Holds components in a cool, clean, safe environment and shields from radio frequencies
Computer encasement configurations
Desktop model
Tower model
Desktop model
Horizontal encasement, takes up desk space, less room for expansion
Tower model
Vertical encasement, easily placed off work surface, more room for expansion
Motherboard components
CPU
BIOS
Bus
Memory
Ports
CMOS
Central processing unit (CPU)
Also known as microprocessor, the brain of the computer
CPU
Manufactured by AMD and Intel
Reads data from storage, manipulates data, moves data to storage or external devices
CPU component parts
Control unit
Arithmetic-logic unit
Registers
Primary storage
Control unit
Accesses program instructions, decodes instructions, controls data flow
Arithmetic-logic unit
Performs computations and comparisons on data
Registers
High speed storage areas that hold data and instructions
Primary storage (main memory)
Stores instructions from programs and data to be processed
Machine instruction cycle
1. Instruction fetched from primary storage by control unit
2. Control unit decodes instruction
3. ALU receives data and instruction, performs calculation or comparison
4. Result stored in primary storage
Computer performance
Measured by machine instruction cycles per second
Affected by clock speed, word length, bus width, line width
Microprocessor evolution
Miniaturization of transistors
Decreasing distance between transistors (decreasing line width)
Improved conductivity
Improved instruction sets
Basic input/output system (BIOS)
Contains instructions for boot-up process, runs start-up diagnostics, oversees basic functions after boot-up, intermediary between OS and hardware
Bus
Series of connections, controllers, and chips that creates the information highway of the computer. Most modern PCs have a PCI bus.
BIOS
Basic Input/Output System - oversees the basic functions of receiving and interpreting signals from the keyboard and interchanging information with various ports, intermediary between the operating system and the hardware
Bus
Series of connections, controllers, and chips that creates the information highway of the computer, connects the microprocessor, the system memory, and various peripherals
Buses found within the computer
PCI (Peripheral Component Interconnect) bus
SCSI (Small Computer System Interface) connections
AGP (Accelerated Graphics Port) for video adapters
USB (Universal Serial Bus) for a variety of devices
Primary Storage (Main Memory)
Temporary storage area that holds information being worked with, application software, and operating system software, increasing memory capacity increases system performance
Types of Primary Storage
Registers
Random Access Memory (RAM)
Cache Memory
Read-only Memory (ROM)
Secondary Storage
Non-volatile storage of data and instructions, huge storage capacity, cheaper than Primary Storage, slower than Primary Storage, includes magnetic and optical storage media
Secondary Storage Types
Magnetic tape
Magnetic Disk (Floppy, Hard disk, Zip drive)
Memory Cards and Cartridges
Optical (CD-ROM, CD-RW, DVD, FMD-ROM)
Enterprise Storage Systems
Provide coordinated, secure, managed storage for all enterprise data, includes Redundant Array of Independent Disks (RAID), Storage Area Network, Network-Attached Storage, and Storage Service Providers