Sunday, June 26, 2011


- Modulation is the addition of information to an electronic or optical signal carrier.

- Modulation can be applied to direct current mainly by turning it on and off, to alternating current, and to optical signals.


- Demodulation is the act of extracting the original information-bearing signal from a modulated carrier wave.

- A demodulator is an electronic circuit or computer program in a software defined radio that is used to recover the information content from the modulated carrier wave.

- Bandwidth, the width of the non-zero terms around the diagonal of a matrix.
- Bandwidth or analog bandwidth, frequency bandwidth or radio bandwidth is a measure of the width of a range of frequencies, measured in hertz.
- Bandwidth in computing or digital bandwidth is a rate of data transfer, bit rate or throughput, measured in bits     per second.  - Network Administrator is a person who manages a local area communications network or wide area network for an organization.


- TCP/IP stand for Transmission Control Protocol/Internet Protocol.
- It is the basic communication language or protocol of the Internet. It can also be used as a communications protocol in a private network either an intranet or an extranet.
- TCP/IP is a two-layer program.
- TCP/IP uses the server model of communication in which a computer user requests and is provided a service  by another computer in the network.
- TCP/IP communication is primarily point-to-point, meaning each communication is from one point in the network to another point or host computer.


- Node is a connection point, either a redistribution point or an end point for data transmissions.
-  A node has programmed or engineered capability to recognize and process or forward transmissions to other  nodes.


- Client is the requesting program or user in a clinent or server relationship.
- The user of a Web browser is effectively making client requests for pages from servers all over the Web.
- The browser itself is a client in its relationship with the computer that is getting and returning the requested HTML file.


- Server is the relationship between two computer programs in which one program, makes a service request from another program, the server, which fulfills the request.
- The server model has become one of the central ideas of network computing.
- In the usual client/server model, one server, sometimes called a daemon, is activated, awaits client requests.

Network Operating Systems

- Operating system (OS) is software that consisting of programs and data, that runs on computers, manages computer hardware resources, and provides common services for execution of various application software.
- This is the most important type of system software in a computer system.
- Without an operating system, a user cannot run an application program on their computer, unless the application program is self booting.

Network Administrator

- It's include network security, installing new hardware and applications, monitoring software upgrades.
- Daily activity, enforcing licensing agreements, developing a storage management program and providing for routine backups, not to mention ensuring that it is up and running all the time.

Friday, June 24, 2011

Input and Output

Ergonomic Keyboard
- A "fixed-split keyboard" is a single board, with the keys separated into two or three groups, allowing the user to type at a different angle than the typical straight keyboard.
- An "adjustable split keyboard" has the keyboard split into several independent pieces, so the angle between them can be easily changed. Either of these types of keyboards may include elevated sections at various angles.

Inkjet Printer
- An inkjet printer is a computer peripheral that produces hard copy by spraying ink onto paper. 
- A typical inkjet printer can produce copy with a resolution of at least 300 dots per inch.
- Some inkjet printers can make full color hard copies at 600 dpi or more. 
- Many models include other devices such as a scanner , photocopier , and dedicated fax machine along with the printer in a single box.
- A printer that propels droplets of ink directly onto the medium.

Laser Printer
- A laser printer is a printer that uses a focused beam or light to transfer text and images onto paper. 
- Though contrary to popular belief, the laser does not actually burn the images onto the paper. Instead, as paper passes through the printer, the laser beam fires at the surface of a cylindrical drum called a photoreceptor.
-  Laser printers do not use ink, they have less image smearing problems than inkjet printers and are able to print pages faster.
- While laser printers and toner cartridges typically cost more than inkjet printers and ink cartridges, most laser toner cartridges last several times longer than ink cartridges, which makes their cost per page about equal. 
- Laser printers typically have a resolution of 600 dpi (dots per inch) or higher.

Magnetic-ink character recognition
-  A character recognition technology used primarily by the banking industry to facilitate the processing of cheques.
-  The technology allows computers to read information (such as account numbers) off printed documents. 
- Unlike barcodes or similar technologies, however, MICR codes can be easily read by humans.
- MICR characters are printed in special typefaces with a magnetic ink or toner, usually containing iron oxide.

Optical- Mark Recognition
OMR Software is a computer software application that makes OMR possible on a desktop computer by using an Image scanner to process surveys, tests, attendance sheets, checklists, and other plain-paper forms printed on a laser printer.
- OMR Software users design their own mark-sense forms with a word processor or built-in form editor and print them locally on a laser printer saving themselves thousands of dollars on large numbers of forms.
-OMR is generally distinguished from optical character recognition (OCR) by the fact that a complicated pattern recognition engine is not required.
-One of the most familiar applications of optical mark recognition is the use of #2 (HB in Europe) pencil bubble optical answer sheets in multiple choice question examinations. Students mark their answers, or other personal information, by darkening circles marked on a pre-printed sheet. 

Optical-Character Recognition
- OCR (optical character recognition) is the recognition of printed or written text characters by a computer. 
- This involves photoscanning of the text character-by-character, analysis of the scanned-in image, and then translation of the character image into character codes, such as ASCII, commonly used in data processing.
- In OCR processing, the scanned-in image or bitmap is analyzed for light and dark areas in order to identify each alphabetic letter or numeric digit. 
- OCR is being used by libraries to digitize and preserve their holdings. OCR is also used to process checks and credit card slips and sort the mail.

Wednesday, June 15, 2011

Secondary Storage

Disk Caching
-A mechanism for improving the time it takes to read from or write to a hard disk. 
-Today, the disk cache is usually included as part of the hard disk. 
-A disk cache can also be a specified portion of random access memory (RAM). 
-The disk cache holds data that has recently been read and, in some cases, adjacent data areas that are likely to be accessed next. 

File Compression
-File compression software can accept one or more related files, combine them and reduce their size to make them more suitable for storage or transmission.
-Archiving is the term generally used when compressing files for storage, but the idea is the same as for file transfer.
-File compression eliminates data redundancy, using an algorithm that locates repeating patterns of the binary numbers zero (0) and one (1). 
-The more repeating patterns compression software can find and eliminate, the greater the compression.

File Decompression
-Data decompression is the reverse--the decoding of compressed data to restore the original data.
-Compression/decompression algorithms look for redundancies in data, then minimize them using predetermined algorithms (methods). There are different algorithms used to achieve different compression rates.
-Solid files are called "archives." They can hold more than one file. There is a tradeoff between higher density rates and compression/decompression time.
-Archive files can be manipulated with utilities such as WinZip or IZArc.

Internet Hard Drive
-The sole purpose of an Internet hard drive is to offer a means of accessing your computer files (pictures, documents, music, videos, etc.) from any computer, as long as that computer has access to the Internet. 
-An Internet hard drive will allow you to "deposit" your computer files into a remote hard drive, and then later access those very same files from any other computer.

Solid-State Storage
- A data storage device that uses solid-state memory to store persistent data with the intention of providing access in the same manner of a traditional block i/o hard disk drive. 
- SSDs are distinguished from traditional hard disk drives, which are electromechanical devices containing spinning disks and movable read/write heads. 
- SSDs are typically less susceptible to physical shock, are silent, and have lower access time and latency, but are more expensive per gigabyte (GB) and typically support a limited number of writes over the life of the device. 
- SSDs use the same interface as hard disk drives, thus easily replacing them in most applications.

Tuesday, May 31, 2011

System Unit


-RAM standed for Random-access memory. It refers to a storage technology that allows you to read and write data as many times as needed.

-RAM is typically erased when a computer is shut down, though some RAM chips maintain data indefinitely without electrical power.

-RAM devices are not limited to memory chips, and random-access memory as a storage format is not limited to use as working memory.

Cache Memory

-A memory cache, sometimes called a cache store or RAM cache, is a portion of memory made of high-speed static RAM (SRAM) instead of the slower and cheaper dynamic RAM (DRAM) used for main memory.

-The data that is stored within a cache might be values that have been computed earlier or duplicates of original values that are stored elsewhere.

-Some memory caches are built into the architecture of microprocessors.

-Memory caching is effective because most programs access the same data or instructions over and over.

-By keeping as much of this information as possible in SRAM, the computer avoids accessing the slower DRAM.


-Pronounced rahm, acronym for read-only memory, computer memory on which data has been prerecorded.

-Once data has been written onto a ROM chip, it cannot be removed and can only be read.

-Most personal computers contain a small amount of ROM that stores critical programs such as the program that boots the computer.

 -ROMs are used extensively in calculators and peripheral devices such as laser printers, whose fonts are often stored in ROMs.
Variation of a ROM is a PROM  (programmable read-only memory). PROMs are manufactured as blank chips on which data can be written with a special device called a PROM programmer.

Flash Memory

-Flash Memory is a non-volatile computer storagechip that can be electrically erased and reprogrammed.

-It is primarily used in memory cards, USB flash drives, MP3 players and solid-state drives for general storage and transfer of data between computers and other digital products.

 -It is a specific type of EEPROM (electrically erasable programmable read-only memory) that is erased and programmed in large blocks; in early flash the entire chip had to be erased at once.

-Flash memory costs far less than byte-programmable EEPROM and therefore has become the dominant technology wherever a significant amount of non-volatile, solid state storage is needed.

Graphic Card

-Graphics cards are PCBs (printed circuit boards) that perform the dual role of sending pixels to the display and providing a specific type of processing using a GPU (graphical processing unit).

-One of the main features of a graphics card is the ability to draw 3D graphics in realtime using a technique called rasterization.

-This involves converting 3D coordinates into areas of pixels and filling the areas with either a transformed image called a texture or a flat surface

-Most graphics cards can perform a technique called "Hardware Transform and Lighting".

-Graphics cards follow standard interfaces, such as PCI-E, PCI or AGP, meaning they are common attachments for desktop computer motherboards.

Sound Card

-Sound card is a component nside the computer that provides audio input and output capabilities.

-Most sound cards have at least one analog line input and one stereo line output connection.
Some sound cards also support digital audio input and output, either through a standard TRS (tip-ring-sleeve) connection or via an optical audio port, such as Toslink connector.

-In some computers, the sound card is part of the motherboard, while other machines may have an actual card that reside in a PCI slot.

-While professional sound cards can add more audio capabilities to your computer, another popular option for multi-channel recording is a breakout box. This is an external box that typically includes a built-in sound card and multiple audio connections.

Network Interface Card

-A network interface card (NIC) is a computer circuit board or card that is installed in a computer so that it can be connected to a network.

-Network interface cards provide a dedicated, full-time connection to a network. Most home and portable computers connect to the Internet through as-needed dial-up connection.

-The modem provides the connection interface to the Internet service provider.

Plug and Play

-Plug and Play is a term used in the computer field to describe a computer's ability to have new devices, normally peripherals, added to it without having to restart the computer.

-There are a number of terms or variations that describe similar abilities, including PnP, and hot swapping.

 -The term Plug and Play is most associated with Microsoft, who started using it in reference to their Windows 95 product.

-Plug and Play requires support both in hardware and in software.

-The hardware typically requires some sort of ID code that it can supply, in order for the computer software to correctly identify it. Apple Desktop Bus (ADB) used a simple four-bit code for this, but most systems use longer codes of several types in order to deliver more information, including names and serial numbers.

Serial Port

-The serial port is a type of connection on PCs that is used for peripherals such as mice, gaming controllers, modems, and older printers.

-It is sometimes called a COM port or an RS-232 port, which is its technical name.

 -If that's not enough to confuse you, there are two types of serial ports -- DB9 and DB25. DB9 is a 9-pin connection, and DB25 is, you guessed it, a 25-pin connection.

-A serial port can only transmit one bit of data at a time, whereas a parallel port can transmit many bits at once.

-The serial port is typically the slowest port you'll find on a PC, if you find one at all. Most newer computers have replaced serial ports with much faster and more compatible USB ports.

Parallel Port

-Parallel port is an interface from a computer system where data is transferred in or out in parallel, that is, on more than one wire.

-A parallel port carries one bit on each wire thus multiplying the transfer rate obtainable over a single cable (contrast serial port).

-There are usually several extra wires on the port that are used for control signals to indicate when data is ready to be sent or received.

-This type of port is most often used by a microprocessor to communicate with peripherals.

-The most common kind of parallel port is a printer port.

Universal serial Bus Port

-Universal serial bus, is a standardized interface that allows peripheral devices to be connected to a computer.

-Virtually all computers manufactured since early 2000 are equipped with USB ports, and the technology has cross-platform compatibility, meaning that it can be used to attach devices to Macintosh, Windows and Linux/UNIX computers.

-USB-enabled devices may be attached and disconnected from a computer while the computer is on, a process known as 'hot swapping.'
USB is an extremely versatile interface, compared to older interfaces such as serial and parallel connections.

-USB is supported by and compatible with all operating systems.

Firewire Port

-This high-speed interface has become a hot new standard for connecting peripherals.

-Created by Apple Computer in the mid-1990's, Firewire can be used to connect devices such as digital video cameras, hard drives, audio interfaces, and MP3 players, such as the Apple iPod, to your computer.

-A standard Firewire connection can transfer data at 400 Mbps, which is roughly 30 times faster than USB 1.1. This blazing speed allows for quick transfers of large video files, which is great for video-editing professionals.

-As long as your computer has PCI slots, you can purchase a PCI Firewire card to add Firewire ports to your computer.

Ethernet Port

-Ethernet is a family of frame-based computer networking technologies for local area networks (LAN).

-It defines a number of wiring and signaling standards for the Physical Layer of the standard networking model as well as a common addressing format and a variety of Medium Access Control procedures at the lower part of the Data Link Layer.

-Ethernet has been commercially available since around 1980, largely replacing competing wired LAN standards.

-Most common are Ethernet over twisted pair to connect end systems, and fiber optic versions for site backbones.

High Definition Multimedia Interface

-"High-Definition Multimedia Interface" is an industry-supported, uncompressed, all-digital audio/video interface.

-HDMI provides an interface between any compatible digital audio/video source, such as a set-top box, DVD player, and A/V receiver and a compatible digital audio and/or video monitor, such as a digital television.

-HDMI supports standard, enhanced, or high-definition video, plus multi-channel digital audio on a single cable.

-HDMI also includes support for 8-channel uncompressed digital audio.  

Sunday, May 1, 2011

Basic and Specialized Software Application

Graphical User Interface (GUI)

Graphical User Interface, and is pronounced "gooey."

It refers to the graphical interface of a computer that allows users to click and drag objects with a mouse instead of entering text at a command line.

GUIs can be used in computers, hand-held devices.

Two of the most popular operating systems, Windows and the Mac OS, are GUI-based

World Processor

A Word Processor is a computer application used for the production if any sort of printable material.

Application used for the production included composition, editing, formatting and possibly printing.

Word processor may also refer to a type of stand-alone office machine, popular in the 1970s and 1980s, combining the keyboard text-entry and printing functions of an electric typewriter with a dedicated processor (like a computer processor) for the editing of text.

 Word processors are descended from early text formatting tools. ( sometimes called text justification toolds, from their only real capability.


A Spreadsheet is a rectangular table (or grid) of information, often financial information.

A table of values arranged in rows and columns. Each value can have a predefined relationship to the other values.

Spreadsheets are largely used for accounting purposes.

Each cell contains alphanumeric text, numeric values or formulas.

A formula defines how the content of that cell is to be calculated from the contents of any other cell or combination of cells each time any cell is updated.


DBMS standed for database management system.

DBMS is a computer program designed to manage a database, a large set of structured data, and run operations on the data requested by numerous users.

Examples of DBMS use include accounting, human resources and customer support systems.

DBMS originally found only in large companies with the computer hardware needed to support large data sets.

DBMSs have more recently emerged as a fairly standard part of any company back office.

The term program is often used interchangeably with software and software application.

Utility Suites

Utility is a measure of the happiness or satisfaction gained from a good or service in economics

The concept is also used in utility functions, social welfare, Pareto maximization, Edgeworth boxes and contract curves. It is a central concept of welfare economics.

Maximisation of utility as a moral criterion for the organisation of society

Utility of individuals, aiming for 'the greatest happiness for the greatest number'.

Utility theory assumes that humankind is rational.

Web Authoring

A Website development system that allows Web pages to be visually created like a desktop publishing program.

 It generates the required HTML code for the pages and is able to switch back and forth between the page layout and the HTML.

The software is judged by its GUI tools used for designing the page at high level.

The clarity easily people can modify and maintain the site at a low level.

Audio Editing Software

Audio editing is the process of taking recorded sound and changing it directly on the recording medium. 

All programs should include play, record, cut, copy, paste and so on. This rating goes beyond the basic editing tools to include tools such as equalizers, processors, mixers, present effects, filters as well as analyzing tools like the waveform or spectrogram.

Audio editing was a new technology that developed in the middle part of the 20 century with the advent of magnetic tape recording.

Audio editors would listen to recorded tapes at low volumes, and then located specific sounds using a process called scrubbing, which is the slow rocking back and forth of the tape reels across the playback heads of the tape deck.

Bitmap Image

A bitmap is a type of graphic composed of pixels (picture element) in a grid.

Each pixel or "bit" contains color information for the image.

Bitmap graphics formats have a fixed resolution which means that resizing a bitmap graphic can result in distortion and jagged edges.

Some common bitmap formats are GIF, JPG, JPEG, TIFF, PNG, PICT, PCX, and BMP.

Photo-editors or image-editing graphocs software such as Adobe Photoshop and Corel Photo-Paint are designed for creating and editing bitmap graphics.

Desktop Publishing Program

Desktop publishing, or DTP, is the process of editing and layout of printed material for publication, such as books, magazines, brochures, and the like using a personal computer.

 Desktop publishers use programs like Adobe InDesign and QuarkXpress to create page layouts for documents they want to print.

Complete desktop publishing involves the combination of typesetting, graphic design, page layout (how it all fits on the page), and printing the document.

Publishers may also use programs like Adobe Photoshop and Illustrator to create printable images.
Word processing programs like Microsoft Word can be used for basic desktop publishing purposes.

HTML Editor

HTML editor also called an authoring tool, an HTML editor is a software program that inserts HTML code as you create a HTML file.

Some editors will provide a word processing GUI enabling users to create HTML documents without knowing any HTML code.

Image Editor

Image Editor is software that allows images to be edited and also converted to different graphic formats.

Image editors typically deal with only bitmapped images such as GIFs, JPEGs and BMPs.

However, some editors support both bitmaps and illustrations.

Common functions are manually cropping and resizing the image and using " filters" to adjust brightness, contrast and colors.

Numerous filters can be used for special effects. A myriad of filters are available for specia effects. Red eye removal is included in editors specialized for photos.


Multimedia is the integration of multiple forms of media. This includes text, graphics, audio, video.

Educational software that involves animations, sound, and text is called " multimedia software.

Multimedia is usually recorded and played, displayed or accessed by information content processing devices, such as computerized and electronic devices, but can also be part of a live performance.

Multimedia is distinguished from mixed media in fine art, by including audio.

Hypermedia can be considered one particular multimedia application.

Vector Image

Vector graphics is the use of geometrical primitives such as points, lines, curves, and shapes or polygon(s), which are all based on mathematical equations, to represent images in computer graphics.

Vector is a representation of both a quantity and a direction at the same time. In vector images, the file that results from a graphic artist's work is created and saved as a sequence of vector statements.

There are instances when working with vector tools and formats is the best practice, and instances when working with raster tools and formats is the best practice. There are times when both formats come together.

 An understanding of the advantages and limitations of each technology and the relationship between them is most likely to result in efficient and effective use of tools.

Saturday, April 23, 2011

The Internet, The Web and Electronic Commerce


URL is Uniform Resource Locater. It is address that the server connects to.
The global address of documents and other resources on the World Wide Web.
URL helps one in eraching a domain without any favoritism or bias to the various similar sounding names one uses as  a.k.a's/aliases due to the clutter existing.


HTML stands for Hyper Text Markup Language. The predominant markup language for web pages.
Originally conceived as a simple markup language to render research documents on the Web.
HTML is the basic building-blocks of web pages. 

HTML documents contain HTML tags and plain text.
Defines all the graphic elements used on the page, which are separate files on a local remote server.


Javascript is an interpreted programming or script language from Netscape.
Javascript is intamately tied to the World-Wide Web, and runs in only three environments.
That somewhat similar in capability to Microsoft's Vusual basic, Sun's Tcl, the UNIX-derived Perl,and IBM's REXX.

Ingeneral, script languages are easier and faster to code.
Javascript automatically change a formatted date on a Web page, cause a linked-to page to appear in a popup window, cause text or graphic image to change during a mouse rollover.


Applet = Apple.
An applet is any small application that performs onc specific task that runs within the scope of a larger program, often as a plug-in.
Has limited features, requires limited memory resources, and designed to be dowloaded from the Internet to run on a web page.
In some cases, an applet does not run independently.
An applet cannot read or write data on the user's machine.
The word Applet was first used in 1993 by the application AppleScript.


A blog is a mixture of what is happening in a person's life and what is happening on the Web.

It is a kind of hybrid diary or guide site, although there are many unique types of blogs and people.

The modern blog evolved from the online diary, where people would keep a running account of their lives.
Blog is a Web page that serves as a publicly accessible personal journal for an individual.

Typically updated daily, blogs often reflect the personality,comment, hyperlinks provided of the author.

A typical blog combines text, images and links to other blogs, Web pages, and other media related to its topic.


A Wiki is a Web site that allows users to add and update content on the site using their own Web browser.
Wikis end up being created mainly by a collaborative effort of the site visitors. Allows anyone visiting a website and to edit content on it.
The term "wiki" comes from the Hawaiian phrase, "wiki wiki", which means " super fast".
Wiki supports hyperlinks and has a simple text syntax for creating new pages and crosslinks between internal pages on the fly.
A great example of a larger wiki is the Wikipedia.

Short stand for File Transfer Protocol, the protocol for exchanging files over the Internet.
 A communications protocol govering the transfer of files from one computer to another over a network.
FTP works in the same way as HTTP for transfering Web pages from a server to a user's browser and SMTP for transferring electronic mail across the Internet in that.
FTP uses the Internet's TCP/IP protocols to ebavle data transfer.
FTP servers can be configured to allow anonymous access.


A hardware or software module that adds a specific feature or service to a larger system.

A software plug-in is an add-on for a program that adds functionality to it.

Plug-in applications are programs that can easily be installed and used as part of your Web browser.

A plug-in application is recognized automatically by the browser and its function is integrated into the main HTML file that is being presented.

Most graphics and audio programs today support plug-ins since they are a convenient way to expand the capabilities of the program.

A filter is a program or section of code that is designed to examine each input or output request for certain qualifying and then process it accordingly.
A filter is " pass-through" code that takes input data.
Usually, a filter does no input or output operation on its own.
Filters are sometimes used to remove or insert headers or control characters in data.

-Internet Security Suite
A suite of utilities for maintaining the security of a Windows PC from McAfee.
Formerly called McAfee Office, it includes more than a dozen utilities such as anti virus, personal firewall, spam blocker and pop up blocker.