Computer Hardware

1
Computer Hardware

• What is all that stuff inside the machine?

2
Computer Hardware
Chapter 2

• Describe the role of the ALU
• List factors that affect performance
• Explain RAM
• Compare storage technologies
• Describe computers expansion bus
• Explain hardware compatibility considerations
• Compare and contrast technologies for peripherals

3
Inside the Box
Section A
Chapter 2
4
Who Made it?

• Not made by the name on the outside
• CPU in US (Intel, AMD)
• mainboard from Taiwan (Asus, Abit, Shuttle)
• Disks come from Singapore or Indonesia (Seagate,
  Western Digital, IBM, Maxtor).
• Memory often comes from Korea
• power supply from a dozen Chinese companies
• Assemblers make money off bulk prices on parts

5
Standards

• Much is set according to industry standards
• Parts come marked for assembly
• Plugs are universal, though many
• BTX replacing ATX standard (for cooling purposes
  mainly)
• Standards groups
• Makes only the chip High-tech

6
How to evaluate systems

• Power
• Noise
• Size
• Keyboard
• Screen
• Most users cannot distinguish anything more
  detailed than what is above, but salesreps will
  try to sell you on the details and not the
  general characteristics

7
Data Representation and Digital Electronics
Section A
Chapter 2
DIP Dual Inline Package PGA Pin Grid
Array DIMM Dual Inline Memory Module SEC
Single Edge Contact
8
Data Representation and Digital Electronics
Section A
Chapter 2
The motherboard houses all essential chips and
provides connecting circuitry between them
9
Division of Duties
10
Microprocessors and Memory
Section B
Chapter 2
Microprocessor Basics Exactly what is a
microprocessor?

• A microprocessor is an integrated circuit
  designed to process instructions
• CPU on a chip

11
Microprocessors and Memory
Section B
Chapter 2

• The CPU has two parts
• ALU (arithmetic logic unit)
• performs arithmetic operations
• performs logical operations
• uses registers to hold data being processed
• control unit directs and coordinates processing.
• The list of instructions that a microprocessor
  can perform is called its instruction set

12
Microprocessors and Memory
Section B
Chapter 2
Microprocessor Performance Factors What makes
one microprocessor perform better than another?

• CPU speed is influenced by several factors
• clock speed Megahertz, Gigahertz
• word size
• Cache Level 1, Level 2 caches
• instruction set size
• Testing laboratories run a series of tests
  (benchmarks) to gauge the overall speed of a
  microprocessor

13
Speed

• CPU speed is bound by other things as well
• Only video games and graphic editors are CPU
  bounded
• Most need to worry about memory
• Low power vs. high power (heat is the enemy)
• 486 was 4 watts
• Pentium III is 80 watts
• Smaller circuits take less to fill, but leak
  more
• What a clock waits on filling the circuits, so a
  faster clock is not the solution
• Voltage is the pump behind the fill and
  increases the heat
• Serial vs. parallel

14
Microprocessors and Memory
Section B
Chapter 2
Can a microprocessor execute more than one
instruction at a time?

• Computers with a single processor execute
  instructions serially (one at a time)
• Pipelining - technology in which the processor
  can begin executing next the instruction before
  it completes the previous instruction
• A computer with more than one processor can
  execute multiple instructions simultaneously,
  referred to as parallel processing
• Supercomputers

15
Microprocessors and Memory
Section B
Chapter 2
Random Access Memory What is RAM?

• RAM (random access memory) - an area of the
  computer that temporarily holds data before and
  after it is processed
• as you type, characters are held in RAM

• RAM is a reusable computing source
• RAM is volatile requires power to hold data

16
Microprocessors and Memory
Section B
Chapter 2
Why is RAM so important?

• It holds the data and the instructions for
  processing the data
• It even houses OS instructions

17
Microprocessors and Memory
Section B
Chapter 2
How much RAM does my computer need?

• RAM is primary storage (main memory)
• Measured in megabytes (MB)
• Use drives amount of RAM
• A computer can use disk storage to simulate RAM.
  This is called virtual memory
• Speed is measured in nanoseconds. 1 nanosecond is
  1 billionth of a second
• It can also be expressed in MHz (millions of
  cycles per second)

18
RAM speed

• Latency (most delay in this setup)
• Generate address request
• Hold on memory bus
• Memory control converts to physical location
• Throughput (burst) this is in the ads
• SDRAM vs. DRAM (Synchronous Dynamic RAM)
• pitching machine v. live game
• RDRAM stacks requests (very expensive)

19
Microprocessors and Memory
Section B
Chapter 2
Do all computers use the same type of RAM?

• RAM is usually configured as a series of DIPs
  soldered onto a small circuit board called a DIMM
  (dual in-line memory module), RIMM (Rambus
  in-line memory module), or SO-RIMM (small outline
  RIMM)
• DIMMs contain SDRAM, RIMMs and SO-RIMMs contain
  RDRAM

SDRAM chip

20
Microprocessors and Memory
Section B
Chapter 2
Read-Only Memory How is ROM different from RAM?

• ROM (read-only memory) is one or more chips
  containing instructions that help a computer
  prepare to process tasks
• ROM is permanent and non-volatile
• Only way to change the instructions on a ROM chip
  is to replace the chip
• Since RAM is empty when a computer is turned on,
  ROM BIOS is used
• ROM BIOS (basic input/output system) is a set of
  instructions that tells computer how to access
  the disk drives and peripheral devices

21
Microprocessors and Memory
Section B
Chapter 2
Where does a computer store its basic hardware
settings?

22
Storage Devices
Section C
Chapter 2
Storage Basics What are the basic components
of a data storage system?

• A storage device, such as a floppy disk drive, a
  hard drive, zip drive, and a CD-ROM drive, is
  used to store the data
• A storage medium is the disk, tape, CD, DVD,
  paper or other substance that contains data
• Storing - writing data or saving a file
• Retrieving reading, loading or opening

23
Storage Devices
Section C
Chapter 2
Whats the difference between magnetic and
optical storage technologies?

• Magnetic storage - stores data by magnetizing
  microscopic particles on the disk or tape surface
• Read-write head - mechanism in the disk drive
  that reads and writes magnetized particles that
  represent data
• Optical storage stores data as microscopic light
  spots (lands) and dark spots (pits) on the disk
  surface
• Data stored on an optical storage device is less
  susceptible to environmental damage

24
Storage Devices
Section C
Chapter 2
Whats the difference between magnetic and
optical storage technologies?

25
Storage Devices
Section C
Chapter 2
Whats the difference between magnetic and
optical storage technologies?
CD-ROM PITS

26
Storage Devices
Section C
Chapter 2
Which storage technology is best?

• Speed - measured by access time and data transfer
  rate
• Access time - average time it takes a computer to
  locate data and read it
• millisecond one-thousandth of a second
• Random access - ability of a device to jump
  directly to the track or sector holding the data
• floppy disk, hard drive, CD, DVD, zip disks
• Storage capacity - maximum amount of data that
  can be stored on a storage medium

27
Storage Devices
Section C
Chapter 2
Floppy disk Technology Why is it called a
floppy disk?

• A floppy disk is a round piece of flexible mylar
  plastic covered with a thin layer of magnetic
  oxide and sealed inside a protective casing

28
Storage Devices
Section C
Chapter 2
How does a hard disk work?
Click to start

29
Storage Devices
Section C
Chapter 2
Whats all this business about Ultra ATA, EIDE,
SCSI, and DMA?

• A hard drive mechanism includes a circuit board
  called a controller that positions the disk and
  read-write heads to locate data
• Popular drives
• Ultra ATA (AT attachment)
• EIDE (enhanced integrated drive electronics)
• SCSI (small computer system interface)
• Head crash - when a read-write head runs into a
  dust particle or other contaminant on the disk
• head crash damages some data on disk
• triggered by jarring the hard disk while in use

30
Storage Devices
Section C
Chapter 2
Tape Storage Whats the purpose of a tape
drive?

• Tape
• most popular form of storage in 1960s
• Requires sequential access
• Inconvenient and slow
• Data is arranged as essentially a long sequence
  of bits that begin at one end of the tape and
  stretches to the other
• Tape backup - copy of data on hard disk stored on
  magnetic tape.

31
Storage Devices
Section C
Chapter 2
CD technology Why would I want a CD-ROM drive
in addition to a hard disk drive?

• CD-ROM
• stands for Compact Disc Read-Only Memory
• data stamped on when manufactured
• coated with clear plastic, durable
• estimated life exceeds 500 years
• inexpensive to manufacture
• ideal for distribution of large files

32
Storage Devices
Section C
Chapter 2
Whats the difference between CD-ROM and ROM
BIOS?

• They are different technologies
• ROM-BIOS (chip on the motherboard) is magnetic
• CD-ROM (optical storage device) is optical

33
Storage Devices
Section C
Chapter 2
Whats the difference between CD-ROM and ROM
BIOS?
34
Input and Output Devices
Section D
Chapter 2
Expansion slots, cards and ports How does a
computer get data from RAM to a peripheral device?

• Data Bus carries data from one component to
  another
• I/O (computer jargon for input/output) refers to
  collecting data and transporting results.
• Expansion bus - the segment of the data bus that
  transports data between RAM and peripheral devices

35
Input and Output Devices
Section D
Chapter 2
What is an expansion slot?

• Expansion slot - long, narrow socket on the
  motherboard into which you can plug an expansion
  card
• graphics card (for connecting monitor)
• modem (for transmitting data over phone or cable
  lines)
• sound card (for connecting speakers)
• Expansion card - small circuit board that
  provides computer with ability to control
  storage, input or output device
• Most microcomputers have 4 - 8 expansion slots

36
Input and Output Devices
Section D
Chapter 2
What is an expansion slot?
Click to start
37
Input and Output Devices
Section D
Chapter 2
What are the major types of expansion slots?

• The microcomputer motherboard typically has up to
  three types of expansion slots
• ISA - older technology, modems and slow devices
• PCI - for graphics, sound, video, modem or
  network cards
• AGP - for graphics cards
• Expansion cards are built for only one type of
  slot

38
Input and Output Devices
Section D
Chapter 2
What are the major types of expansion slots?
39
Input and Output Devices
Section D
Chapter 2
Do notebook computers also contain expansion
slots?

• PCMCIA slot (personal computer memory card
  international association)
• Typically a notebook only has one slot, but the
  slot can hold more than one PC card (PCMCIA
  expansion cards)

40
Input and Output Devices
Section D
Chapter 2
What is an expansion port?
Expansion port - any connector that passes data
in and out of a computer or peripheral device
41
Input and Output Devices
Section D
Chapter 2
What are the major types of expansion cables?
(Dont forget ribbon cables)
42
Input and Output Devices
Section D
Chapter 2
Whats the difference between a CRT and an LCD?

• CRT (cathode ray tube) uses gun-like mechanisms
  to direct beams of electrons toward the screen
  and activate individual dots of color that form
  an image
• LCD (liquid crystal display) produces an image by
  manipulating light within a layer of crystal
  cells
• LCDs are clearer, have low radiation emission,
  are portable, and compact
• LCDs are also more expensive than CRTs

43
Input and Output Devices
Section D
Chapter 2
Which display device produces the best image?

• Screen size is the measurement in inches from one
  corner of the screen diagonally across to the
  opposite corner.
• Viewable image size (vis) - black border that
  makes image size smaller than size specified
• Dot pitch - a measure of image clarity
• smaller dot pitch means a crisper image
• Resolution - number of pixels a monitor can
  display

44
Input and Output Devices
Section D
Chapter 2
Which display device produces the best image?

• Color depth - number of colors that can be
  displayed at one time
• Passive matrix screen - relies on timing to make
  sure the liquid crystal cells are illuminated
• Active matrix screen - updates rapidly
• essential for crisp display of animation, video
• found on newer notebooks
• SVGA - (super video graphics array) 800x600
• XGA - (extended graphics array) 1024x768

45
Input and Output Devices
Section D
Chapter 2
What features should I look for in a printer?

• Print speed (typical 10 ppm)
• measured either by pages per minute (ppm) or
  characters per second (cps)
• color vs BW
• Duty Cycle - indication of the number of pages a
  printer can be expected to print per month
• Per-copy cost
• printers require ongoing costs including
• per copy cost is the cost of printing a page with
  an average amount of text, graphics, and color
• Warranty
• cover mechanical problems

46
Input and Output Devices
Section D
Chapter 2
Whats the difference between an ink jet
printer and a solid ink printer?

• An ink jet printer is todays most popular
  printing technology.
• print head consists of a series of nozzles that
  sprays ink onto paper
• On special paper can produce photographic quality
• A laser printer uses the same technology as a
  photocopier to paint dots of light on a
  light-sensitive drum.
• higher quality than ink jet
• more expensive to buy than ink jet
• less expensive to operate than ink jet