Computer and Peripherals n Computer Hardware uRefer only to the Central processing unit (CPU), the circuitry that processes the data, and the computer’s memory. Part 1: Inside the System Unit n Peripherals uAll additional hardware components grouped around the CPU and memory © Peter Lo 2002 1 © Peter Lo 2002 2 Computer Hardware Overview System Unit nIt is a Box-like case that contains computer’s electronic components nSometimes called the Chassis © Peter Lo 2002 3 © Peter Lo 2002 4 1 Exposed System Unit How do computers represent data? n Most computers are digital n Recognize only two discrete states: on or off on 1 1 1 1 1 off 0 0 0 0 0 © Peter Lo 2002 5 © Peter Lo 2002 6 Binary System What is a byte? n Number system with two unique digits: 0 and 1 n Eight bits grouped together is a byte Binary Electronic Electronic 8-bit byte for the number 3 Digit (bit) Charge State 8-bit byte for the number 5 8-bit byte for the capital letter T © Peter Lo 2002 7 © Peter Lo 2002 8 2 Three Popular Coding Systems to How is a Character Sent from Represent Data Keyboard to Computer? ° ASCII - American Step 1: Press letter T Standard Code for Information Interchange Step 2: Electronic signal for letter T sent to system unit ° EBCDIC - Extended Step 3: Signal changed to its Binary Coded Decimal ASCII code (01010100) and Interchange Code stored in memory ° Unicode - coding scheme capable of Step 4: After processing, binary code for letter T is converted to representing all world’s image on output device languages © Peter Lo 2002 9 © Peter Lo 2002 10 Central Processing Unit (CPU) ? Components of the CPU n Interprets and carries out basic instructions that operate a computer n Also called the Processor CPU Control Arithmetic/ Unit Logic Unit (ALU) © Peter Lo 2002 11 © Peter Lo 2002 12 3 Control Unit Machine Cycle? °Four operations of the CPU comprise a machine cycle ° Directs and coordinates operations in computer °Also called instruction cycle Control unit repeats • Instruction time (i-time) - time taken to fetch and decode four basic operations: • Execution time (e-time) - time taken to execute and store ° Fetch - obtain program Control Unit instruction or data item from e-time i-time memory ° Decode - translate instruction into commands ° Execute - carry out command ° Store - write result to memory © Peter Lo 2002 13 © Peter Lo 2002 14 An example of a machine cycle Available CPU Packages 100 x 52 Student enters math problem (100 x 52) into single edge contact (SEC) cartridge computer’s dual inline package (DIP) memory Result in memory displays on monitor’s screen flip chip-PGA pin grid array (PGA) (FC-PGA) package © Peter Lo 2002 15 © Peter Lo 2002 16 4 CPU’s speed Measuring Two Designs used for the CPU ° According to how many CISC millions of (complex instruction set instructions per computing) RISC (reduced instruction second (MIPS) it ° Supports large number set computing) can process of instructions ° CPU executes complex ° Supports smaller instructions more number of quickly instructions ° CPU executes simple instructions more quickly © Peter Lo 2002 17 © Peter Lo 2002 18 Arithmetic/Logic unit (ALU) Pipelining n CPU begins executing second instruction before n CPU component that performs execution part of completing first instruction. Results in faster processing the machine cycle Comparison Machine Cycle (without pipelining) (greater than, equal to, or less than) .and. Machine Cycle (with pipelining) .or. .not. Instruction 1 Arithmetic Logical Instruction 2 (addition, subtraction, (AND, OR, multiplication, and NOT) Instruction 3 division) © Peter Lo 2002 19 © Peter Lo 2002 Instruction 4 20 5 Register System Clock ° Temporary storage area n Synchronizes all computer operations that holds Stores n Each tick is clock cycle data and Stores results instruction instructions of calculation while it is being decoded Stores location Stores data while from where MHz - one million instruction was ALU processes it ticks of system clock fetched GHz – one billion ticks © Peter Lo 2002 21 © Peter Lo 2002 of system clock 22 How do personal computer Microprocessor processors compare? n Single processor chip found in personal computers © Peter Lo 2002 23 © Peter Lo 2002 24 6 Coprocessor Parallel Processing °Using multiple processors simultaneously to execute program faster Chip that assists processor in performing specific tasks One type is a floating-point coprocessor, also known as a °Requires special software math or numeric to divide problem and bring results together © Peter Lo 2002 coprocessor 25 © Peter Lo 2002 26 Memory: The CPU’s Electronic How is memory measured? Scratchpad n Memory is the temporary storage area for n Memory is measured by number of bytes available operating system, application programs, and data n It consists of one or more chips on motherboard n Each byte stored in unique address © Peter Lo 2002 27 © Peter Lo 2002 28 7 Two types of System Unit Memory Random Access Memory (RAM) n Memory chips that can be read from and written to by processor n Most RAM is volatile n The more RAM a computer has, the faster it volatile memory operates Loses its contents when nonvolatile thecomputer's computer's power power is memory isturned turned off off Does NOT lose its contents when computer’s power is memory module turned off © Peter Lo 2002 29 © Peter Lo 2002 30 Two Basic Types of RAM chips Cache n Dynamic RAM (DRAM) n Helps speed computer processes by storing frequently used instructions uMost common type and data uAlso called main memory n Also called Memory Cache, Cache n Static RAM (SRAM) Store , or RAM Cache u Used for special applications such as cache n L1 cache built in processor n L2 and L3 cache not built in u Faster and more reliable than DRAM chips processor n L2 advanced transfer cache most common © Peter Lo 2002 31 © Peter Lo 2002 32 8 Read-Only Memory (ROM) Types of ROM n Memory chips that contain data, instructions, or information that is recorded permanently n Firmware uROM chips manufactured with permanently written data, instructions, or information BIOS n PROM (Programmable Read-Only Memory) Data can only ROM is (basic input/output system) uBlank ROM on which you can place items permanently be read; nonvolatile — Stored on ROM n EEPROM (Electrically Erasable Programmable Read-Only Memory) cannot be Contents not lost Sequence of instructions modified in when computer is computer follows to load uType of PROM containing microcode programmer can ROM turned off operating system and other erase files when you turn on the computer © Peter Lo 2002 33 © Peter Lo 2002 34 Flash Memory CMOS n Nonvolatile memory that can be erased n CMOS stand for Complementary Metal-Oxide electronically and reprogrammed Semiconductor memory n Used with handheld computers and digital n Stores information about the computer cameras, cellular phones, and automobiles utype of disk drives ukeyboard umonitor ucurrent time and date n Uses battery to retain information when computer is turned off © Peter Lo 2002 35 © Peter Lo 2002 36 9 Memory Access Time BUS processor ° Channel that allows devices inside n Speed at which processor can access data from memory computer to communicate with directly each other n Measured in nanoseconds (ns), which is one billionth of a ° System bus connects processor system second and RAM bus n It takes 1/10 of a second to blink your eye; a computer can ° Bus width determines number perform up to 10 million operations in same amount of of bits transmitted at one time time ° Word size determines number of bits processor can interpret and execute at a given time RAM © Peter Lo 2002 37 © Peter Lo 2002 38 Expansion Bus Expansion Slot n Allows processor to communicate with peripherals °An opening, or socket, where fastest memory next fastest circuit board is next fastest inserted into slowest motherboard processor °Expansion card inserted in expansion slot expansion card PCI© busPeter Lo expansion 2002 slots ISA bus expansion slots 39 © Peter Lo 2002 expansion 40 slot 10 How are expansion cards used? Plug and Play n Computer automatically can configure cards and other devices as you install them © Peter Lo 2002 41 © Peter Lo 2002 42 PCMCIA card Flash Memory Card n Credit card-sized device used to add capabilities to n Adds memory to handheld computers, digital notebook computers music players, cellular telephones, and similar n PCMCIA stand for Personal Computer Memory Card devices International Association n Uses include modem, additional memory, and storage © Peter Lo 2002 43 © Peter Lo 2002 44 11 mouse Port keyboard Different Types of Connectors USB °Connects USB external serial port printer (parallel devices to port) system unit speaker monitor microphone game port network telephone telephone line line out in svideo out FM reception © Peter Lo 2002 45 © Peter Lo 2002 46 cable TV byte serial representation byte representation transmission for number 5 for number 1 Serial Port of data (00110101) Parallel Port byte representation byte for number 3 representation byte representation °Transmits one bit of for number 5 fornumber 5 (00110101) byte °Connects devices data at a time representation that can transfer for number 5 °Used to connect (00110101) more than one bit slow-speed devices, at a time, such as a such as mouse, printer keyboard, modem DB-9 female DB-25 male connector connector DB-9 male DB-25 female © Peter Lo 2002 47 © Peter Lo 2002 48 connector connector 12 DVD-ROM Universal Serial Bus port (USB) Bay drive CD-RW n Connector that supports newer peripherals and plug and n Open area inside drive play Zip drive system