The Components of the System Unit PDF

**The Components of the System Unit** **Objectives Overview** - Differentiate among various styles of system units on desktop computers, notebook computers, and mobile devices - Identify chips, adapter cards, and other components of a motherboard - Describe the control unit and arithme...

**The Components of the System Unit** **Objectives Overview** - Differentiate among various styles of system units on desktop computers, notebook computers, and mobile devices - Identify chips, adapter cards, and other components of a motherboard - Describe the control unit and arithmetic logic unit components of a processor, and explain the four steps in a machine cycle - Identify characteristics of various personal computer processors on the market today, and describe the ways processors are cooled - Explain how program instructions transfer in and out of memory - Differentiate among the various types of memory - Describe the purpose and types of expansion slots and adapter cards, and differentiate among slots for various removable flash memory devices - Differentiate between a port and a connector, and explain the differences among a USB port, FireWire port, Bluetooth port, SCSI port, eSATA port, IrDA port, serial port, and MIDI port - Describe the types of buses in a computer - Explain the purpose of a power supply and describe how it keeps cool **The System Unit** - The **system unit** is a case that contains electronic components of the computer used to process data - **The inside of the system unit on a desktop personal computer includes:** - Drive bay(s) - Power supply - Sound card - Video card - Processor - Memory - The **motherboard** is the main circuit board of the system unit - A computer **chip** contains integrated circuits  **Processor** - The **processor**, also called the **central processing unit** (**CPU**), interprets and carries out the basic instructions that operate a computer - Contain a control unit and an arithmetic logic unit (ALU) - **Multi-core processor** - **Dual-core processor** - **Quad-core processor** - The **control unit** is the component of the processor that directs and coordinates most of the operations in the computer - The **arithmetic logic unit** (ALU) performs arithmetic, comparison, and other operations - For every instruction, a processor repeats a set of four basic operations, which comprise a machine cycle - Most current personal computers support pipelining - Processor begins fetching a second instruction before it completes the machine cycle for the first instruction - The processor contains registers, that temporarily hold data and instructions - The **system clock** controls the timing of all computer operations - The pace of the system clock is called the **clock speed**, and is measured in **gigahertz** (**GHz**) - The leading manufacturers of personal computer processor chips are Intel and AMD  - A processor chip generates heat that could cause the chip to burn up - Require additional cooling - Heat sinks - Liquid cooling technology  - Parallel processing uses multiple processors simultaneously to execute a single program or task - Massively parallel processing involves hundreds or thousands of processors - ASCII (American Standard Code for Information Interchange)  **Memory** - **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 - Each location in memory has an address - Memory size is measured in **kilobytes** (**KB** or **K**), **megabytes** (**MB**), **gigabytes** (**GB**), or **terabytes** (**TB**) - The system unit contains two types of memory: - Loses its contents when power is turned off - Example includes **RAM** **Nonvolatile memory** - Does not lose contents when power is removed - Examples include ROM, flash memory - Three basic types of RAM chips exist: - Dynamic RAM (DRAM) - Static RAM (SRAM) - Magnetoresistive RAM (MRAM) - RAM chips usually reside on a **memory module** and are inserted into **memory slots** - The amount of RAM necessary in a computer often depends on the types of software you plan to use  - **Memory cache** speeds the processes of the computer because it stores frequently used instructions and data - **Read-only memory** (**ROM**) refers to memory chips storing permanent data and instructions - **Firmware** - A PROM (programmable read-only memory) chip is a blank ROM chip that can be written to permanently - EEPROM can be erased - **Flash memory** can be erased electronically and rewritten - **CMOS** technology provides high speeds and consumes little power  - **Access time** is the amount of time it takes the processor to read from memory - Measured in **nanoseconds**  **Expansion Slots and Adapter Cards** - An **expansion slot** is a socket on the motherboard that can hold an adapter card - An **adapter card** enhances functions of a component of the system unit and/or provides connections to **peripherals** - **Sound card** and **video card** - With **Plug and Play**, the computer automatically can configure adapter cards and other peripherals as you install them - Removable flash memory includes: - **Memory cards**, USB flash drives, **Ports and Connectors** - A **port** is the point at which a peripheral attaches to or communicates with a system unit (sometimes referred to as a **jack**) - A **connector** joins a cable to a port - On a notebook computer, the ports are on the back, front, and/or sides - Other types of ports include: - **Firewire port** - **Bluetooth** **port** - **SCSI port** - **eSATA port** - **IrDA port** - **Serial port** - **MIDI port**  **A Bluetooth wireless port adapter converts** **a USB port into a Bluetooth port** **A smart phone might communicate** **with a notebook computer using an IrDA port** **Buses** - **Expansion slots connect to expansion buses** - **Common types of expansion buses include:** - **PCI bus** - **PCI Express bus** - **Accelerated Graphics Port** - **USB and FireWire bus** - **PC Card bus** - **A bay is an opening inside the system unit** - **A drive bay typically holds disk drives** - **The power supply converts the wall outlet AC power into DC power** - **Some external peripherals have an AC adapter,** - **which is an external power supply** **Putting It All Together** **Home** - **Intel Core 2 Duo or Intel Celeron Dual Core or AMD Sempron** - **Minimum RAM: 2 GB** **Small Office/Home Office** - **Intel Core 2 Quad or Intel Core 2 Extreme or AMD Athlon FX or AMD Athlon X2 Dual-Code** - **Minimum RAM: 4 GB** **Mobile** - **Intel Core 2 Extreme or AMD Turion X2** - **Minimum RAM: 2 GB** **Power** - **Intel Itanium 2 or AMD Quad Core Opteron or Intel Quad Core Xeon or Sun UltraSPARC T2** - **Minimum RAM: 8 GB** **Enterprise** - **Intel Core 2 Quad or Intel Core 2 Extreme or AMD Athlon FX or AMD Athlon X2 Dual-Core** - **Minimum RAM: 4 GB**