http://www.professormesser.com/wiki/ 2010-02-07T03:37:51-05:00 http://www.professormesser.com/wiki/ http://www.professormesser.com/wiki/lib/images/favicon.ico text/html 2010-02-05T18:22:14-05:00 http://www.professormesser.com/wiki/displays:liquid_crystal_displays?rev=1265412134&do=diff Liquid Crystal Displays or LCDs use a grid of liquid crystal filled cells, each representing a pixel. In color displays, each pixel is comprised of three sub-pixels with red, green, and blue color filters. When a varying voltage is applied to each cell the crystals can show colors of varying intensities. text/html 2009-06-24T11:28:47-05:00 http://www.professormesser.com/wiki/networking:well-known_port_numbers_for_common_protocols?rev=1245857327&do=diff * FTP - Data (File Transfer Protocol - Data) : TCP Port 20 - FTP Data is used to transfer data from a server or transfer data to a server (e.g., uploading a Web page file to a server). * FTP - Control (File Transfer Protocol - Control) : TCP Port 21 - FTP Control is used to open a connection to the FTP server. text/html 2009-06-08T20:32:33-05:00 http://www.professormesser.com/wiki/start?rev=1244507553&do=diff This guide was created through the efforts of many people. It is a dynamic Wiki page that allows registered users to add, remove, or modify pages. If you have study material relative to the CompTIA A+ exam that you would like to share, please feel free to contribute. text/html 2008-12-19T01:50:49-05:00 http://www.professormesser.com/wiki/operating-systems:installation_requirements_for_windows_2000_windows_xp_and_windows_vista?rev=1229669449&do=diff Windows 2000 Professional Installation Requirements Minimum configuration Processor speed: Intel Pentium 133 MHz Memory: 64MB Free hard drive space: 650MB Network: Not required Display: VGA resolution (640 x 480) Floppy Drive: Required if using boot floppy disks CD-ROM: Required text/html 2008-12-19T01:49:57-05:00 http://www.professormesser.com/wiki/printers:the_printing_process_on_a_laser_printer?rev=1229669397&do=diff Laser Printing Process While some documentation may list the following steps in a different order, the following sequence is what CompTIA will use for the exam. * Clean - Before printing, the drum must be cleaned. * Charge - Drum is charged with a negative charge (between ~600 and ~1000 volts) to receive new images. * Write - A laser is used to write a positively charged image to the surface of the drum. * Develop - Charged image attracts toner. * Transfer - The transfer corona appl… text/html 2008-12-19T01:48:48-05:00 http://www.professormesser.com/wiki/printers:types_of_printers?rev=1229669328&do=diff Dot Matrix An impact printer that forms characters by striking a pattern, or matrix, of pins through an inked ribbon and onto a piece of paper. Ink Jet A non-impact page printer that prints by ejecting ink through the print heads and onto the paper. text/html 2008-12-19T01:47:03-05:00 http://www.professormesser.com/wiki/networking:dhcp?rev=1229669223&do=diff (The following may require editing as I'm not entirely sure) DHCP stands for Dynamic Host Configuration Protocol and is an Internet protocol. It resides in a DHCP server (which could be a computer or router) and clients that use the server. A DHCP server supplies Internet Protocol (IP) addresses when requested by client computers on a TCP/IP network that have TCP/IP configured to obtain their IP addresses automatically. A DHCP server is configured to use a range of IP addresses known as its sco… text/html 2008-12-19T01:46:11-05:00 http://www.professormesser.com/wiki/networking:wireless_802.11?rev=1229669171&do=diff IEEE 802.11 is a set of standards for wireless local area networks (WLANs). The standards encompass these: 802.11a * 5 GHz radio frequency * Up to 54 Mbps transfer * ~35 meter in-door range 802.11b * 2.4 GHz radio frequency * Up to 11 Mbps transfer * ~35 meter in-door range * Nearby devices of a similar frequency can cause interference--microwaves, cordless phones, etc. text/html 2008-12-19T01:45:23-05:00 http://www.professormesser.com/wiki/networking:ethernet?rev=1229669123&do=diff Ethernet, standardized as IEEE 802.3, is a family of frame-based networking technologies for LANs (Local Area Network). Ethernet describes the physical cabling attributes, signaling, and bandwidth characteristics. Ethernet includes: 10Base5 * Uses thick coax cable * Up to 10 Mbps transfer * Up to 500 meters cable length text/html 2008-12-19T01:43:42-05:00 http://www.professormesser.com/wiki/displays:screen_resolutions?rev=1229669022&do=diff * Video Graphics Array (VGA): 640×480 * Super Video Graphics Array (SVGA): 800×600 - 1024×768 * Extended Graphics Array (XGA): 1024×768 * Super Extended Graphics Array (SXGA): 1280×1024 * Super Extended Graphics Array Plus (SXGA+): 1400×1050 * Widescreen SXGA Plus (WSXGA+): 1680×1050 (Widescreen) * Ultra Extended Graphics Array (UXGA): 1600×1200 * Widescreen UXGA (WUXGA): 1920×1200 (Widescreen) text/html 2008-12-19T01:42:58-05:00 http://www.professormesser.com/wiki/miscellaneous:interrupt_requests_irqs?rev=1229668978&do=diff Knowledge of interrupt requests (IRQs) is not required of CompTIA A+ 2006 candidates but is still useful when working with legacy/non-PnP hardware. Interrupt requests or IRQs are physical circuits on a motherboard that allow various devices to request the attention of the CPU and exchange data and/or instructions over I/O addresses in memory, assigned to those devices. On newer hardware the operating system assigns an IRQ number to each device during the OS boot sequence (Windows uses Ntdetect.… text/html 2008-12-19T01:41:45-05:00 http://www.professormesser.com/wiki/storage:raid?rev=1229668905&do=diff RAID (Redundant Array of Independent Disks) * RAID 0 - Provides striping of file bits across other volume(s). At least 2 drives are required; no redundancy is provided (one drive failure results in data loss). * RAID 1 - Mirrors the data from one drive to another. At least 2 drives are required and 1 drive may fail without data loss.