In these systems, input and output devices are located outside of the system unit. (2023)

system unit

system unit

Ch 4 The system unit

competencies

Describe the three basic types of system units.

Discuss how a computer uses binary codes to represent data in electronic form.

Describe all the main components of the system unit.

Explain the differences between the three types of memory.

Describe the five main types of bus routes.

Discuss the most common types of ports.

introduction

• Differences in microcomputer performance focus on speed, capacity, and flexibility.
• Competent end users must understand the functionality of the basic components in the system unit, including the system board, microprocessor, memory, system clock, expansion slots and cards, bus lines, ports, cables, and power supplies.
• Some terms:
• drives: are secondary storage devices used to store data, programs, and information.
• bus lines: Providing data paths connecting various system components
• Power supply unit: converts alternating current (AC) to direct current (DC) and supplies power to the system unit.
• Systems Board: connects all system components with each other.
• system unit: Contains most of the computer's electronic components.
• memory: Contains data, instructions, and information, memory boards plug into slots on the system board
• microprocessor: Controls operations and performs arithmetic and logical operations, microprocessor cartridges plug into a special slot on the system board.
• expansion cards: Allow external devices to connect to a computer and expand its capabilities, expansion cards plug into slots on the system board.
• expansion slots: Provides connectors for expansion cards on the system board.

system unit

• Thatsystem unit(akasystem cabinetorChassis) is a container that houses most of the electronic components that make up a computer system.
• Three basic types of microcomputers include:
• Desktop System Units: contain the electronic components of the system and selected secondary storage. Input and output devices such as mouse, keyboard, monitor are located outside of the system unit. It can be placed either horizontally or vertically. Vertical units are called "tower models“.
• Notebook system units: are portable and much smaller. They contain the electronic components, selected secondary storage and input devices (keyboard and pointing device). The monitor is located outside the system unit, which is attached to it with hinges.
• Personal Digital Assistant (PDA)-Systemeinheiten: smallest and designed to fit in the palm of your hand. It contains the entire computer system including electronic components, secondary storage, and input and output devices

Electronic data and instructions

• Computers only recognizeDigitalelectronic signals.
• A lot of information comes acrossanalogSignals: continuous signals that vary to represent different tones, pitches, and volumes, like our voices.
• Computers must be able to convert analog signals to digital for processing.
• Computer data and information is represented electronically with abinary, ortwo statesSystem.
• Only use binary systemsbinary,0&1.
• Any 0 or 1 is called aa little– Abbreviation for binary digit.
• Bitsare grouped into groups of eight called bitsByteto represent numbers, letters and other characters.
• EveryoneBytetypically representsa sign.

Binary Encoding Schemes

Characters are represented as a series of bits using a binary file
coding scheme. Popular schemes are:

• ASCII: American Standard Code for Information Interchange – the most widely used code for microcomputers. It usually uses one8 BitEncoding scheme, enough to handle 28 (256) different characters. An example of the letter A is 0100 0001.
• EBCDIC: Extended Binary Coded Decimal Interchange Code – anIBMStandard for large computers. It also uses8 Bit, but differs slightly from the ASCII encoding scheme, e.g. A = 1100 0001
• Unicode: a16-bit(2-byte) code to support international languages ​​such as Chinese and Japanese, which contains too many characters that 8-bit codes cannot support. It can display 216 characters (65,536 characters)

When you press a key on the keyboard, the keyboard hardware sends an electronic signal to the system unit and converts the key, e.g. B. the number 3, to the ASCII code 0011 0011.
All instructions and data must be converted to binary data before they can be executed. instructions for example3 + 5require24 Bit(8 bits x 3 characters) using the ASCII encoding scheme.

motherboard, mainboard, motherboard

The system board connects all system components and allows input and output devices to communicate with the system unit.

• Thatmotherboard, mainboard, motherboardis also known asmotherboardormotherboard.
• It is the communication medium for the entire computer system.
• Each component of the system unit is connected directly to the system board.
• It acts as a data path that allows the various components to communicate with each other.

Thatmotherboard, mainboard, motherboardis a large flat circuit board covered withsocketsand other electronic parts, including a variety ofChips:

• sockets: Providing a connection point for small specialized electronic parts called chips.
• Chips(akaSilikonchips,semiconductor, orintegrated circuits): consist of tiny circuit boards etched onto squares of sand-like material called silicon. Chips are mountedcarrier packsplugged into sockets on the system board.
• key: Provide a connection point for special cards or circuit boards.
• bus lines: Providing ways to support communication between electronic components.

microprocessor

• In a microcomputer, acentral unit(CPU) orprocessoris contained on a single chip called amicroprocessor.
• The microprocessor is often contained in a cartridge that plugs into the special slot on the system board. The microprocessor is the "brain" of the computer.

It has two basic components:

• control unit: tells the rest of the computer system how to execute a program's instructions. It routes the electronic signals between memory and ALU as well as between CPU and input and output devices.
• Arithmetic logic unit(akaAlu): performedarithmetic operations– Addition, subtraction, multiplication and division andlogical operations– Compare like equal (=), less than (<) or greater than (>).

microprocessor chips

The capacities of microprocessors differ in terms of:

• word size- the number of bits that can be accessed simultaneously by the CPU - typically 16, 32 or 64 bits. The more bits in a word, the more powerful - and the faster - the computer is. A 32-bit word machine can access 4 bytes at a time and a 64-bit word machine can access 8 bytes at a time, and therefore a 64-bit machine is faster.
• speed- how fast the microprocessor can process data and instructions - older microcomputers processed data inmicroseconds: millionths of a second. Newer systems are faster and process data & instructions in billionths of a second:nanoseconds.
• Supercomputers can process dataThe picosecond: trillionths of a second, 1,000 times faster than a microcomputer.

There are two types of microprocessor chips:

• Computing with complex instruction sets(CISC) Chips: This is the most common type of microprocessors that are made popular byIntel. These are the most popular microcomputer CPU chips sold byIntel– Pentium and Itanium andAMD– Athlon and Hammer.
• Computing with a reduced instruction set(RISK) chips: Use fewer instructions, the design is simpler and less expensive than CISC chips. Examples include the chip made by PowerPCMotorola, the alpha chip fromDEZ, SPARC chip fromSonneMicrosystems, Silicon Graph's MIPS chip.

special processors

• Smartcards: a credit card-sized plastic card with an embedded chip. They can store 80 times more information than regular credit cards. They can record personal financial and medical information in encrypted or encrypted form by protecting them with passwords or PIN numbers, hence providing strong security and privacy.
• co-processors: Special chips to improve certain arithmetic operations.
• graphics coprocessors: Handling processing for displaying and manipulating 2-D and 3-D graphics images.
• Parallel processors: Using specialized software, these are typically used in network servers and supercomputer systems.
• Visa, MasterCard and American Express have introduced their smart cards to millions of users.

memory

• Memory is a holding area for data, instructions, and information.
• Memory resides on chips that connect to the system board.

There are three known types of memory chips:

Random Access Memory (RAM)

• RAM chips contain the program instructions and data that the CPU is currently processing.
• RAM is calledin the interimorvolatileStorage since the contents are lost when the microcomputer is turned off. This is different from secondary storage, which iscontinuousornonvolatile: It retains the contents when the power is turned off, as is the case with data stored on floppy disks. It's a good idea to save your work to secondary storage very often. Data from secondary storage must be loaded into RAM before it can be used.
• Flash-RAM(akaFlash memory) is a new type of RAM that is non-volatile and can store data even when the power is off. This type of memory is more expensive and is used in digital cell phones, digital cameras, and some portable computers.
• It is important to have enough RAM.
• If your computer does not have enough RAM to store a program, you can run the program on some operating systemsvirtual memory, in which large programs are broken up into parts and stored on secondary storage, each part is then swapped into and out of secondary storage as needed.
• cache memory(aka RAM cache) is a special high-speed area of ​​memory that holds information that is used most often. Cache memory can speed up processing time for your computer.
• Other types of RAM include DRAM, SDRAM.

Read Only Memory (ROM) (aka firmware)

• Programs are built into these chips at the factory.
• ROM chips arenonvolatileand cannot be changed by the user.
• "Read only" means that the CPU can read the programs written on the ROM chip, but the computer cannot write any information or instructions to the ROM.
• ROM chips usually contain special instructions for detailed computer operations, such as instructions on how to start the computer or how to display characters on the screen.
• ROM chips are also calledFirmware.

Complementary Metal Oxide Semiconductor (CMOS)

• CMOS chips provide flexibility and expandability for a computer system. It contains important information that is needed every time you turn on your computer.
• CMOS chips typically contain 64 bytes of data, including the current date and time, RAM size, keyboard type, etc.
• CMOS chips are powered by a battery and do not lose their contents when AC power is removed, unlike RAM.
• Unlike ROM, the contents of CMOS chips can be modified to update computer system changes such as increased RAM and new hardware devices.

system clock

• The system clock resides on a small, specialized chip that generates precisely timed electrical shocks, or pulses.
• The microprocessor uses the clock beats to coordinate and synchronize all computer operations.
• Thatclock speed(akaclock frequency) is usually measured ingigahertz, or billions of beats per second.

expansion slots and cards

• Computers are designed based on various "architectures".
• Aclosed architecturemeans that you generally cannot add new devices.
• Aopen architectureYou can expand the system by providing slots on the system board that accept optional devices called expansion cards.
• Expansion slots offer an open architecture.
• expansion cardsare also mentionedbreadboards, controller cards, adapter cards and interface cards. Some of the most common cards are:
• graphics cards(akagraphics cards) Connect the system board to the computer's monitor to convert the internal electronic signals into video signals for display on the monitor.
• sound cardsAccept audio input from a microphone and convert it into a form that can be processed by the computer and vice versa.
• modem cards(akainternal Modems) allow computers to communicate with each other by converting electrical signals within the system unit into electrical signals that can be transmitted over telephone lines and other types of connections.
• network interface cards(NICs akanetwork adapter cards) connect a computer to one or more other computers forming a network in which users can share data, programs and hardware, e.g. an Ethernet network
• TV tuner cards(also known as TV cards, VCR cards, or video capture cards) allow you to watch TV and record video signals on your computer.
• Plug-and-Playis a set of hardware and software standards, developed in part by Intel and Microsoft, to create operating systems, processing units, expansion cards, and other devices that automatically configure themselves to work with your computer.
• PC cards(also known as PCMCIA Personal Computer Memory Card International Association cards) are credit card-sized adapters that connect portable computers to various external devices, such as a PCMCIA Ethernet card.

Bus routes (also known as data bus or bus)

• The bus connects the parts of the CPU together and also connects the CPU to various other components on the system board.
• The number of bits that can be transmitted over the bus is called theBusbreite.
• The larger the bus width, the higher the processing speed.
• Typical bus widths are 32 or 64 bits.
• A system unit has more than one bus line type. The main bus lines are:
• ISA-Bus (Industriestandardarchitektur).: Originally an 8-bit bus developed for the first IBM PCs. Now it's a 16-bit bus and still found on some microcomputers, although slow.
• PCI-Bus (Peripheral Component Interconnect).: Originally designed for graphical user interface video requirements, a high-speed 32-bit or 64-bit bus that is over 20 times faster than the older ISA buses.
• Accelerated GraphicsPort (AGP)-Bus: more than twice as fast as PCI buses. Widely used for graphics performance acceleration, 3D animation and video data transmission.
• Universal Serial Bus (USB)combines with a PCI bus on the system board to support multiple external devices without using expansion cards or slots. USB buses are commonly used to support high-speed scanners, printers, and video capture devices.
• High Performance Serial Bus (HPSB)(akaFireWire-Bus) operate similarly to USB buses, but at higher speeds, and are typically used to connect digital camcorders.

ports

• AHarboris a socket for external devices to be connected to the system unit.

Standardports

• Serial Ports: Send data to connect a mouse, keyboard, modem, etcbit by bit. Good for sending data over a longer distance.
• Parallele Ports: For connecting external devices that need to send or receive large amounts of data over a short distance, such as B. Printer. Sends eight bits of data simultaneously over eight parallel wires.
• USB ports: gradual replacement of serial and parallel ports. They are faster and multiple devices can be connected to the system unit via a USB port.
• FireWire-Ports(akaHPSB): are faster than USB ports and are typically used to connect video devices to a computer.

Cable

• Cableare the “lines” to connect external devices to the system unit via the ports.

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system unit

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system unit

What system input and output devices are external to the system unit?

Input and output devices such asmouse, keyboard and monitorare outside of the system unit.

Which of the following is outside of the system unit?

Components and Select Secondary Storage Devices. Input and output devices such asmouse, keyboard and monitorare outside of the system unit. This type of system unit is designed to be placed either horizontally or vertically.

Which of the following devices can be used to connect multiple devices to the system unit and are widely used?

USB port (Universal Serial Bus).Most desktop computers have multiple USB ports. These can be used to connect almost any type of device including mice, keyboards, printers and digital cameras.

What kind of keyboard uses a touchscreen as an input device?

If you have a PC with a touch screen, theTouch keyboardyou can enter text by tapping your stylus or your fingertip on a keyboard that appears on your screen.