System Unit Components

  • System Board: The system board is the personal computer component that acts as the backbone for the entire computer system.
  • Central Processing Unit (CPU): The central processing unit (CPU), sometimes called microprocessor or just processor, is the real brains of the computer and is where most of the calculations take place.
  • Memory: Memory is the personal computer component that comprises the electronic storage areas in the computer. It can be considered either volatile or non-volatile.
  • System Bus : The system bus is the main communication path between the CPU and memory.
  • Storage devices : A storage device is a system unit component, such as a hard drive, that enables users to save data for reuse at a later time, even after the personal computer is shut down and restarted.
  • Power supply is an internal computer component that converts AC power from an electrical outlet to the DC power needed by system components.
  • Adapter card is a printed circuit board that you install into a slot on the computer’s system board to expand the functionality of the computer.
  • Riser card is a board that plugs in to the system board and provides additional slots for adapter cards..

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Computer Storage Devices

The various types of storage devices used in personal computers are:

  • Floppy Disk Drives (FDD): is a personal computer storage device that reads data from, and writes data to, removable disks made of flexible Mylar plastic covered with a magnetic coating and enclosed in a stiff, protective, plastic case.
  • Hard Disk Drives (HDD) :is a personal computer storage device that uses fixed media, which means that the disk is built into the drive and the drives are not removed from the computer unless you are performing an upgrade or a repair.
  • Optical Drives: is a personal computer storage device that stores data optically, rather than magnetically.
  • Tape Drives: is a personal computer storage device that stores data magnetically on a removable tape that is enclosed in a tape cartridge.
  • Solid State Storage devices: is a personal computer storage device that stores data in special types of memory instead of on disks or tape.

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Personal Computer Connection Methods

The various PC connection methods are:

  • Ports : is a hardware connection interface on a personal computer that enables devices to be connected to the computer.
  • Personal Computer Connections : is a means by which a personal computer component is attached to other components to provide computing capabilities.
  • Serial Connections : Serial connection is a personal computer connection that transfers data one bit at a time over a single wire.
  • Parallel Connections : is a personal computer connection that transfers data eight bits at a time over eight wires and is typically used to connect a printer to a system unit.
  • Universal Serial Bus (USB) Connections : USB connection is a personal computer connection that enables you to connect multiple peripherals to a single port with high performance and minimal device configuration.
  • Infrared connection : Infrared connections require no additional wiring, and both devices come with IrDA ports as standard. However, infrared connections require line-of-sight to operate reliably, and even then performance is not acceptable for debugging. However, IrDA can be useful as a last resort technique to copy files to devices.
  • Bluetooth : Many devices feature Bluetooth wireless networking. Once paired, the smart device can connect over ActiveSync as long as it is within range of the desktop computer. Because Bluetooth is not as fast as 802.11b/g wireless, avoid using it for debugging.
  • Wireless 802.11b/g network : Wireless networking is as fast as a wired Ethernet network connection.
  • IEEE 1394 and FireWire Connections : is a personal computer connection that provides a high-speed interface for peripheral devices that are designed to use the IEEE 1394 standard.
  • Small Computer Systems Interface (SCSI) Connections : A SCSI connection is a personal computer connection that connects internal and external components to the system unit and provides for high-speed data transfer.
  • Parallel ATA (PATA) Connections : A PATA connection is a personal computer connection that provides a parallel data channel from a disk controller to the disk drives.
  • Serial ATA (SATA) Connections : A SATA connection is a personal computer connection that provides a serial data channel between the drive controller and the disk drives.

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HTTP Status Code Meaning

Type Ctrl+F to find specific code

  • 100 Continue
  • 101 Switching Protocols
  • 102 Processing
  • 200 OK
  • 201 Created
  • 202 Accepted
  • 203 Non-authoritative Information
  • 204 No Content
  • 205 Reset Content
  • 206 Partial Content
  • 207 Multi-Status
  • 208 Already Reported
  • 226 IM Used
  • 300 Multiple Choices
  • 301 Moved Permanently
  • 302 Found
  • 303 See Other
  • 304 Not Modified
  • 305 Use Proxy
  • 307 Temporary Redirect
  • 308 Permanent Redirect
  • 400 Bad Request
  • 401 Unauthorized
  • 402 Payment Required
  • 403 Forbidden
  • 404 Not Found
  • 405 Method Not Allowed
  • 406 Not Acceptable
  • 407 Proxy Authentication Required
  • 408 Request Timeout
  • 409 Conflict
  • 410 Gone
  • 411 Length Required
  • 412 Precondition Failed
  • 413 Payload Too Large
  • 414 Request-URI Too Long
  • 415 Unsupported Media Type
  • 416 Requested Range Not Satisfiable
  • 417 Expectation Failed
  • 418 I’m a teapot
  • 421 Misdirected Request
  • 422 Unprocessable Entity
  • 423 Locked
  • 424 Failed Dependency
  • 426 Upgrade Required
  • 428 Precondition Required
  • 429 Too Many Requests
  • 431 Request Header Fields Too Large
  • 451 Unavailable For Legal Reasons
  • 499 Client Closed Request
  • 500 Internal Server Error
  • 501 Not Implemented
  • 502 Bad Gateway
  • 503 Service Unavailable
  • 504 Gateway Timeout
  • 505 HTTP Version Not Supported
  • 506 Variant Also Negotiates
  • 507 Insufficient Storage
  • 508 Loop Detected
  • 510 Not Extended
  • 511 Network Authentication Required
  • 599 Network Connect Timeout Error

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Explain the applications of style sheets in web pages with coding examples

Cascading Style Sheet:

CSS is the language for describing the presentation of Web pages, including colors, layout, and fonts. It allows to adapt the presentation to different types of devices, such as large screens, small screens, or printers. CSS is independent of HTML and can be used with any XML-based markup language. The separation of HTML from CSS makes it easier to maintain sites, share style sheets across pages, and tailor pages to different environments. This is referred to as the separation of structure (or: content) from presentation.

  • CSS stands for Cascading Style Sheets
  • Styles define how to display HTML elements
  • Styles were added to HTML 4.0 to solve a problem
  • External Style Sheets can save a lot of work
  • External Style Sheets are stored in CSS files
  • Styles are normally saved in external .css files. External style sheets enable you to change the appearance and layout of all the pages in a Web site, just by editing one single file!

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