Introduction to Information Technology - Chapter 4 - Computer Hardware PDF

Introduction to Information Technology (401102) Chapter 4: Computer Hardware  2 IT Infrastructure There are three components that make up the Infrastructure of IT: Hardware: is applied to any of the physical equipme...

Introduction to Information Technology (401102) Chapter 4: Computer Hardware  2 IT Infrastructure There are three components that make up the Infrastructure of IT: Hardware: is applied to any of the physical equipment in a system. Not only the computer and devices such as screens and printers but also all the elements used to tie information systems together. Including: ▪ Input/output/memory/storage/processing units. ▪ Peripheral devices. ▪ Telephone wires, antennas and network cables. ▪ Any other electronic components. ▪ Any other communication devices. Software: the instructions that guide the hardware in the performance of its duties. Communications and networking.  3 Monitor Tower Headphones Mouse Microphone Speaker Keyboard Printer 4  5 Motherboard This is the main circuit board that all of the other internal components connect to. The CPU and memory are usually on the motherboard. Other systems may be found directly on the motherboard or connected to it through a secondary connection. For example, a Sound Card can be built into the motherboard or connected through PCI.  6 Computer Components Storage I/O CPU Memory  7 1 2 I/O Panel 1. Keyboard 8. Line in 3 4 2. Mouse 9. Mic 3. USB 10.Joystick 6 4. LAN 11.S-Video out 5 5. Serial 12.TV out 6. Parallel 13.VGA 7. Audio out 7 10 8 Two ways to think of I/O: 9 a) At the board/chip level (Physical Connections) b) What is connected to the board (User I/O’s) 11 12 13  8 Keyboards Standard Keyboard (considered as the Standard-Input-Unit): Most common device, the primary requirement is typing. ▪ Slow process. ▪ Intensive use may cause problems: “Repetitive Stress Injuries” (Carpal Tunnel Syndrome). ✓Solution #1: Split keyboards. Hands and wrist take proper placement while typing.  9 Keyboards ✓Solution #2: DataHand keyboards (by DataHand Systems, Phoenix, Arizona). Two unattached pads. The device has touch-sensitive finger-wells for the fingers and thumbs. Each finger-well allows 5 different commands (4 sides plus the bottom).  10 Keyboards ✓Solution #3: Ergonomic keyboards (the scientific analysis of man- machine interactions is called ergonomics) Different structures of keyboards have been designed to reduce physical stress injuries (e.g. Split and unattached two pieces on an arm-chair).  11 Keyboards ✓Solution #4: Virtual Keyboards / Soft or Touch- screen keyboards (tapping screen with your finger). Light Pen (Stylus) (tapping screen with alight pen).  12 Pointing Devices Pointing Devices used to move a pointer around on the screen to execute commands or to manipulate the data that has already been entered. Pointing devices include: ▪ Mouse (Point a cursor and click). Cordless mouse also exist. ▪ Trackball (Up-side-down mouse). ▪ Track Stick (Suitable for portable compact/notebook PCs) ▪ Joy Stick (Used for graphics and games). ▪ Touch Pad are flat rectangular pad sense the movement and pressure of your fingertip to control the mouse pointer. ▪ Graphics Tablet (Digitizer). You use a pencil-like stylus to execute commands and create drawings according to hand movement on the top of the pad.  13 Scanner Use Optical-Character-Recognition (OCR) software Like reversing the process of printing. Scanning converts text from a printed form back to an electronic form that you can edit and manipulate. The operation goes through several steps: 1) Scanned page converted to a picture called a bit-mapped- image. 2) OCR software analyze the light and dark areas on the page, making a guess at how the page is laid out. 3) OCR looks up for each character (template) in its library for matching a character on the page. 4) OCR uses a process called “Feature Extraction” to analyze chars. 5) Unclear characters appears in special symbols. 6) After conversion is complete, the page of text can be edited, modified, and then saved.  14 Bar codes and bar code scanner Bar code scanners are commonly found in retail stores. They scan the black and white bar code lines typically printed on labels on merchandise. In addition, they are very popular for tracking inventory items (e.g. Library books).  15 Bar Codes Made up of bars of different width and spacing that convey alphabetic and numeric information (usually about products or addresses) Universal Product Code (UPC ) consists of 11-digits [known as EAN outside the US and Canada].  16 POSTNET Point-of-Sale (POS) Terminals, are computerized cash registers incorporate bar cod scanners to input product code for pricing and other numerous data.  17 Optical Mark Reader Is a special scanner for detecting the presence of pencil marks on a predetermined grid, such as multiple-choice test answer sheets. (e.g. Marking the TOEFL exam papers in the past before they become on-line examinations).  18 Magnetic Ink Character Reader (MICR) Mostly, is used in the banking industry. Information is printed on checks in magnetic ink that can be read by the MICR technology. When characters magnetized they release signal that identify the characters. In banks, since a long time, checks are fed through Reader/Sorter Machines that can read, sort and route checks with speed of 2,400 checks per minute. Greatly increase the efficiency of handling checks.  19 Sensors Sensors, usually embedded in other technologies, collects data directly from the environment and inputs them into a computer. ▪ Examples: ▪ Car air bag activation sensor. ▪ Fuel mixture/pollution control sensor. ▪ Countless numbers/types of sensors built into a modern aircraft.  20 Cameras Digital Camera can capture images using the receptors called Charge-Coupled- Devices (CCD) instead of film. The images are stored on memory in the camera for later transfer to a computer, and then used in a document or printed. Digital Video Camera can be hooked up to a computer to feed images to the screen and to the hard disk. Film scanner/Recorder is used to digitize slide film & negatives. ❖Application: ▪ Virtual Reality gives you the feeling that you are experiencing a different space than the one you actually occupy.[hear, see & feel] E.g. Flight simulator used to train pilots. ▪ Hologram (provides a realistic 3-D vision) you may view a car model from different angles.  21 Speech Recognition Devices/Voice Recognition Devices Used in conjunction with microphones to input speech in to computers. Voice Recognition software (VRS) attempts to identify spoken words and translates them in to digital text. VRS requires training to become accustomed to the users voice and accent (the way you pronounce each word). Most commonly, voice systems work only for a single person, they are speaker –dependent. You first train the computer to become familiar with your accent to pronounce each word.  22 Storage Used by the computer to store programs, information, data (Write). Used by the computer to access information and programs when necessary (Read). Some storage can do both read and write, some only one. Some storage can randomly access information, some can only sequentially access. Magnetic ▪ Hard disk, floppy disk, ZIP disk, tape. Optical ▪ CD, DVD. Solid State ▪ Flash cards, PCMCIA cards.  23 Memory and Storage in Computers Definition: Memory is the functional unit of a computer that stores and retrieves information. ❖The amount and type of memory in a computer affect: I. The type of program we can run, and type of work to do. II. The speed (to store/write and to retrieve/read information). III. The cost of the computer and the cost of processing data.  24 Memory There are two basic categories of memory: I. Primary/Main memory. II. Secondary/Auxiliary storage. Main Auxiliary Instant storage. Permanent storage. Small amount of information stored Much larger amount of information. Fast and closer to the CPU. Relatively slower & away to the CPU. Used to store 3 types of information: Used to store data, files & applications 1. Data being processed by CPU that are not currently under processing. 2. Instructions for CPU to process data. 3. Operating system instructions to manage processing.  25 Memory Size & Measurements 8-binary bits= 1 Byte 20 𝐵𝑦𝑡𝑒 One character 1 Kilobyte 210 𝐵𝑦𝑡𝑒 One page 1 Megabyte 220 𝐵𝑦𝑡𝑒 3 Novels 1 Gigabyte 230 𝐵𝑦𝑡𝑒 Large personal library 1 Terabyte 240 𝐵𝑦𝑡𝑒 Research library in a university 1 Petabyte 250 𝐵𝑦𝑡𝑒 All printed material in all libraries in North America 1 Exabyte 270 𝐵𝑦𝑡𝑒 All words ever printed in human history. 1 Zettabyte 290𝐵𝑦𝑡𝑒  26 Random Access Memory (RAM) Address Bit MAR: Memory 0 One cell Address Register 1 MDR: Memory Total m emor y 2 Data Register MAR Remark: MAR & … … MDR used to implement Fetch MDR & Store W or multiple W bits operations. 2𝑛−1 Memory width (W)  27 N=4 Fetch & Store MAR d d d d (d = 0 or 1) Fetch (address) Memory Address (4 input lines) (24 = 16 𝑜𝑢𝑡𝑝𝑢𝑡 𝑙𝑖𝑛𝑒𝑠) ▪ Load the address into MAR. ▪ Decode the address into MAR. 0000 0000 (0) ▪ Copy the contents of that memory location into MDR. 0001 0001 (1) Store (address, value) ▪ Load the address into MAR. 0010 0010 (2) ▪ Load the value into MDR. 4-to-16 ▪ Decode the address in MAR. Decoder Circuit … ▪ Store the contents of MDR into that Memory location. 1110 … … ❖ Decode: Means that the memory unit must translate the n-bit address stored in MAR into the set of 1111 signals needed to access that one specific memory cell. 1110 (14) 1111 (15)  28 Four Types of Primary-Memory: I. Registers ▪ Part of the CPU. ▪ Extremely limited capacity. ▪ Store data & instruction during processing only. II. Cache Memory ▪ Closer to CPU & faster than RAM. ▪ Used to store information (blocks of info) that used most often in the running application. ▪ Those used less often remain in RAM until they are transferred to cache, those used infrequently stay stored in secondary storage.  29 Four Types of Primary-Memory: III. Random Access Memory (RAM) ▪ Farther away from the CPU, when you start a program its loaded into the RAM, as you use the program small parts of instructions and data are sent into the registers and then processed by the CPU. IV. Read only Memory (ROM) Unlike all above, it is nonvolatile Used to store critical instructions, e.g. those needed to “boot” the computer. (safe-guarded info.) ROM: computer only Read from them & user can’t change them. ❖ But, there are other types of ROM: a) PROM: Programmable ROM, user can program it on. b) EPROM: Erasable PROM, can reprogrammed, can be Reprogramed, (erased first) using special tools. c) Flash Memory (Rewritable from of ROM) can be built-in into a system mother-board or installed on a card (Flash-Card).  30 Hierarchy of Memory/Storage Levels in Computers CPU Register S p e ed & C o st Cache S i ze Main Auxiliary External  31 Auxiliary, Secondary, External or Mass-storage A computer RAM is never large enough to store all applications, documents and other system generated files that you work on. ▪ Two-Operations: 1. Writing: copies data from RAM to Hard Drive. 2. Reading: copies data from Hard Drive to RAM. Read/Write Heads used to store and extract data. Three Types of Secondary Storage: 1. Magnetic (Floppy Disk, Hard Disk and Tapes). 2. Optical (CDs and DVDs). 3. Solid State (Flash and Solid-State Memory).  32 Magnetic Storage 1. Magnetic: N S N S Polarity: ❖ Its known that: ▪ Opposite polarities attract each other. N S S N ▪ Identical polarity repel each other. ❖These two magnetic states are used to record data on a disk: While the disk spins, electrical signals on the R/W head change the polarity of tiny magnetic Writing particles on the surface of the surface of the disk to record 0s & 1s. When you open a file, the process is reversed. The polarities of the medium immediately under Reading the R/W head induce an electrical current in the R/W head that is transmitted back to the computer in the form of 0s & 1s.  33 Optical Storage 2. Optical: ▪ Optical storage devices use a laser to burn small, dark pits, into the surface of a disk.  Pits Dark  Lands Shiny & Smooth ▪ “While the disc spins in the drive, a narrow laser-beam is focused on the disk’s surface. The amount of light that is reflected back is determined by whether the beam is focused on a Pit or a Land. Pits reflect less light. ▪ A device called photo-detector measures the light and a circuit converts its reading into a 0 or 1”.  34 Compact Disk ❖CD-ROM, may store up to 660 MB of data ▪ They are rated by their access-time & transfer-rate (performance). ▪ The faster they spin the better their performance. ▪ Spin-Rate 2x, 4x, 6x, 16x etc. [16x times faster than the original CD-Drive] Read only. It is an advantage for documents/software copy rights. ❖CD-R (Recordable) Writ-Once-Read-Many ▪ CD-R disc, can be written on, once only. ▪ Have thin layer of gold with another of green dye. ▪ To Record data the laser forms bumps in the dye-larger. [1: represented by a bump 0: represented by absence.]  35 Compact Disk ❖CD-RW (Rewriteable) ▪ Can be recorded, erased and reused just like disks. ▪ They record data by changing a material from a well-structured crystalline state to less-ordered amorphous state. ❖DVD Discs Digital Video Disk Well-Structured Less-Ordered ▪ Latest generation of optical discs. ▪ This Technology is about to replace: Music-CDs, Videotapes and CD-ROMs Its physical size same as CD-ROM. ▪ DVD-Discs may store up to 4.7 GB on a single-sided, single-layer disc. ▪ Double-sided may stores 9.4 GB. Double-sided & double-layer may stores 17 GB (that is 30 times the capacity of today’s CD-ROM discs).  36 Magneto-Optical storage (MO) Offer longevity, removability, high storage capacity and random access. To record data, the laser heats the optical surface then the particles can be changed to indicate 0s & 1s thru. R/W heads, when the surface cools down the data then hard to erase → More secure than others. Available in two format: ▪ Rewritable. ▪ Write-Once and Read-Many (WORM).  37 Solid State Storage Known as Flash Memory, one of the latest memory technology. Uses solid-state chips, nonvolatile. They have no moving parts → much faster than mechanically operated disks and tapes. One form is PC-Card, can be plugged into slots in the side of notebook and take the place of a hard disk drive. They use less energy. They are Removable. Pop one out when its full and pop in another. Used with PDAs (Private Digital Assistants), organizers, digital camera, mobiles, and other hand held devices. ❖Characteristics of flash-memory: compact, portable, require little energy.  38 Sector Track Platters Hard Disk Structure Cylinder Motor Platter Read/Write head Actuator Jumper Interface Power Supply  39 Memory Memory helps computers operate faster and more efficiently Random Access Memory (RAM) ▪ Memory chips in a PC ▪ Virtual Memory (volatile) ▪ Cache Memory (on the CPU) Read-Only Memory (ROM) ▪ CD-ROM ▪ DVD-ROM  40 Memory hierarchy Processer Main memory Register ▪ Large, inexpensive, slow memory stores entire program and data Cache Cache ▪ Small, expensive, fast memory stores copy of likely accessed parts of larger memory Main Memory ▪ Can be multiple levels of cache Disk  41 Storage Permanence Range of storage permanence: ▪ High end  essentially never loses bits  e.g., mask-programmed ROM ▪ Middle range  holds bits days, months, or years after memory’s power source turned off  e.g., NVRAM ▪ Lower range  holds bits as long as power supplied to memory  e.g., SRAM ▪ Low end  begins to lose bits almost immediately after written  e.g., DRAM  42 Basic Types of RAM SRAM: Static RAM ▪ Memory cell uses flip-flop to store bit. ▪ Requires 6 transistors (used as memory cache). ▪ Holds data as long as power supplied. ▪ Frequently small amount used in cache memory for high-speed access (more expensive than DRAM). DRAM: Dynamic RAM ▪ Memory cell uses MOS transistor and capacitor to store bit. ▪ More compact than SRAM. ▪ “Refresh” required due to capacitor leak. ▪ word’s cells refreshed when read. ▪ Typical refresh rate 15.625 microsec. ▪ Slower to access than SRAM.  43 ROM: “Read-Only” Memory Non-volatile memory: ▪ Holds bits after power is no longer supplied. ▪ High end and middle range of storage permanence. Can be read from but not written to, by a processor in an embedded system Traditionally written to, “programmed”, before inserting to embedded system Uses: ▪ Store software program for general-purpose processor  program instructions can be one or more ROM words ▪ Store constant data needed by system  44 ROM: “Read-Only” Memory Memory to hold software that is not expected to change over the life of the system Magnetic core memory EEPROM ▪ Electrically Erasable Programmable ROM ▪ Slower and less flexible than Flash ROM ▪ EEPROM write/erase one byte but Flash ROM W/E in blocks Flash ROM ▪ Faster than disks but more expensive ▪ Uses  BIOS: initial boot instructions and diagnostics  Digital cameras  45 Hierarchy of Computer Systems 1. Supercomputers ▪ Most powerful computers available (4-10 times faster than mainframes). ▪ First used in Military, now used in scientific research, technical and business. ▪ Especially valuable for large simulation models of real-world phenomena, where complex mathematical representations & calculations are required. ▪ Cray is the leading supercomputer manufacturer, while Intel also manufactured supercomputers. A recent Intel supercomputer can:  Execute over 1 trillion operations per second.  It has over 7,000 processors, thus supports parallel processing.  Thus, it can calculate in 1 second what it would take the people of the US 125 years to calculate manually. ▪ Used to generate extremely realistic scene in many movie special effects. ▪ Size of RAM, Fixed Drive, Registers Size, Max. Integer and number of operations are also very powerful and higher scale than all other computers.  46 Supercomputer Applications: I. Weather Forecasting: The National Oceanic and Atmospheric Administration (NOAA) in the US use Cray supercomputer to model weather for better prediction of weather. Providing early warnings of hurricanes, floods and storms. II. Automotive Design: Japanese Nissan used Cray supercomputer in 1986 to: a) Improve quality of car models. b) Reducing costs. c) Shortening development time. III. Aircraft Design: The Boeing 777 design was modeled using a supercomputer, for more efficient and less costly production. A typical supercomputer calculation result can be displayed as graphic represents “air flow over an automobile, or aircraft. One color to indicate high pressure build-up, another color to indicate low pressure. IV. Movies: Jurassic Park and Star War movies, their graphics design produced by supercomputers. Supercomputers can make many sequences in motion pictures. Specifications: ▪ 60 billion to 3 trillion MIPs (Machine instructions per second) ▪ 8,000 MB (or more) of RAM. ▪ US$ 2 - 4 million. ▪ A size of a car  47 2. Mainframes Also called servers, and time-sharing systems. Less powerful and less expensive than supercomputers. Used in large corporations to centralize data processing and maintain large/shared databases. Occupy an entire room and must be maintained and operated by highly trained staff or specialists. Provide system administrators with better control, security, management and maintenance on data, information and applications. IBM, HP and Sun are manufacturers of mainframes. Application examples: ▪ Airline Reservation System ▪ Inventory Control System ▪ Payroll System ▪ Students Grade Calculation and Reporting System. Specifications: ▪ 40 - 4,500 MIPs ▪ 256 - 1,024 MB of RAM. ▪ US$ 1/4 - 2 million (or more). ▪ A size of refrigerator ▪ High capacity of magnetic/optical storage media [In TB (Tera Byte)]. ▪ Several hundreds/thousands of on-line computers/terminals can be linked with mainframes. ▪ Today’s mainframes can handle up to one-billion transaction per day.  48 3. Minicomputers Also called, Midrange, are similar to mainframes in supporting multi-user and multitasking environment but in a smaller scale. Used in scientific research, and engineering applications. Distributing data processing with minicomputers provides flexibility to large companies, instead of centralized computing in one location. Inexpensive compared to mainframes. IBM is the market leader of minicomputers with its AS/400 series. Specifications: ▪ 25 - 100 MIPs ▪ 32 - 512MB of RAM. ▪ US$ 20,000 – 100,000 (or more). ▪ A size of file cabinet.  49 4. Workstations Desktop engineering workstation (workstation for short). Provide very high-speed calculations and high-resolution graphics. Also support multitasking capabilities. Usually come with large displays. Widespread acceptance in scientific community and , more recently, within the business community. Originally more powerful than PCs, but now one of the latest PC may have computing power similar or more than a recent workstation. Examples: IBM’s RISC Systems/6000 and Sun Workstations. Specifications: ▪ 50 - 100 MIPs ▪ 32 - 256 MB of RAM. ▪ US$ 4,000 – 20,000 (or more). ▪ Fits on desktop.  50 5. Microcomputers Also called Personal Computers (PCs) are the smallest and least expensive category of general-purpose computers. First introduced by Apple, then other vendors like IBM followed. A group of PCs usually hooked together to form a network (e.g. LAN) and act as a sort of mainframe like system. They can be classified into three types, based on their sizes: ▪ Desktops (most common ones everyone use them) ▪ Laptops and Notebooks (small, portable and easy transportable) ▪ Palmtops (hand held, but limited in no. of ways for I/O. For example, a Personal Digital Assistant (PDA) is a hand held, palmtop computer uses a pen rather keyboard for inputs. PDAs support hand-writing, and voice-recognition). Specifications: ▪ 5 - 20 MIPs ▪ 16 - 128 MB of RAM (or more). ▪ US$ 1,000 – 2,500 ▪ Fits on desktop  51 6. Network Computer Also known as “thin clients” because they store little data and few applications and do not have full functionality like desktops. Less expensive than standard PCs, and need less maintenance. Used to access networks, they act more like terminals, temporarily, receiving/using data and applications stored some where else. They work best in the following situations: ▪ Users who work with a limited set of programs (secretaries and top-level executives –For email, word- processing etc.). ▪ Shared Desktops (contractors, consultants, part-time employees etc.) ▪ Remote users who are difficult to support (less to go wrong and less to fix in such computers). ▪ Whenever security is critical. Specifications: ▪ 1 - 5 MIPs ▪ 4 - 16 MB of RAM. ▪ US$ 500 – 1,500 ▪ Fits on desktop.  52 Hierarchy of Computer Systems Supercomputer Mainframe Minicomputer Workstation  53 The Central Processing Unit (CPU) The “brains” of the computer. Performs calculations and completes instructions. Performance based on clock speed: how many instructions can it accomplish in a cycle. Pentium 4: 2.0 GHz chip operates at 2 billion cycles per second…can do one instruction per cycle per pipeline (“20 stage depth pipeline” says the information Intel provides on their website: www.intel.com).  54 CPU It performs the computations or “number crunching” inside any computer. The CPU is made up of millions of microscopic transistors embedded in a circuit on a silicon chip, that’s why it is called a chip. The CPU has different portions: ▪ Control-Unit (CU), controls the flow of information between the computer system components. ▪ Arithmetic-Logic-Unit (ALU), performs the arithmetic and logic operations ▪ Registers, store very small amount of information (data & instructions) for short period of time.  55 The Central Processing Unit (CPU) Storage Memory Control Arithmetic Unit Logic Unit (ALU) Registers Cache Input/Output Flags Memory  56 How Does the CPU work? Inputs (data & The ALU receives The transformed instructions) come Inputs are stored in the data and data stored from software registers until they instructions from temporarily into programs. Data may are sent to the next the registers and another register and be entered from the step. makes the desired then out of the CPU keyboards, or read computation. (monitor, or file). from a data file. ❖ Notes: ▪ CPU can only process binary data, so data & instructions are translated into binary form. ▪ CU directs the flow of data and instructions within the chip. ▪ Data and instructions travel within electrical pathways called buses.  57 Machine Instruction Cycle Diagram CU Register ALU RAM  58 Machine Instruction Cycle This cycle of processing known as “machine instruction cycle” occurs millions of times per seconds. The speed is commonly measured by the number of instructions the chip processes per second - machine instruction cycles per second (MIPS). The speed depends on the following factors: ▪ The preset speed of the clock that times all chip activities, measured in megahertz (MHz) The faster the clock speed, the faster the chip. ▪ Word-length, the no. of bits that can be processed at one time (8, 16 or 32-bit). ▪ Bus-Width, the physical avenues down which the data travel as electrical impulses. The wider the bus the faster data can be moved. Buses measured in microns (1,000,000,000 microns = 1 meter). ▪ The physical design of the chip, the more compact and efficiently laid out, the faster the processing. The more transistors the faster the chip. [factory & material vs. chip & data/instructions].  59 Advancing the chip design: Increase miniaturization of transistors. Decreasing line-width (distance between transistors). Components layout design Vs efficiency. Using better conductive materials (for better flow of electricity) ▪ Silicon ▪ Gallium Arsenide ▪ Silicon Germanium Amount of basic instructions programmed into the chip: ▪ Complex Instruction Set Computing (CISC), very comprehensive. ▪ Reduced Instruction Set Computing (RISC), rely on software to provide special instructions.  60 CPU’s Manufactures 1. Intel (www.intel.com) 2. AMD (www.amd.com) 3. Motorola (www.motorola.com) 4. Cyrix (beg. in 1988, and in Nov. 1997 merged with National Semiconductor) 5. VIA Technologies ( www.viatechnology.com) 6. Transmeta Corporation (www.transmeta.com, Founded in 1995)  61 COPROCESSORS Additional chips which could be purchased with 386 and older chips. An option to help reduce the cost of computers. Coprocessors allow the hardware for floating-point math. Math coprocessors will speed your computer's operation. Computers now no longer require the extra purchase of the math compressor.  62 COMPATIBLE INTEL PROCESSORS Several companies such as AMD and Cyrix are also developing processors such which are completely compatible with Intel processors. This means that they are capable of emulating every processor instruction in the Intel chips. Parallel Processing - Method of evenly distributing computer processes between two or more computer processors. This requires a computer with two or more processors installed and enabled, an Operating System capable of supporting two or more processors, and software programs capable of evenly distributing processes between the computer processors.  63 Clock Speed Also could be called Clock Rate, clock speed is the speed at which the microprocessor executes each instruction. The CPU requires a fixed number of clock ticks, or cycles, to execute each instruction. The faster the clocks rate, the faster the CPU, or the faster it can execute instructions. Clock Speeds are usually determined in MHz, 1 MHz representing 1 million cycles per second, or in GHz, 1 GHz representing 1 thousand million cycles per second.  64 Dual Processors Dual Processors: Computer that has two separate processors that work together. Dual processors are commonly used for intensive processing demands and improves the computer's overall processing efficiency. It is important to note that not all operating systems and software programs support dual processors. Often this is true with older operating systems such as Microsoft Windows 98; however, newer operating systems such as Microsoft Windows XP do support dual processors. MIPS - Short for Machine Instructions Per Second, MIPS is the approximate number of commands carried out in one second. MIPS is a measurement of speed for a processor or program.  65 Overclocking The idea is simple enough; make the computer's processor run faster than its cloock speed to gain more performance without paying for it. Overclocking a computer's processor or memory causes it to go faster than its factory rated speed. Overclocking a computer's processor or memory causes it to go faster than its factory rated speed. A processor rated at 2.4GHz might be overclocked to 2.5GHz or 2.6GHz, while memory rated at 200MHz might be pushed to 220MHz or higher. The extra speed results in more work being done by the processor and/or memory in a given time period, increasing the overall computing performance of the PC.  66 Bus System The physical connection that makes it possible to transfer data from one location in the computer system to another. Group of electrical conductors for carrying signals from one location to another. Line: each conductor in the bus. 4 kinds of signals: I. Data (alphanumeric, numerical, instructions). II. Addresses. III. Control signals. IV. Power (sometimes).  67 Bus System Connect CPU and Memory. I/O peripherals: on same bus as CPU/memory or separate bus. Physical packaging commonly called backplane. ▪ Also called system bus or external bus. ▪ Example of broadcast bus: Part of printed circuit board called motherboard that holds CPU and related components. Protocol: Documented agreement for communication specification that spells out the meaning of each line and each signal on each line. Throughput, i.e., data transfer rate in bits per second: data width in bits carried simultaneously.  68 Point-to-Point vs. Multipoint Bus Computer Computer Serial Modem port Computer Computer CPU Memory Control ALU Unit Disk controller Video controller Examples of point-to-point buses Examples of multipoint buses  69 Bus Interface Bridge  70 PCI Bus Short for Peripheral Component Interconnect, a local bus standard. Developed by Intel Corporation. PCI is also used on newer versions of the Macintosh computer. PCI is a 64-bit bus, though it is usually implemented as a 32-bit bus. It can run at clock speeds of 33 or 66 MHz. At 32 bits and 33 MHz, it yields a throughput rate of 133 MBps. Although it was developed by Intel, PCI is not tied to any particular family of microprocessors. Using PCI, a computer can support both new PCI cards while continuing to support Industry Standard Architecture (ISA) expansion cards, an older standard. PCI is now installed on most new desktop computers, not only those based on Intel's Pentium processor but also those based on the PowerPC.  71 Industry Standard Architecture Industry Standard Architecture (in practice almost always shortened to ISA) was a computer bus standard for IBM compatible computers. ISA originated as an 8-bit system in the IBM PC in 1981, and was extended in 1983 as the XT bus architecture. The newer 16-bit standard was introduced in 1984. Designed to connect peripheral cards to the motherboard. The 8-bit bus ran at 4.77 MHz, while the 16-bit bus operated at 6 or 8 MHz. In reference to the XT bus, it is sometimes referred to as the AT bus architecture.  72 Accelerated Graphics Port AGP Bus is short for Accelerated Graphics Port, an interface specification developed by Intel Corporation. AGP is based on PCI, but is designed especially for the throughput demands of 3-D graphics. Rather than using the PCI bus for graphics data, AGP introduces a dedicated point-to-point channel so that the graphics controller can directly access main memory. The AGP channel is 32 bits wide and runs at 66 MHz. This translates into a total bandwidth of 266 MBps, as opposed to the PCI bandwidth of 133 MBps. AGP also supports two optional faster modes, with throughputs of 533 MBps and 1.07 GBps.  73 Instruction Direction given to a computer. Causes electrical signals to be sent through specific circuits for processing. Instruction set: ▪ Design defines functions performed by the processor. ▪ Differentiates computer architecture by the:  Number of instructions.  Complexity of operations performed by individual instructions.  Data types supported.  Format (layout, fixed vs. variable length).  Use of registers.  Addressing (size, modes).  74 Instructional Elements OPCODE: task (represented by binary) Source OPERAND(s) Addresses Result OPERAND ▪ Location of data (register, memory)  Explicit: included in instruction  Implicit: default assumed Source Result OPCODE OPERAND OPERAND  75 CISC vs. RISC Complex Instruction Set Computer Reduced Instruction Set Computer (CISC) (RISC) ▪ Many forms of instructions (some special ▪ Specific list of supported instructions (Want purpose, but chip must support them all). to do something else? Find a combination ▪ x86, Pentium of instructions to accomplish the task) ▪ Power PC (Motorola), Alpha, IBM RISC System/6000, Sun SPARC, MIPS Difference is speed of execution: RISC is faster, but may require longer instruction combinations to accomplish the same task as a CISC  76 CISC Architecture Characteristics: ▪ Few general purpose registers ▪ Many addressing modes ▪ Large number of specialized, complex instructions ▪ Instructions are of varying sizes  77 RISC Features Limited and simple instruction set Fixed length, fixed format instruction words ▪ Enable pipelining, parallel fetches and executions Limited addressing modes ▪ Reduce complicated hardware Register-oriented instruction set ▪ Reduce memory accesses Large bank of registers ▪ Reduce memory accesses ▪ Efficient procedure calls  78 CISC vs. RISC Processing