1. Computer Hardware Chapter 5

2. Motherboard 1: Ports 3: Expansion slots 6: Central processing unit

3. Motherboard 8: RAM sockets 12: ROM BIOS Data bus: moves data

4. RAM Random access memory Blackboard: constantly creating info then erasing Volatile Capacity measured in megabytes –Holds data to be processed –Holds instructions –Holds results until stored Access time: nanoseconds Big impact on performance of system

5. Virtual Memory Operating system uses portion of hard drive as extension of RAM Can handle programs which require more RAM Slows performance

6. Central Processing Unit Gets data and instructions from RAM Processes data Sends results to RAM

7. Central Processing Unit Performance Clock speed measured in MHz –Heart beat: how fast can instructions be executed –New chips up to 1,000 MHz Cache memory –Rapid access to frequently used data First look for data in cache memory –Level 1: on CPU –Level 2: separate chip Fast chip without adequate RAM will be slow

8. ROM Read Only Memory Not volatile, permanent Generally can not change instructions BIOS: tells CPU where to find operating system and determines how peripherals will share resources

9. Boot process Power up: power light is on Start boot program: execute instructions in ROM Power-On Self-Test: checks monitor, RAM, keyboard, disk drives

10. Boot process continued Load operating system into RAM: –Will look in a: drive if it contains disk Check configuration and setup files Ready

11. Plug and Play Computer system automatically detects and configures expansion cards and devices Connect a new device to system such as a new printer Restart computer Operating system finds device and installs drivers, if available Greatly simplifies process of adding expansion cards and peripherals

12. CD-R Compact-disk recordable –Can write data on it but can not erase and rewrite –Uses Music Back up data –Hold equivalent of 500 floppies CD-RW –Compact-disk rewritable Can erase and rewrite data