from memory or from the I/O unit. Computer architecture and organization The MAR register of the IAS computer Memory address register (MAR): Specifies the address in memory of the word to be written from or read into the MBR. Computer architecture and organization The IR register of the IAS computer Instruction register (IR): Contains the 8-bit opcode instructio n being executed. Computer architecture and organization The IBR register of the IAS computer Instruction buffer register (IBR): Employed to hold temporarily the right- hand instruction from a word in memory. Computer architecture and organization The PC register of the IAS computer Program counter (PC): Contains the address of the next instruction pair to be fetched from memory. Computer architecture and organization The AC and MQ registers of the IAS computer Accumulator (AC) and multiplier quotient (MQ): Employed to hold temporaril y operands and results of ALU operations.  Computer architecture and organization The AC and MQ registers of the IAS computer- an example 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. Computer architecture and organization How does the IAS computer operate? The instruction cycle The IAS operates by repetitively performing an instruction cycle, Each instruction cycle consists of two subcycles. The fetch cycle The execute cycle Computer architecture and organization How does the IAS computer operate?- the fetch cycle During the fetch cycle,  the opcode of the next instruction is loaded into the IR  and the address portion is loaded into the MAR. (IR):  Contains the 8-bit opcode instruction being executed. (MAR):  Specifies the address in memory of the word to be written from or read into the Computer architecture and organization How does the IAS computer operate?- the fetch cycle This instruction may be taken from the IBR,  or it can be obtained from memory by loading a word into the MBR, and then down to the IBR, IR, and MAR. Computer architecture and organization How does the IAS computer operate?- the execute cycle Execution cycle:  once the opcode is loaded into the IR  the execute cycle is performed. Control Circuits interprets the opcode and executes the instruction  by sending out the appropriate control signals  to cause data to be moved  or an operation to be performed by the ALU.