Computer Hardware Evaluating your system components. © 2006 Prentice-Hall, Inc. 1 System Topics • To buy or upgrade? • Evaluating your system: – – – – – – CPU RAM Storage devices Video output Sound systems Computer ports • System reliability © 2006 Prentice-Hall, Inc. 2 To Buy or To Upgrade? • Things to consider: – – – – Moore’s Law – Double every 18 months Cost of upgrading vs. buying Time installing software and files Needs and wants © 2006 Prentice-Hall, Inc. 3 Assessing Your Hardware: Evaluating Your System • Assess the computer’s subsystems • The subsystems include: – – – – – – CPU RAM Storage devices Video Audio Ports © 2006 Prentice-Hall, Inc. 4 Evaluating the CPU • How does the CPU work? – Control unit – Coordinates activity of components – Arithmetic logic unit (ALU) – Performs calculations – Machine cycle: 4 steps Fetch - Gets data from RAM Decode – Information it can read Execute – Executes instruction Store – Stores result to RAM – Speed: Cycles per second Mhz – Megahertz 1 million Ghz – Gigahertz 1 billion © 2006 Prentice-Hall, Inc. 5 Upgrading the CPU • Expensive – Usually the most expensive part • Easy to install • Motherboard compatibility • Heat sink and Fan © 2006 Prentice-Hall, Inc. 6 Evaluating RAM • Random access memory (RAM): – Temporary storage (memory) – Volatile • Memory modules: – SIMM - Single in-line memory module, used in pairs – DIMM – Dual in-line memory module, one at a time – RIMM – Rambus in-line memory module • Types of RAM: – SRAM – Static, refreshment not needed – DRAM – Dynamic, refreshment needed – SDRAM – Synchronous DRAM, synchronizes with CPU © 2006 Prentice-Hall, Inc. 7 Adding RAM • Increase system performance • Things to consider: – Type of RAM module – Amount of RAM: Maximum limit Number of slots Operating system Applications running at the same time © 2006 Prentice-Hall, Inc. 8 Evaluating Storage • Types of storage devices: – – – – – Hard drive Floppy drive Zip disk drive CD/DVD Flash memory © 2006 Prentice-Hall, Inc. 9 Storing Data • Magnetic media: – Metal platters: Track Hard disks – Plastic film: Floppy disks Zip disks • Tracks – Circles • Sectors - Wedges • File Allocation Table – Catalog to keep track of file locations © 2006 Prentice-Hall, Inc. Sector 10 Storing Data • Optical media: – – – – – – CD ROM CD-R CD-RW DVD ROM DVD-R DVD-RW • Laser • Pit – 1 micron diameter = 0 • Land - Raised area = 1 © 2006 Prentice-Hall, Inc. 11 The Hard Disk Drive • Storage capacity up to 500 GB • Access time is measured in milliseconds Platters • Data transfer rate is measured in megabits or megabytes per second • Spindle speed is measured in revolutions per minute (rpm) Read/write head Access arms © 2006 Prentice-Hall, Inc. 12 Portable Storage • Gives us the ability to move data from one computer to another • 4 Types of portable storage devices: – Floppy disk: Capacity 1.44 MB – Zip disk: Capacity 100 MB to 750 MB – CD-R, CD-RW, DVD-R, DVD-RW: Capacity 700 MB to 9.4 GB – Flash drive: Capacity 32 MB to 1 GB © 2006 Prentice-Hall, Inc. 13 Upgrading Storage • Hard drive options: – Replace current drive with a larger capacity drive – Install an additional hard drive • Other options: – Zip drive – Replace CD ROM with CD-R/RW or DVD-R/RW – Flash card reader – Flash memory drive © 2006 Prentice-Hall, Inc. 14 Evaluating Video • Two components: – Video card (adapter) – Monitor © 2006 Prentice-Hall, Inc. 15 Video Cards • Process binary data into images • Contain memory known as video RAM (VRAM) • Control the number of colors a monitor can display (bit depth) – VGA – Video Graphics Array 4 bits 16 colors – True color (SVGA) Super Video Graphics Array 24 bits (32-bit is the same as a 24 bit color with a 8-bit alpha channel). 16 million colors © 2006 Prentice-Hall, Inc. 16 Monitors • Things to consider: – Types: CRT or LCD – – – – Size: 15, 17, 19, or 21 inch Can be widescreen Resolution: Increasing resolution allows more to be displayed – Dot pitch: – .31mm or less – Refresh rate: 75 Hz or higher © 2006 Prentice-Hall, Inc. 17 Evaluating Audio • Speakers: – Amplified – Not amplified – Sub-woofer • Sound card: – Process digital data into sounds – 3D sound cards – Surround sound Dolby Digital 5.1 © 2006 Prentice-Hall, Inc. 18 Evaluating Ports • Ports are used to connect peripheral devices to the computer • Things to consider: – Devices you want to use – Ports needed for the devices © 2006 Prentice-Hall, Inc. 19 Types of Ports • • • • • • • Serial Parallel Universal serial bus FireWire Ethernet IrDA Bluetooth © 2006 Prentice-Hall, Inc. LPT 1 Port PS/2 PS/2 Port Connectors USB Ethernet USB FireWire Ethernet FireWire Connector jack Printer Connector Port Cable Connector Port Port COM 1 Port Serial Connector Transfers eight bits of data Transfer Transfer rate of speed of 100 4 Mbps; Mbps; Mbps; toradio Uses Transfer Transfers rate data 1 one bit at a Transfer rate ofup 400 Mbps; simultaneously; 12Mbps connects infrared 480Mbps; light computers waves Hot swapping to networks waves time; send 56Kbps data over short Digital cameras distances 20 Adding Ports • Expansion cards: – New port standards • Expansion hubs: – Enables several devices to be connected to a port © 2006 Prentice-Hall, Inc. 21 Evaluating System Reliability • Performance: – Slow – Freezes – Crashes • Upkeep and maintenance: – System tools – Control panel – Update software and hardware drivers © 2006 Prentice-Hall, Inc. 22 Upkeep and Maintenance • System tools: – Disk defragmenter – Disk cleanup Unnecessary files • Control panel: – Add/remove programs – Display – System Device manager © 2006 Prentice-Hall, Inc. 23 Update Software and Hardware Drivers • Software: – Automatic updates – Patches • Hardware: – Download updated drivers © 2006 Prentice-Hall, Inc. 24 The Final Decision • How closely does your system come to meeting your needs? • How much would it cost to upgrade your system? • How much would it cost to purchase a new system? © 2006 Prentice-Hall, Inc. 25 CPU Topics • • • • • Computer switches Inside the CPU Cache memory Computer buses Creating faster CPUs © 2006 Prentice-Hall, Inc. 26 Digital Data: Switches and Bits • Electronic switches: – Vacuum tubes – Transistors – Integrated circuits ON • Binary number system: – Representing numbers – Representing letters and symbols OFF ASCII Unicode © 2006 Prentice-Hall, Inc. 27 Electronic Switches • Non-mechanical devices in computers that open and close circuits • Types of electronic switches: – Vacuum tubes – Transistors: Semiconductors – Integrated circuits © 2006 Prentice-Hall, Inc. 28 Switches Representing Data • The on/off state of a switch represents one bit of data • Bit (binary digit): OFF ON – On = 1 – Off = 0 OR 0 © 2006 Prentice-Hall, Inc. = 1 bit 1 29 The CPU: Processing Digital Information • CPU components • Types of CPUs • What the CPU does: – Machine cycle: System clock Cache memory © 2006 Prentice-Hall, Inc. 30 The CPU • Also known as a microprocessor or processor • Executes instructions • Components include: – – – – Control unit Arithmetic logic unit (ALU) Registers – memory storage Cache memory © 2006 Prentice-Hall, Inc. 31 © 2006 Prentice-Hall, Inc. 32 The CPU’s Machine Cycle • Also known as the processing cycle (4 cycles) • Fetch: – The Control Unit searches cache memory and then RAM for program instructions – Instructions are moved to the Control Unit • Decode: – The Control Unit reads and prepares the program instructions – The instructions are sent to the ALU • Execute: – The ALU performs the calculations • Store: – The results are stored in the registers (storage in the CPU) © 2006 Prentice-Hall, Inc. 33 Book Example © 2006 Prentice-Hall, Inc. 34 © 2006 Prentice-Hall, Inc. 35 The System Clock • Located on the motherboard • Controls the CPU’s processing cycles • Clock cycle: – Pulse or tick – Oscillating crystal • Clock speed: – Number of pulses per second – Measured in hertz (Hz) – Useful for measuring CPUs in the same family © 2006 Prentice-Hall, Inc. 36 Cache Memory • Small amount of memory located on the CPU chip or near it: used before RAM – Level 1 is on the CPU and is first – Level 2 is on or near the CPU and is second • Stores recent or frequently used instructions and data • Used for quick access by the CPU © 2006 Prentice-Hall, Inc. 37 © 2006 Prentice-Hall, Inc. 38 © 2006 Prentice-Hall, Inc. 39 Buses: The CPU’s Data Highway • Bus: – Electrical pathway used to move data between components – Local bus: Connects the CPU with the memory – Expansion bus: Connects the CPU with peripheral devices 01100010 01001000 01110011 00100111 © 2006 Prentice-Hall, Inc. 40 © 2006 Prentice-Hall, Inc. 41 Bus Performance • Bus clock speed: – Rate of speed data moves from one location to another – Measured in Mhz (millions of clock cycles per second) • Bus width: – The number of bits of data moved on a bus at any one time – Measured in bits: 16 bits 32 bits 64 bits © 2006 Prentice-Hall, Inc. 42 Types of Expansion Buses • ISA and EISA: – Found on older computers – Connects mouse, modem, and sound card • PCI: – Faster than ISA and EISA – Found on modern computers – Connects network, modem, and sound card • AGP: – Used for three-dimensional graphics – Connects the graphics card and memory • PCI-Express – Based on PCI but gets better clock speeds – Replace PCI and AGP © 2006 Prentice-Hall, Inc. 43 Making Computers Faster • Pipelining: – The CPU processes more than one instruction at a time. P4 = 20 pipelines Non-pipelined CPU Instruction 1 Fetch Decode Execute Store Instruction 2 Fetch Decode Execute Store Pipelined CPU Instruction 1 Fetch Decode Instruction 2 Fetch Decode Store Execute Store Fetch Decode Execute Store Instruction 4 Fetch Decode Execute Instruction 3 © 2006 Prentice-Hall, Inc. Execute Store 44 © 2006 Prentice-Hall, Inc. 45 Making Computers Faster • Dual processing: – Two CPUs on the same system – Each processor shares the workload Dual processors • Parallel processing: – Network of computers – Each computer works on a portion of the problem simultaneously – SETI http://setiathome.ssl.berkeley. edu/ © 2006 Prentice-Hall, Inc. 46 Lab Assignment • Build two PCs from Dell © 2006 Prentice-Hall, Inc. 47