computer hardware processing and internal memory
Post on 20-Dec-2015
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CPU - Central Processing Unit
Parts of the CPU CU - Control Unit ALU - Arithmetic/Logic Unit registers internal bus
Also referred to as the microprocessor
Control Unit
part of the CPU that coordinates the operation of the computer
manages the flow of data converts instructions into
commands that the computer can understand
Arithmetic Logic Unit
Performs the actual processing by performing arithmetic and logic operations on the data
Registers
special high speed storage locations within the CPU instruction register address register storage register accumulator
Memory (RAM)
The section of the computer that holds: data and program instructions
awaiting processing intermediate processing results processed output
Processing All program instructions are converted
to binary instructions called machine language.
The processing of a single machine language instruction is accomplished in a four step machine cycle
The system clock synchronizes the machine cycle measured in Megahertz (MHz) 1 MHz is 1 million clock cycles per second
Machine Cycle
Instruction cycle (I-cycle) The control unit fetches from memory the next
command to be executed. The control unit d e c o d e s the command into an
instruction that the ALU can process. CU Execution cycle (E-cycle)
The control unit retrieves the needed data from memory and commands the ALU to e x e c u t e the required instruction
The control unit stores the result in memory.
Random Access Memory (Main Memory) used to store programs and data
on which the computer is currently working
measured in megabytes on PC’s volatile memory SIMM, DIMM DRAM, SDRAM
Cache Memory
A storage area, where the computer stores the most recently accessed data.
external cache internal cache
level 2 cache (L2 cache) SRAM
Read Only Memory
a software-in-hardware module that can be read but not written on
nonvolatile memory important pieces of system
software are stored in ROM
System Bus
Communication system for the computer
a set of wires etched into the system board (motherboard)
Types of System Buses internal bus - on the microprocessor data bus - links the CPU to RAM expansion bus - extends the data bus to
establish links with peripherals ISA, EISA
local bus - handle the most time critical busing operations (display, storage, network) PCI
Add in Boards (Cards) Customization of computer card-like pieces of hardware that contain
the circuitry to perform specific functions Variety of brands and functions
graphics adapter fax/modem boardsound card network card
plug into expansion slots
Ports sockets that allow you to plug in external
hardware devices parallel
25 holes printers, tape drives
serial (com ports) 9 or 25 pins connects low speed peripherals such as
scanners and external modems Universal Serial Bus (USB)
mouse port, keyboard port
Increasing Computer Speed increase clock speed increase word size add cache, more RAM packing circuits closer together symmetric multiprocessing RISC architecture pipelining instructions
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