Computer Hardware
This lesson covers:
– Personal Computers and their Systems
– Mobile computers
• Laptops, tablets, smartphone
– Hardware and software components
– Information about buying computers and
system components
– Information about troubleshooting a system
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Components of a personal
computer
– Motherboard (system board)
• Slot for processor
• Fan and connector to processor
• Slots for main memory (DRAM)
– Volatile (data is lost if power is off)
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BIOS typically in (flash) ROM memory
Clock generator
Power connectors
Interface to buses for i/o devices
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System unit
• System unit houses
– main circuit board
– other storage devices (hard disk, optical disk
drives, etc.)
– typically contains modem, graphics card,
sound card, and network interface card (NIC)
• Probably wired and wireless NICs (adaptors)
– may also contain antenna and speakers
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Sound system
• Output device for digitally represented
sound (music, speech, sound effects for
system purposes, such as starting up, mail
messages, errors)
• Sound card sends signals to speakers that
may be external or built into the system unit
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Display system
• Visual output
• Graphics card converts digital data (such as
documents, photos, and videos) to images
for display devices (such as monitors,
screens)
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Network and Internet Access
• Adaptor is typically inside the System Unitconnects with a cable to a modem and then
is then connected to a Router for connection
to a LAN and/or the Internet
– In most wireless networks, modems connect to
an Access Point that then connects to other cells
or to a Router
– Peer-to-peer wireless networks connect to each
other
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Buying a desktop computer
• Desktop computers do not run on batteries
– Must be plugged into an electrical output
• Price ranges from about $300- $1000
• Apple computers are closer to $1300-2000
• Components stored in towers- vertical
system units for ease of modification or in
screen case
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Desktop and Portable Computers
• The term form factor refers to the size and dimensions of a
component, such as a system board or system unit
• A desktop computer fits on a desk and runs on power from
an electrical wall outlet
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Portable & mobile computers
• Run on electrical power or batteries (as long
as battery is sufficiently charged)
• Mobility is a great advantage!!!
• Smaller, lighter than desk tops
– Classified as
• Laptops (notebooks)
• Netbooks
• Tablet PCs
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Laptops (notebooks)
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Lightweight, portable personal computer
Prices range from $400 to $4000 and more
Weigh about 5 or 6 pounds
Mobility
Require assignment of frequency bands (typically
by base station)
• Most include Bluetooth and/or 802.11 (also called
WiFi), and cameras and speakers
• Display is not as good as desktops but uses less
power
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Netbook
• (mini laptops)
– About 2 pounds and perhaps 7” - 8” wide
– CD or DVD drive is connected externally
through a serial port
– Cost may be less than $300
– Bluetooth is typically provided at an extra cost
– 802.11 is included
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Tablet Computers
• Excellent portability
– More desirable input capabilities
• Touch-sensitive screen
• Writing or drawing pad
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Keyboard must be attached externally
Some accept voice input
iPad costs about $300 to $1000
Designed for music, video, camera, apps
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SmartPhones
• Convergence of technologies
• Mobility, light to carry, power saving
capabilities
• Camera, video, mail, connection to Internet
• Apps
• Telephony
• Extensive computing, storage via the cloud
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Software & Hardware
Components
• Operating Systems
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Control hardware devices
Provide user with friendly interface
Manage application programs
Provide protection and security services
• Applications Programs
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Operating systems
• As the size of memory in portable
computers has increased, the same
operating systems as desk tops are being
used: typically Windows, Mac, Linux
• Android is built on top of a Linux kernel
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Home Computer Systems
• Netbooks, desktops, etc. may be networked
together
• Used for personal finances (e.g., taxes) and
entertainment, photoshop, word processing,
digital cameras, downloading music, games,
movies)
• Internet applications (e-mail, facebook, ecommerce, etc.)
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Gaming PCs
• High end desk top computers
– More memory
– Better sound
• Digitizing analog sound uses more samples
– Better video
• Digitizing analog pictures takes more samples
• Higher resolution
– More processing units
• Multiple cores
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Gamer Paladin E810
http://www.ibuypower.com/Info/chimera4se.aspx
• Chimera 4 E-1 $979 and up (not top of the line)
• Intel® Core i5-4670k Processor(quad core)
8GB or 32GB of memory
120 mm Liquid CPU Cooling
• 8GB DDR3 1600 Memory ( DRAM)
• 1TB SATA-III Hard Drive
• Gigabyte GA-X87 HD3 Motherboard
Windows 8
Tower
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Small business systems
• Desk tops typically considered more reliable, less
likely to be stolen (or lost), easier to repair
• Typically do not have expensive graphics cards,
audio systems, perhaps not even speakers
• Do have business software
– Database, spreadsheets, accounting, etc.
• Connection to Internet may be filtered
• Employee smartphones may be connected
– Security issues
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What should you buy?
• Research the topic! Set a budget!
– My opinion is that even the cheapest computers
today have more than adequate speed, main
memory and hard disk storage for most usage
– Check Consumers Report or the Internet for
reliability
– If you want specific peripherals or software,
make sure the computer you buy is compatible
– Apple has great graphics for video editing, etc.
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Compatibility
• You want your programs from school or
work to be compatible with your home
computers
– Windows OS today typically runs on Apple
computers. Linux OS typically can be installed
on Windows and Apple platforms
– Check on this before you buy your computer
• You want to be able to run Windows
applications, particularly your old programs
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Purchasing software
• Most PCs have an operating system and a
browser installed
• Other software (for example, virus
scanning) may be free for limited period
• Typically you will have to install software
for word processing, spreadsheet, Internet
security (although Windows and Apple
have their own security programs installed)
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Upgrading your system
• Easy to add external components– Perhaps plug into the serial (USB) port –
• You’ll need a cable (like a printer cable)
– External hard drive ($100), mouse ($15 - $50
for wireless), keyboard, add second display
screen ($100 or more), new speakers ($100 or
more)
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Upgrading your system
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Internal – more difficult; takes longer
Replace mother board (may not pay)
Replace processor (may not pay)
Add memory
Replace graphics card
Replace CD or DVD drive
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“Modders” custom alter their
computers
• Add lights, see through cases, paint
machines, add components as any hobbyist
might
• Parts available at Radio Shack and on line
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Other issues
• Warrantee
– How long; how much does it cost?
• Technical Support
– Free? how long does it last? Is the staff any
good (go to the Internet for this)
• Repairs
– Where are the repairs made- are shipping costs
covered? What is the turnaround time?
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Computer Performance
• (micro) processor specifications
– 3.33 GHz indicates speed of processor clock
• Clock sets pace for instruction execution
• Megahertz (MHz) or Gigahertz (GHz) specifies the
number of cycles per second, which affect the
number of instructions that can be executed
– some instructions need multiple cycles
– Pipelined architecture may enable multiple instructions to
be executed in a smaller number of cycles
• Generally more cycles means more instructions/sec
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FSB
• FSB or front side bus
– A bus is a set of wires and circuitry that carry
data, addresses, and control information
between processor & memory and devices
– 1333 MHz FSB is a pretty fast bus by today’s
standard
• Processor and memory continually pass data
between each other – bus speed is crucial
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Words
• Word size is the number of bits that the
processor works on at a time (size of
internal registers), possibly also the number
of bits transferred to or from memory at a
time
• Typically 32-bit or 64-bit architectures are
used today
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Cache
• Cache is a high-speed memory
– RAM cache, cache memory, CPU cache or
internal cache are all terms for the cache that is
between the processor and main memory
• More expensive, faster, but smaller than main
memory
• Typically in the Mbytes today
– L1 cache is inside the processor; L2 cache is
external - between processor and memory
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RISC and CISC instruction sets
• CISC architecture uses many, variable size,
powerful instructions
• RISC architecture uses a small set of fixed
size, comparatively simple instructions
• Intel and AMD use CISC architecture
• Important issue to consider when told an
execution rate of instructions/second
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Specialized graphics instructions
• MMX, AVX, SSE5 are enhanced
instruction sets (only for CISC architecture)
• Easier for graphics programmer
• Typically speeds up graphics and video
applications, but only for software that is
designed to use these instructions
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Serial, parallel and pipelined
processing
• You bake a pizza pie in your oven. After it
is finished, you decide to bake another. The
pies are baked serially.
• Your two friends bake pies in their own
ovens. You three are working in parallel.
• You make the dough while one friend
shapes and the other bakes the pies in the
oven(s). You are pipelining your work.
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Multi-core processor
• Processor contains circuitry for multiple
processing units.
– OS and software must utilize the multiple cores
– With current technology, clock speeds have
reached close to their limit
– Good for games
• 1 core can handle sound, another core can do
rendering, perhaps a third handles display
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Evaluating performance
• Laboratories run tests (benchmarks) to
estimate the speed of a microprocessor
• AMD (Athlon X2) and Intel (Core 2 quad)
have most of the microprocessor market
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•
Intel® Core™2 Quad Processor Q8200 (4M Cache, 2.33 GHz, 1333 MHz)
Advanced Micro Devices
• Apple switched from Motorola (RISC) to
Intel in 2005
• IBM makes RISC processors for servers
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Random Access Memory
• RAM means that it takes the same amount
of time to get to any addressable unit
• The cache in the system unit is also RAM
– Cache is usually denoted as SRAM
• Main memory is frequently denoted as
SDRAM (Synchronous dynamic RAM)
– SDRAM and SRAM are volatile (lose contents
if power is turned off)
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Random Access Memory
• Microscopic capacitors hold the bits that represent data
• Most RAM is volatile
– Requires electrical power to hold data
CLICK TO START
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Compare RAM to hard disk
• RAM is smaller and more expensive
• RAM is much faster and more reliable
– RAM has only electronic units while disks have
mechanical parts
• CPU works directly with program and data
that are stored in main memory
• However, because RAM is volatile,
anything stored there is lost if power is lost
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How much RAM do you need?
• Check any application before you install it.
• Check task manager/performance for
amount of free RAM (physical memory)
• Most systems running Windows 7 need at
least 1 GB of RAM.
– Games, video need more memory
• Personal computers may have 8GB of RAM
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Can you run out of memory?
• Windows 7, Apple, etc. use part of the hard
disk to hold parts of program (divided into
pages) that are not currently in use
– Called swap area
– This “virtual memory” is used by systems to
swap different pages between RAM and disk
– Large performance degradation occurs when
too much page swapping occurs
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RAM specifications
• Today, most RAM stores data in capacitors
• SDRAM at 1066MHz is faster than 10 MHz
• Measures # of cycles per second
– But 10ns RAM is faster than 12ns (12*10-9 sec)
• This measures how long one cycle takes
– DDR (DDR2, DDR3) means dual-channels
• Two channels on the bus to transfer data between
processor and memory
– Typically installed in a DIMM
• (dual inline memory module)
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question
• What does 2GB Dual Channel DDR2
SDRAM at 800 MHz (max 4 GB) mean?
– 2GB is the amount of bytes in main memory
– Dual channel DDR2 specifies two paths to the
CPU (faster than 1 channel)
– SDRAM is volatile main memory (common)
– 800 MHz measures RAM speed
– You can install up to 4GB more – at most
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Read-only memory (ROM)
• ROM is non-volatile, not changeable
– Cannot be written to – more secure
– Typically a startup ROM (or variations of
ROM) routine is stored in a single integrated
circuit plugged into the board to boot system
• ROM BIOS (basic input/output system) checks the
CD/DVD drive first (at fixed address) to see if it
holds a system disk, otherwise goes to hard disk (at
known address) to load the Operating System
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EEPROM
• Electrically Erasable Programmable ROM
– Configuration information is stored semipermanently
– Not volatile, but must be able to be changed
when you add more memory, etc.
– You can make changes during setup, if you
know what you are doing (F1 while computer is
booting)- language, time, date, memory
– Get out of Setup with ESC (exit)
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Storage devices
• Data Storage System consists of
– Storage device – term used for mechanical unit
• Retrieves and writes to the storage medium
• Hard disk drives, tape drives, CD and DVD drives,
flash drives, external disk drives, SANs
– Storage medium – unit that contains data
• Disk, tape, CD, DVD, flash memory
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SSD and HDD
• Sold State Drive/ Hard Disk Drive
• Secondary storage; Both non-volatile
• HDD- Mechanical arm with read/write head
– Potential for disk crash
– $50 for around 500 GB
• SSD all electronic parts
– $410 for about 480GB
– Possibly less reliable for numerous writes
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Data representation in storage
• Conceptually, two charges stored in
capacitors in memory are transmitted as
perhaps 2 voltage levels on a bus to a
device, where it is stored as perhaps two
magnetic or optical states
• This is a simplification
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Factors to consider in choosing
storage technology
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Cost
Size
Speed
Versatility and portability
Durable (robust)
Direct or sequential access
Data transfer rate
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Hard disks
• Magnetic (bit determined by magnetic
orientation of a particle)
– Strong magnet can wipe out data
– Loses magnetic orientation over time
• Mechanical components to read/write data
to disk (can have a head crash)
• Holds a lot of data in small size unit; fast
access; comparatively cheap
• Nonvolatile
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Hard Disk Technology
• Hard disk technology is the preferred type of main storage
for most personal computers
• Not as durable as many other storage technologies
– Head crash
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Hard disk metrics
• Assume 160 GB 8 ms 7200 RPM HD costs $160
– Cost is $1 per gigabyte or 10MB per penny
– 8 ms refers to access time
• the smaller the better
– 7200 revolutions per minute (RPM)
• The faster the better
– Specifications may include transfer rate (of
perhaps 50MB/s ) dependent on controller
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Hard disk controller
• Technologies for controllers include SATA
(Serial Advanced Technology Attachment),
Ultra ATA, EIDE, and SCSI
• Hard drive manufacturers mount controller
circuit on the disk (you don’t have a choice)
– Controller communicates with device driver in
processor to transfer data, commands, addresses
– DMA (UDMA) transfer data directly to
memory
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CD, DVD, and Blu-ray technology
• Optical storage
– Bits stored as microscopic light (lands) and
dark (pits) spots
– Light is reflected differently from light or dark
colors – interpreted as 0s and 1s
• CD – perhaps 700 MB of data; 80 minutes
of music
• DVD – 4.7 GB (double layer stores 8.5GB)
• Blu-ray 25GB per layer
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Comparing CD, DVD, Blu-ray
• Transfer rates of perhaps 64Mbps (CD)
• 297 Mbps (DVD)
• 1 layer Blu-ray (36Mbps)
– Multi-layered up to 432Mbps
• Each uses different data formats for
recording different types of data
– DRIVERS OFTEN ARE NOT COMPATIBLE
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Solid State Storage
• Flash memory is a popular type
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Non-volatile
Electronic (no mechanical parts)
Requires little power
Immune to magnetic interference, temperature
fluctuations
– Capacity less than hard drives
– Tends to “wear out” with use faster than disks do
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USB flash drive
• Solid state; built-in connector to USB port
• portable
– Vulnerable to viruses
• Cheap
• Capacity of perhaps up to 64GB
• Transfer rate of up to perhaps 28MB/second
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Storage Wrap-up
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Software for devices
• Manufacturers provide software called
“device drivers” to communicate with
controllers
– Windows OS recognizes a number of devices
(flash drives, external hard drives) and
configures system automatically – called Plug
and Play
• You may have to load device driver yourself from
supplied disk or from the Internet
– Always “safely remove hardware” [taskbar]
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Hardware Security and
Maintenance
• Do not leave notebook computer unattended
• If you leave it in the car, lock it up.
• Record tracking information of notebook
and store it separately
• Use an anti-theft device
– STOP plates contain tracking mechanisms
– Cables, motion sensor alarms
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Surge Protection
• Always use a surge strip (suppressor)
– You frequently have small surges of power in
your home – perhaps when the air conditioner
goes on
– Even small surges can cause gradual damage to
computer equipment
– Large surges will destroy computers
– Unplug surge strip during lighting storm
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UPS
• Provides battery backup in case of power
failure
– Check on the amount of time (limited)
• UPS unit may also include surge protection
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Basic Maintenance
• Clean keyboard (unplug first)
– Do not eat or drink while typing
• Screen
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Clean regularly
Turn it off to see smudges better
Do not scrub
Do not spray cleaning liquid directly on screen
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Temperature
• Keep computer in cool place
• Keep area free around computer
– Internal fans cool equipment
– (graphics equipment particularly sensitive)
• You can try to blow air through the
equipment, but turn it off first.
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Software maintenance
• Back up files regularly
• Run disk cleanup and disk defragmenter
– If system does not do so automatically
• Delete your browser’s history and cache
files
• Automatically update OS (patches) and
virus protection
• Scan your computer for viruses
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Troubleshooting
• First, check all cables
• If system hangs, shut if off, count to 20,
turn it on again.
– Sometimes that works if problems are transient
• Run your virus protection
• Check the Internet for a similar problem
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Disposal of computer
components
• Be sure that all sensitive data is erased.
– Write over multiple times
– There are programs for this.
• Or remove your hard disk before disposing
of your computer.
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Where does e-garbage go?
• Discarded computer components generate
tons of toxic waste
– Cathode-ray tube monitor can contain 8 pounds
of lead
• Should disposal be taxed?
– Might make environmentally friendly
components more competitive
• Users and manufacturers must cooperate
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