Technologies and installation of computers Ali alhur

1. Technologies and installation of computers Ali alhur

2. Outline • Computer structure • Main components of hardware • 1. Input unit • 2. Central processing unit (CPU) • 3. Output unit • 4. Memory unit (internal memory) • 5. External storage

3. Computer structure • Computer system is made of two main parts: - • 1-(H/W) Hardware : refers to the physical equipment you see and touch when using computer system such as keyboard, memory, printer….etc. • 2-(S/W) Software: software is a collection of computer programs and related data that provides the instructions for telling a computer what to do and how to do it. Software refers to one or more computer programs and data held in the storage of the computer. Examples: Microsoftwindows is a software called operatingsystem نظام تشغيل , also programming languages like BASIC, PASCAL they all software.

4. Main components of hardware • The basic components of a computer system are: • 1. Input unit • 2. Central processing unit which consists of • Control unit • Arithmetic and logic unit • Register • 3. Output unit • 4. Memory unit (internal memory) • 5. External storage

5. Input unit • The input unit of a computer system accepts data, • convert it into electrical impulses that are sent in to internal memory or to the central processing unit (CPU) where can be processed. • Such as Punched cards (old system), Magnetic tape, Floppy disk, keyboard, mouse.

6. Central processing unit (CPU) • The brain of any computer system is the CPU, which is sometime called “Processor” معالج or “Microprocessor” in personal computer. • The CPU supervises and controls all of the peripheral equipment; perform arithmetic and makes logical decisions. • The CPU is responsible for includes the data movement computations and logical operation necessary to convert data into meaningful information.

7. Central processing unit (CPU) • Thus CPU performs two basic functions: • 1. The implementation of the program stored in the main memory according to the context of the program orders and instructions to adjust the equipment to perform the required functions. • 2. Mathematical and logical operations.

8. Central processing unit (CPU) • The CPU is a collection of recorders (Registers مسجلات ) which are used to store data entered into electronic circuits to perform calculations, • and is stored in the recorders is a temporary storage until the data processing • and transfer the results to the main memory • storage in the main memory is a storage deferred مؤجل long-term relatively it require data and contents of the address to be processed, • while storage in the CPU recorders is used for urgent الملحة او العاجلةcalculation only.

9. Central processing unit (CPU) • The Registers are directly controlled by the control unit CU that monitors data access to the registers • then the control unit give the commands to electronic computational and logical circuits to work • and then watching the movement storage of data in the other registers which are specified for output data, • sometimes input registers are used to keep the output of the calculations.

10. Central processing unit (CPU) • The CPU is divided into three sections: - • Arithmetic and Logic unit (ALU) • Control unit • Register

11. Central processing unit (CPU) • 2.1 Arithmetic and Logic unit (ALU) • Considered one of the most important components of the CPU where you perform all calculations and logical comparisons where this unit consists of a set of logic circuits. • Perform the processing of data including arithmetic operations such as addition, subtraction, multiplication, division and logic operations including comparison (ex. A<B) and sorting.

12. Central processing unit (CPU) • This unit has several components: • 1. Full addercircuitدائرة الجامع التام which makes the addition for 3 digits and half adder النصفيwhich add 2 digits. • 2. Reverse circuit العكسused for complement متممة the one or two of the binary number. • 3. Accumulator المركم , a bilateral group of cells called the register and is commonly used to hold the results of executing operations temporarily until transferred to memory or to other units. • 4. A group of cells showing the status of bilateral ثنائي process, this group of Registers called Status Register مسجلات الحالة or Flag Register.

13. Central processing unit (CPU) • ALU contain Register accumulator which is used to store the results of immediate calculations. • Accumulator can also carry out some calculations and logical operations, • ALU can receive data through accumulator or memory or CPU registers and receive control signal from the control unit where this signal specifies the type of operation to be performed in the ALU.

14. Central processing unit (CPU) • ALU also connected with the status register which stores a set of binary numbers that are used to control processes the data, the most important of these numbers are: • 1. Carry bit بت الحملwhere this bit contains one if there is a surplus فائضafter making the calculation. • 2. Zero bit بت الصفرwhere this bit contains one if the resulting value in accumulator equal to zero. • 3. Positive bit بت الاشارة الموجبةwhere contains one if the content of the accumulator is positive. • 4. Negative bit بت الاشارة السالبةwhere contains one if the content of the accumulator is negative.

15. Central processing unit (CPU) • 2.2 Control unit • The nervous العصبي system of a CPU, where the unit's controls all executed transactions • and monitor the execution sequence instructions , • coordinate ينسق operations , • exchange of information between the arithmetic , logic unit and the main memory.

16. Central processing unit (CPU) • The functions of this unit can be summarized to the following points: • 1. Instruction activation تنشيط to be performed and monitoring the transfer instruction from memory to the Instruction Register. • 2. Code analysis process تحليل شفرة العملية to determine the type of operation to be performed and send control signals for ALU. • 3. Activate of the data in memory locations and monitor مراقبة the transfer of such data to the CPU register. • 4. Inform اخبار او ابلاغ ALU which type of operation to be performed. • 5. Increase the program counter عداد البرنامج value equal to the length of the instruction to determine the address of the next instruction التعليمة اللاحقة in the main memory. • 6. Supervisionالاشراف of the passing تمريرresults to the main memory. • 7. Issue اصدار the necessary control signals to read or write from memory and control signals to ALU. • 8. Undertake يتولى the required time التوقيت المطلوب for the implementation of the above sequence.

17. Central processing unit (CPU) • Control Unit Components • 1. Address register: مسجل العنوان to store desired address memory location. • 2. Instruction register:مسجل التعليمة store the instruction to be performed. • 3. Program counter register: مسجل عداد البرنامج to store the address of the instruction to be performed later. • 4. Timing circuits: دوائرالتوقيتto achieve operational timing in the instruction sequence.

18. Central processing unit (CPU) • Control Unit Modes • The control unit is connected to several units and exchanges the information with these units; control unit may have one of the following modes: • Input mode: when control unit read the instructions and data from data bus ناقل البيانات. • Output mode: when CU send data over data bus. • Beginning new Operation mode. • Memory read mode. • Memory write mode. • Instruction fetch جلب او البحث عن تعليمةmode. • I/O read. • I/O write.

19. Central processing unit (CPU) • 2.3 Register • Register are devices capable of sorting information, • receiving data from other areas within the computer • and transferring information as directed by the control unit, • it is used for temporary storage of data or instruction. • Registers set or (recorders) are a very fast memory locations within the CPU used to generate and store the results of operations of the CPU, • also it is used for temporary storage of data or instruction and other calculations. • Computers Differ from each other by registers in terms of the number and types of registers and the length of each register and also differ in the use of all registers.

20. Central processing unit (CPU) • The most important registers are: - • 1-Program counter (PC): It contains the address of the next instruction to be executed. • 2-Instruction Register (IR): It contains the instruction being executed. • 3-Address Register (AR): holds the address of memory location. • Type of Registers: • 1. General purpose registers (GPR) الاغراض العامة: can be used for multiple purposes and assigned to variety of functions by programmer. • 2. Special purpose registers (SPR) الاغراض الخاصة : are restricted to only specific functions. In some cases. • 3. Data registers مسجلات البيانات DR: some registers are used only to hold data and cannot be used in the calculation of operand addresses. The length of data register must be long enough to hold values of most data types. Some machines allow two contiguous registers to hold double-length values. • 4. Address registers مسجلات العنوان AR : can be used for specific addressing or for general purpose addressing. • 5. Flag registers مسجلات الحالة : is used to hold processor status bits, or flag these bits are set by CPU as the result of the execution of an operation. The status bits can be tested later time as part of another operation.

22. Central processing unit (CPU) • Memory Access Registers: • Two registers are essential in memory write and read operation: • the memory data register (MDR) and memory address register (MAR), • The MDR and MAR are used exclusively بشكل خاص او حصريا by the CPU and are not directly accessible الوصول to programmers. • 1. Memory data register (MDR): this register will contain the data to be written into an address location. Sometimes this register is known as memory buffer register. • 2. Memory address register (MAR):this register is used to hold the address of the location to which the data is to be transferred.

23. Central processing unit (CPU) • In order to perform a write operation into specific memory location the MDR and MAR are used as follows: • 1. The word to be stored into the memory location is first loaded by the CPU into MDR. • 2. The address of the location into which the word is to be stored is loaded by the CPU into a MAR. • 3. A write signal is issued by the CPU.

24. Central processing unit (CPU) • Similarly, to perform a memory read operation, the MDR and MAR are used as follows: • 1. The address of the location from which the word is to be read is loaded into the MAR. • 2. A read signal is issued by the CPU. • 3. The required word will be loaded by the memory into MDR ready for use by the CPU.

25. Central processing unit (CPU) • Instruction Fetching Registers: مسجلات جلب او احضار الاوامر • Two main registers involved in fetching an instruction for executing are the program counter (PC) and the instruction register (IR) • Program Counter PC عداد البرنامج : The program counter is the register that contains the address of the next instruction عنوان التعليمة (او الامر) التالية to be fetched. • It holds the memory address of instruction currently being executed. • During the execution of the current instruction, the contents of the program counter register are updated to the address of the next instruction to be executed. • In the case of a branch operation العملية الفرعية , the program counter register is updated to point to the branch target instruction after the branch is resolved.

26. Central processing unit (CPU) • Instruction Register (IR) مسجل التعليمة او الامر : Is part of the control unit (CU) located within the central processing unit (CPU) • and stores the instruction to be executed or decoded. • IR is used to store the instruction being implemented in the microprocessor • also it receives this instruction which comes from the data buses and hold it temporarily until analyzed by microprocessor.

27. Central processing unit (CPU) • How CPU works: • The CPU is controlled يتحكم بها by a list of software instructions, called a computer programs , • software instruction entering the CPU originate in some form of memory storage device such as hard disk, floppy disk, CD-ROM …etc. • these instructions then pass تمرر into the computer’s main memory (RAM), where each instruction is given a unique منفرد address or memory location. • The CPU can access specific piece of data in RAM by specifying بتحديد the address of the data that it wants.

28. Central processing unit (CPU) • As a program is executed data flow from RAM through an interface unit of wires called the bus which connects the CPU to RAM. • The data then decoded by a processing unit called the instruction decoderthat implements software instructions. • From the instruction decoder the data pass the arithmetic logic unit (ALU), which performs calculations and comparisons. • Data may be stored by the ALU in temporary memory locations (in registers) where it may be retrieved quickly.

29. Central processing unit (CPU) • The ALU performs specific operations such as addition, multiplication, and conditional tests on the data in the registers, • sending the resulting data back to RAM or storing it in another register for further use. • During this process the program counter (PC) keeps track of each successive instruction to make sure that the program instructions are followed by the CPU in the correct order.

30. Central processing unit (CPU) • The Bus • A bus is a path between the components of computers. • There are two main buses in computer: the internal (or system) bus and the external (or expansion) bus. • The system bus resides the motherboard and connects the CPU to other devices that reside on the motherboard. • An expansion bus connects external devices, such as the keyboard, mouse, modem, printer, and so on, to the CPU. • Cables from disk drives and other internal devices are plugged into the bus. • The system bus has two parts: the data bus and the address bus.

31. Central processing unit (CPU) • The Data Bus • The data bus is an electronic path that connects the CPU, memory, and the other hardware devices on the motherboard. • The bus is a group of parallel wires. • The number of wires in the bus affects the speed, at which data can travel between hardware components, because each wire can transfer 1 bit of data at a time, an 8-wire bus can move 8 bits at a time. • A 16-bit bus can transfer 2 bytes, and a 32-bit bus can transfer 4 bytes at a time. • Newer model computers have a 64-bit data bus, which transfers 8 bytes at a time. • However, buses now are also being measured according to their data transfer rates the amount of data they can transfer in a seconds. • The performance of computer buses usually is measured in megabits per second (Mbps) or megabytes per second (Mbps).

32. Central processing unit (CPU) • The Address Bus • The Address Bus is a set of wires similar to the data bus. • The Address Bus connects only the CPU and RAM and carries only memory addresses. • Each byte in RAM is associated with a number, which is it memory address. • We have another type of bus is a Control bus to transmits control signals between different parts of the computer.

33. Central processing unit (CPU) • Clock Rate (Pulses) in the CPU: • Clock pulsesare a measure of the speed of a processor. • Clock pulses are measured in Hertz or number of pulses per second. • For instance, a 100-megahertz (100-MHz) processor has 100 million clock pulses passing through it per second, or gigahertz (GHz) processor has 100 billons of processing cycles per second. • Only old processor measured in MHz . • most of the new program can run on GHz processors such as AutoCAD MS office etc…, the faster processor is the more expensive.

34. Central processing unit (CPU) • Most CPUs handle two different kinds of numbers: • fixed-point and floating point numbers. • Fixed-point numbers unit have a specific number of digits on either side of the decimal point. • This restriction limits the range of values that are possible for these numbers, • but it also allows for the fastest arithmetic the fixed-point unit is used for two dimension programs like MS office.

35. Central processing unit (CPU) • Floating-pointnumbers unit are numbers that are expressed in scientific notation, • Scientific notation is a compact way of expressing very large or very small and allows a wide range of digits before and after decimal point. • This is important for representing graphics and scientific work like AutoCAD and games, • but floating-point arithmetic is more complex and can take longer time to complete. • Performing an operation on a floating-point number may require many CPU clock periods. • Some computers use a special floating point processor called Coprocessor. • Coprocessor works in parallel to the CPU to speed up calculations using floating-point numbers. • This coprocessor has become standard in many personal computer CPUs, such as Intel’s Pentium chip.

36. Central processing unit (CPU) • Machine Cycles: • Each time the CPU executes an instruction, it takes a series of steps. • The completed series of steps is called a machine cycle itself can be divided into parts: the instruction cycle and the execution cycle. • At the beginning of the machine cycle (that is, during the instruction cycle), the CPU takes two steps: • 1- Fetching: before the CPU can execute an instruction, the control unit must retrieve (or fetch) a command or data from the computer’s memory. • 2- Decoding: before a command can be executed, the control unit must break down (or decode) the command into instructions that correspond to those in the CPU’s instruction set.

37. Central processing unit (CPU) • At this point, the CPU is ready to begin the execution cycle: • 1- Executing: the CPU executes a command. • 2- Storing: the CPU may be required to store the results of an instruction in memory (but this condition is not always required). • Depending on the type of processor in use, a machine cycle may include other steps. • Although the process is complex, the computer can accomplish it an incredible speed, translating millions of instructions every second.

38. Central processing unit (CPU) • The CPU executes each Instruction in a series of steps: - • 1. Fetch the next instruction from memory to IR (instruction register). • 2. Changes the program counter to point to the following instruction. • 3. Determine the type of the instruction to be fetched. • 4. IF the instruction uses data in memory determines where they are. • 5. Fetch the data into the internal CPU register. • 6. Execute the instruction. • 7. Store the result in the proper place. • 8. Go to step 1 to being executing the following instruction.

39. Output unit • 3. Output unit • Output units are instruments ادوات of interpretation يفسر او يترجمand communication between human and computer, that let you see (or here) the result of the commands you enter, the most common output device are a display screen (monitor), printer or other device that let you see what the computer has accomplished ما اتمه الحاسوب.