The Components of the System Unit
Chapter 4 The Components of the System Unit
The System Unit • Box-like case that contains computer’s electronic components • Sometimes called the chassis
What are common components inside the system unit? • Processor • Memory module • Expansion cards o Sound card o Modem card o Video card o Network interface card • Ports and Connectors
What is the motherboard? • Main circuit board in system unit • Contains chips, integrated circuits, and transistors • Also called system board
What chip packages are available? • single edge contact (SEC) cartridge • dual inline package (DIP) • flip chip-PGA (FC-PGA) package • pin grid array (PGA
Central Processing Unit
What is the central processing unit (CPU) ? • Interprets and carries out basic instructions that operate a computer • Also called the processor
What are the components of the CPU? • Control Unit • Arithmetic/Logic Unit (ALU)
What is the control unit? • Directs and coordinates operations in computer • Control unit repeats four basic operations: • Fetch - obtain program instruction or data item from memory • Decode - translate instruction into commands • Execute - carry out command • Store - write result to memory
What is a machine cycle? • Four operations of the CPU comprise a machine cycle • Also called instruction cycle • Instruction time (i-time) - time taken to fetch and decode • Execution time (e-time) - time taken to execute and store
An example of a machine cycle • Student enters math problem (100 x 52) into computer’s memory • Result in memory displays on monitor’s screen
How is the CPU’s speed measured? • According to how many millions of instructions per second (MIPS) it can process
What are two designs used for the CPU? • CISC (complex instruction set computing) o Supports large number of instructions o CPU executes complex instructions more
The System Unit • Box-like case that contains computer’s electronic components • Sometimes called the chassis
What are common components inside the system unit? • Processor • Memory module • Expansion cards o Sound card o Modem card o Video card o Network interface card • Ports and Connectors
What is the motherboard? • Main circuit board in system unit • Contains chips, integrated circuits, and transistors • Also called system board
What chip packages are available? • single edge contact (SEC) cartridge • dual inline package (DIP) • flip chip-PGA (FC-PGA) package • pin grid array (PGA
Central Processing Unit
What is the central processing unit (CPU) ? • Interprets and carries out basic instructions that operate a computer • Also called the processor
What are the components of the CPU? • Control Unit • Arithmetic/Logic Unit (ALU)
What is the control unit? • Directs and coordinates operations in computer • Control unit repeats four basic operations: • Fetch - obtain program instruction or data item from memory • Decode - translate instruction into commands • Execute - carry out command • Store - write result to memory
What is a machine cycle? • Four operations of the CPU comprise a machine cycle • Also called instruction cycle • Instruction time (i-time) - time taken to fetch and decode • Execution time (e-time) - time taken to execute and store
An example of a machine cycle • Student enters math problem (100 x 52) into computer’s memory • Result in memory displays on monitor’s screen
How is the CPU’s speed measured? • According to how many millions of instructions per second (MIPS) it can process
What are two designs used for the CPU? • CISC (complex instruction set computing) o Supports large number of instructions o CPU executes complex instructions more