1. Processor
1.1. The processor, also called the central processing unit (CPU), interprets and carries out the basic instructions that operate a computer
1.2. The control unit is the component of the processor that directs and coordinates most of the operations in the computer
1.3. The arithmetic logic unit (ALU) performs arithmetic, comparison, and other operations
1.4. For every instruction, a processor repeats a set of four basic operations, which comprise a machine cycle
1.5. Most current personal computers support pipelining
1.6. The leading manufacturers of personal computer processor chips are Intel and AMD
1.7. Determine how you plan to use a new computer before selecting a processor
1.8. A processor chip generates heat that could cause the chip to burn up
1.9. Require additional cooling
1.10. Parallel processing uses multiple processors simultaneously to execute a single program or task
2. Buses
2.1. A bus allows the various devices both inside and attached to the system unit to communicate with each other
2.1.1. Data bus
2.1.2. Address bus
2.2. Word size is the number of bits the processor can interpret and execute at a given time
2.3. Expansion slots connect to expansion buses
2.4. Common types of expansion buses include
2.4.1. PCI bus
2.4.2. PCI Express bus
2.4.3. Accelerated Graphics Port
2.4.4. USB and FireWire bus
2.4.5. PC Card bus
3. Power Supply
3.1. The power supply converts the wall outlet AC power into DC power
3.2. Some external peripherals have an AC adapter, which is an external power supply
4. Keeping Your Computer or Mobile Device Clean
4.1. Clean your computer or mobile device once or twice a year
4.2. Turn off and unplug your computer or mobile device before cleaning it
4.3. Use compressed air to blow away dust
4.4. Use an antistatic wipe to clean the exterior of the case and a cleaning solution and soft cloth to clean the screen
5. Memory
5.1. Memory consists of electronic components that store instructions waiting to be executed by the processor, data needed by those instructions, and the results of processing the data
5.2. Stores three basic categories of items
5.2.1. The operating system and other system software
5.2.2. Application programs
5.2.3. Data being processed and the resulting information
5.3. Each location in memory has an address
5.4. Memory size is measured in kilobytes (KB or K), megabytes (MB), gigabytes (GB), or terabytes (TB)
5.5. The system unit contains two types of memory
5.5.1. Volatile memory
5.5.1.1. Loses its contents when power is turned off
5.5.1.2. Example includes RAM
5.5.2. Nonvolatile memory
5.5.2.1. Does not lose contents when power is removed
5.5.2.2. Examples include ROM, flash memory, and CMOS
5.6. Three basic types of RAM chips exist
5.6.1. Dynamic RAM (DRAM)
5.6.2. Static RAM (SRAM)
5.6.3. Magnetoresistive RAM (MRAM)
5.7. RAM chips usually reside on a memory module and are inserted into memory slots
5.8. The amount of RAM necessary in a computer often depends on the types of software you plan to use
5.9. Memory cache speeds the processes of the computer because it stores frequently used instructions and data
5.10. Flash memory can be erased electronically and rewritten
5.10.1. CMOS technology provides high speeds and consumes little power
5.11. Access time is the amount of time it takes the processor to read from memory
5.11.1. Measured in nanoseconds
6. The system unit
6.1. The system unit is a case that contains electronic components of the computer used to process data
6.2. The inside of the system unit on a desktop personal computer includes
6.2.1. Drive bay
6.2.2. Power supply
6.2.3. Sound card
6.2.4. Video card
6.2.5. Processor
6.2.6. Memory
6.3. The motherboard is the main circuit board of the system unit
6.3.1. A computer chip contains integrated circuits
7. Data Representation
7.1. Most computers are digital
7.2. The binary system uses two unique digits (0 and 1)
7.3. ASCII (American Standard Code for Information Interchange) is the most widely used coding scheme to represent data
8. Expansion Slots and Adapter Cards
8.1. An expansion slot is a socket on the motherboard that can hold an adapter card
8.2. An adapter card enhances functions of a component of the system unit and/or provides connections to peripherals
8.2.1. Sound card and video card
8.3. With Plug and Play, the computer automatically can configure adapter cards and other peripherals as you install them
8.4. Removable flash memory includes
8.4.1. Memory cards, USB flash drives, and PC Cards/ExpressCard modules
9. Ports and Connectors
9.1. A port is the point at which a peripheral attaches to or communicates with a system unit (sometimes referred to as a jack)
9.2. A connector joins a cable to a port
9.3. On a notebook computer, the ports are on the back, front, and/or sides
9.4. A USB port can connect up to 127 different peripherals together with a single connector
9.4.1. You can attach multiple peripherals using a single USB port with a USB hub
9.5. Other types of ports include
9.5.1. Firewire port
9.5.2. Bluetooth port
9.5.3. SCSI port
9.5.4. eSATA port
9.5.5. IrDA port
9.5.6. Serial port
9.5.7. MIDI port
10. Bays
10.1. A bay is an opening inside the system unit in which you can install additional equipment
10.1.1. A drive bay typically holds disk drives