chapter 4: system unit1 chapter 4 the components of the system unit system unit: case that contains...
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Chapter 4: System Unit 1
Chapter 4
The Components of the System Unit System unit: Case that contains
electronic componentspower supply
ports
drive bays
processor
memory
sound card
video cardmodem cardnetwork card
Chapter 4: System Unit 2
Motherboard
p. 128 Fig. 4-3 Next
Main circuit board in system unit
Contains adapter cards, processor chips, andmemory chips
processor chipadapter cards
memory chips
memory slots
motherboard
Expansionslots for adapter cards
Chapter 4: System Unit 3
ProcessorProcessor
Control Control UnitUnit
Arithmetic Arithmetic Logic Unit (ALU)Logic Unit (ALU)
Arithmetic Arithmetic Logic Unit (ALU)Logic Unit (ALU)
Processor CPU Interprets and performs basic instructions Control unit: coordinates operations ALU: performs math functions
p. 128 Fig. 4-4 Next
InputInputDevicesDevices
StorageStorageDevicesDevices
OutputOutputDevicesDevicesMemoryMemoryDataData InformationInformation
InstructionsInstructionsDataData
InformatioInformationn
InstructionsInstructionsDataData
InformatioInformationn
Control Control UnitUnit
Chapter 4: System Unit 4
System Clock
p. 130 Next
Pace of system Pace of system clock is clock is clock speedclock speed
Most clock speeds are Most clock speeds are in the gigahertz (GHz) in the gigahertz (GHz)
range (1 GHz = one range (1 GHz = one billion ticks of system billion ticks of system
clock per second)clock per second)
Controls timing of all computer operations Generates regular electronic pulses that set operating pace
Chapter 4: System Unit 5
Processor
Faster processor, more expensive
p. 131 Next
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Chapter 4: System Unit 6
Data Representation
How do computers represent data?
p. 132 Fig. 4-6 Next
Recognize only two discrete states: on or off
Use a binary system to recognize two states
Bytes: eight bits
Chapter 4: System Unit 7
Data Representation
What is a byte?
p. 132 Fig. 4-7 Next
Eight bits grouped together as a unit Provides enough different combinations of 0s and 1s
to represent 256 individual characters
Chapter 4: System Unit 8
Data RepresentationWhat are three popular coding systems to represent data?
p. 132 Fig. 4-8 Next
ASCII— personal computers EBCDIC—mainframes
ASCII Symbol EBCDIC
00110000 0 11110000
00110001 1 11110001
00110010 2 11110010
00110011 3 11110011
Chapter 4: System Unit 9
Memory
What is memory?
p. 134 Fig. 4-10 Next
Electronic components store instructions, data, and results
Consists of chips on motherboard
Each byte stored in unique location called an address
Seat #2B4 Seat #2B3
Chapter 4: System Unit 10
Memory
How is memory measured? By number of bytes available for storage
p. 134 Fig. 4-11 Next
Term Abbreviation Approximate Size
Kilobyte KB or K 1 thousand bytes
Megabyte MB 1 million bytes
Gigabyte GB 1 billion bytes
Terabyte TB 1 trillion bytes
Chapter 4: System Unit 11
Memory
What is random access memory (RAM)?
p. 135 Next
The more RAM a The more RAM a computer has, the computer has, the faster it respondsfaster it responds
Most RAM is Most RAM is volatile, it is lost volatile, it is lost when computer’s when computer’s
power is power is turned offturned off
Memory chips that can be Memory chips that can be read from and written read from and written
to by processorto by processor
Click to view Web Link,click Chapter 4, Click Web Linkfrom left navigation, then click RAM below Chapter 4
Chapter 4: System Unit 12
Memory
p. 136 Fig. 4-14 Next
How much RAM does an application require?
Software package indicates RAM requirements
For optimal performance, need more than minimum specifications
System RequirementsWindows® XP Home Edition/Professional• Intel Pentium processor at 233MHZ or higher• AMD K6 (Athlon Duron Family processor at 233MHZ or higher• 64 MB of RAM
Chapter 4: System Unit 13
Memory What is cache? Helps speed computer processes by storing
frequently used instructions and data L1 cache built into processor L2 cache slower but has larger capacity
p. 137 Next
Chapter 4: System Unit 14
Memory
What is read-only memory (ROM)?
p. 137 Next
Memory chips that store Memory chips that store permanent data permanent data and instructionsand instructions
The data on most ROMThe data on most ROMchips cannot be modifiedchips cannot be modified
Chapter 4: System Unit 15
Memory
What is flash memory?’ Nonvolatile memory that can be
erased electronically and reprogrammed
p. 137 Fig. 4-15 Next
Click to view Web Link,click Chapter 4, Click Web Linkfrom left navigation, then click Flash Memory below Chapter 4
Chapter 4: System Unit 16
Memory
What is CMOS?
p. 139 Next
Uses battery power to retain
information when other power is
turned off
Stores date, time, and
computer’s startup
information
Chapter 4: System Unit 17
Expansion Slots and Adapter Cards What is an expansion slot?
p. 140 Fig. 4-19 Next
An opening, or socket, on the motherboard that can hold an adapter card
Chapter 4: System Unit 18
Ports and Connectors
What is a serial port?
p. 142 Fig. 4-23 Next
Transmits one bit of data at a time
Connects slow-speed devices, such as mouse, keyboard, modem
Chapter 4: System Unit 19
Ports and Connectors
What is a parallel port?
p. 142 Fig. 4-24 Next
Connects devices that can transfer more than one bit at a time, such as a printer
Chapter 4: System Unit 20
Can be used to attach
multiple peripherals
Can be used to attach
multiple peripherals
PCs typically have four to eight USB ports
on front or back of the system unit
PCs typically have four to eight USB ports
on front or back of the system unit
Ports and Connectors
What are USB ports?
p. 142 Next
Latest version is calledUSB 2.0
Latest version is calledUSB 2.0
USB (universal serial bus) portUSB (universal serial bus) port
Chapter 4: System Unit 21
Buses
What is a bus? Channel allows
devices to communicate with each other
Connects processor and RAM
p. 144 Fig. 4-25 Next
Click to view Web Link,click Chapter 4, Click Web Linkfrom left navigation, then click Buses below Chapter 4
Access times…
RAM, hard drive, floppy