glossary-from-whatiscom137.doc 2015/1/30
glossary-from-whatiscom137.doc 2015/1/30
The name of the domain is like the name of a person, and the IP address is like h...
glossary-from-whatiscom137.doc 2015/1/30
glossary-from-whatiscom137.doc 2015/1/30
Computer instructions or data. Anything that can be stored electronicall...
glossary-from-whatiscom137.doc 2015/1/30
being widely used. CRT (Cathode Ray Tube) monitors are the traditional monitors t...
glossary-from-whatiscom137.doc 2015/1/30
monitors produce less heat. They consume less energy than CRT monitors. Besides,
glossary-from-whatiscom137.doc 2015/1/30
Bluetooth was invented by L.M. Ericsson of Sweden in 1994, it is a cable-replacem...
glossary-from-whatiscom137.doc 2015/1/30
8 beeps Video memory error. The BIOS cannot write to the frame buffer memory on t...
glossary-from-whatiscom137.doc 2015/1/30
can run a different program or display a different file. You can move windows
glossary-from-whatiscom137.doc 2015/1/30
Electronic junk mail or junk newsgroup postings. Some people define spam even mor...
glossary-from-whatiscom137.doc 2015/1/30
(2) To copy commercial software illegally by breaking (cracking) the various copy...
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  1. 1. glossary-from-whatiscom137.doc 2015/1/30 Internet Phone (Soft Phone) A popular VoIP application. There are actually two different products called Internet Phone, one produced by Intel and the other developed by VocalTec Ltd. VoIP Short for Voice over Internet Protocol, a category of hardware (mic & speaker) and software (e.g. CoolTalk, NetMeeting + msn messenger, Skype, NetTalk, ICQ phone, Yahoo messenger voice chat, QQ) that enables people to use the Internet as the transmission medium for telephone calls by sending voice data in packets using IP rather than by traditional circuit transmissions of the PSTN (Public Switched Telephone Network). Advantage: no surcharge (except for Internet access) like sending e-mails over the Internet, data compression, higher bandwidth VoIP also is referred to as Internet telephony, IP telephony, or Voice over the Internet (VOI) DNS (Domain Name System) The Domain Name System is a distributed database. This allows local control of the segments of the overall database, yet data in each segment are available across the entire network through a client-server scheme. Robustness and adequate performance are achieved through replication and caching. Programs called Name Server comprise the server half of DNS's client server mechanism. Name servers contain information about some segment of the database and make it available to clients, called Resolvers. Resolvers are often just library routines that create queries and send them across a network to a name server. The whole database is like an inverted tree, with the root at the top. The first row of the name is the last part (TLD) of the domain name, which is either "com", "net", "edu", "gov", "mil", ... Or a two letter country code, like "tw" for Taiwan, "uk" for United Kingdom, "th" for Thailand, ... followed by the next row with, "com", "net", "edu", "gov", "mil", ... In the next row we find the name of the domain, and in below rows we find the sub domains and hosts. p.1
  2. 2. glossary-from-whatiscom137.doc 2015/1/30 The name of the domain is like the name of a person, and the IP address is like his phone number. We call a person with the phone by dialing the phone number. On the Internet we have IP numbers for each host (computer, server, router, ...), and we give these IP numbers an easy to remember name, which are organized into the domain name. If you are connected to the Internet, DNS is therefore a must. Top Level Domain (TLD) TLD identifies the most general part of the domain name in an Internet address. A TLD is either a generic top-level domain (gTLD), such as "com" for "commercial," "edu" for "educational," and so forth, or a country code top-level domain (ccTLD), such as "fr" for France, "cn" for China, "hk" for Hong Kong or "is" for Iceland. Static IP If the host is permanent connected to the Internet, than the computer will have got a permanent IP address, which is under IPv4 something like, a group of 4 numbers which can have the values up to 255 each. A static IP address will be provided to the computer from the ISP where the computer is connected. The ISP has got a range of IP addresses, which it distributes to their customers. All hosts are in a (static) database of a DNS. All names are resolved to their IP address. Dynamic IP If the host is not permanent connected to the Internet, than the computer will get a temporary IP address assigned from the ISP. These dynamic IP addresses are random assigned out of a pool of the ISP. Usually all dialup accounts will get a dynamic IP address. That means, as soon the user does not need to be connected to the Internet anymore, this IP address falls back into the pool for re-use by another dialup user. Usually a dialup user do not run a server, therefore he does not need static IP address. Dynamic DNS (Domain Name System) a method of keeping a domain name linked to a changing IP address as not all computers use static IP addresses. Typically, when a user connects to the Internet, the user's ISP assigns an unused IP address from a pool of IP addresses, and this address is used only for the duration of that specific connection. This method of dynamically assigning addresses extends the usable pool of available IP addresses. A dynamic DNS service provider uses a special program that runs on the user's computer, contacting the DNS service each time the IP address provided by the ISP changes and subsequently updating the DNS database to reflect the change in IP address. In this way, even though a domain name's IP address will change often, other users do not have to know the changed IP address in order to connect with the other computer (Dynamic DNS Providers List) p.2
  3. 3. glossary-from-whatiscom137.doc 2015/1/30 Every time your computer (as a server, with domain name is new connected to the Internet, it first checks its own (new) IP address and requests an update of the dynamic DNS automatically. The update is done within a second. Users who are accessing your server will be guided to the new IP address automatically. UPS (uninterruptible power supply) a power supply that includes a battery to maintain power in the event of a power outage. Typically, a UPS keeps a computer running for several minutes after a power outage, enabling you to save data that is in RAM and shut down the computer gracefully. Many UPSs now offer a software component that enables you to automate backup and shut down procedures in case there's a power failure while you're away from the computer. Firewall a protection scheme based on ASA (ASA tracks the source and destination address, TCP sequence numbers, port numbers, and additional TCP flags of each packet), which offers stateful connection-oriented security. This information is stored in a table, and all inbound and outbound packets are compared against entries in the table Adaptive Security Algorithm  The ASA (Adaptive Security Algorithm) is the heart of the PIX Firewall  ASA is stateful and connection oriented  The ASA design creates session flows based on:  Source and destination addresses  TCP sequence numbers  Port numbers  TCP flags By applying the security policy to the connection table entries, inbound and outbound traffic can be controlled Hardware Refers to objects that you can actually touch, like disks, disk drives, display screens, keyboards, printers, boards, and chips. In contrast, software is untouchable. Software exists as ideas, concepts, and symbols, but it has no substance. Books provide a useful analogy. The pages and the ink are the hardware, while the words, sentences, paragraphs, and the overall meaning are the software. A computer without software is like a book full of blank pages -- you need software to make the computer useful just as you need words to make a book meaningful. p.3
  4. 4. glossary-from-whatiscom137.doc 2015/1/30 Software Computer instructions or data. Anything that can be stored electronically is software. The storage devices and display devices are hardware. Software is often divided into two categories:  systems software : Includes the operating system and all the utilities that enable the computer to function.  applications software : Includes programs that do real work for users. For example, word processors, spreadsheets, and database management systems fall under the category of applications software. Firmware Firmware is programming that is inserted into programmable read-only memory (programmable ROM), thus becoming a permanent part of a computing device. Firmware is created and tested like software (using microcode simulation). When ready, it can be distributed like other software and, using a special user interface, installed in the programmable read-only memory by the user. Firmware is sometimes distributed for printers, modems, and other computer devices. Software (programs or data) that has been written onto read-only memory (ROM). Firmware is a combination of software and hardware. ROMs, PROMs and EPROMs that have data or programs recorded on them are firmware. System software Refers to the operating system and all utility programs that manage computer resources at a low level. Software is generally divided into systems software and applications software. Applications software comprises programs designed for an end user, such as word processors, database systems, and spreadsheet programs. Systems software includes compilers, loaders, linkers, and debuggers. Applications Software Word Processing Graphics Spreadsheets Communications Database Games System Software Assembler Debugger Compilers File Management Tools Operating System Utilities Computer Hardware Comparison between LCD monitors and CRT monitors PC monitors are not all the same any more. There are two types of monitors that are p.4
  5. 5. glossary-from-whatiscom137.doc 2015/1/30 being widely used. CRT (Cathode Ray Tube) monitors are the traditional monitors that we have been using for years. LCD (Liquid Crystal Display) monitors are now becoming popular, because of their great space saving advantage. Now, let's take a look at some of the differences between the LCD monitors and CRT monitors. Physical Size One of the greatest advantages of LCD monitors is that they are more compact and lightweight compared with CRT monitors. LCD monitors take up less room, so they can be used in many places where a larger CRT monitor cannot fit. Side view of an LCD monitor & CRT monitor Display Characteristics  Brightness and Colours LCD screens are generally not as bright as CRT screens. Many LCD monitors are only capable of displaying thousands of colours, while CRT monitors are capable of displaying unlimited colours.  Resolution Most LCD monitors (15”) available on the market have maximum resolutions of 1024 5 768. A 15” CRT monitor, although has a slightly smaller viewing area than a typical 15” LCD monitor, is capable of displaying a maximum resolution of 1280 5 1024.  Viewing Angle LCD monitors have a much smaller viewing angle than that of CRT monitors. A CRT screen can be viewed from its side, whereas an LCD screen can only be viewed directly from its front. If a person looks at an LCD screen from the side, the image on the screen may seem to disappear or the colour of the image may not be so clear. Viewing angle of an LCD monitor and a CRT monitor  Power Consumption and Radiation Emission LCD monitors are generally more environmental friendly than CRT monitors. LCD p.5
  6. 6. glossary-from-whatiscom137.doc 2015/1/30 monitors produce less heat. They consume less energy than CRT monitors. Besides, LCD monitors do not emit harmful radiation as CRT monitors do. By better technology and higher volume of production, LCD monitors not only become less and less expensive, but also provide better quality in display characteristics (brightness, clearness and sharpness). It is believed that more consumers will switch from the conventional CRT monitors to LCD monitors in the near future. PDA PDA stands for Personal Digital Assistant, which is a hand-held computer that allows users to store, access, and organize information. A variety of PDAs such as Pocket PC, Handheld Organizer, or Palms are available on markets. The prices of most PDAs range from $100 to $600. PDAs have built-in memory range from 2MB to 64 MB. Memory of some PDAs can be expanded by inserting small storage cards. PDAs range from the size and thickness of 10 business cards, weighing 40 grams, to the size of a pocket- sized book weighing significantly more. Users have to use a pen-like stylus to input data into most of the PDAs. Users can either enter data by tapping on an on- screen keyboard or enter data by writing on the screen. PDAs are equipped with almost everything one might need from a computer when on the move. Basic PDAs allows users to store and retrieve addresses, phone numbers, maintain a calendar, and creating to-do lists and notes. More sophisticated PDAs can run word processing, spreadsheet, money manager, games and electronic book reading programs, they contain fax functionality and also provide wireless access to e-mail and the Internet. Moreover, PDA can also easily share information with Windows-based or Macintosh computers easily, that allow users to transfer files and synchronize the data on both the PDA and the laptop computer. PDA can transfer the information to other PDAs with infrared technology. In fact, there are thousands of programs that can increase the efficiency and power of the PDAs. The users can simply upgrade the programs by downloading the software from the Internet. Bluetooth What is Bluetooth? Bluetooth is the name of a new technology standard for a small, cheap radio chip to be plugged into portable and/or fixed electronic devices. It allows a wide range of devices to communicate with each other wirelessly. How Bluetooth works? p.6
  7. 7. glossary-from-whatiscom137.doc 2015/1/30 Bluetooth was invented by L.M. Ericsson of Sweden in 1994, it is a cable-replacement technology. A Bluetooth chip is a microcomputer chip, which is able to transmit or receive a special radio frequency. For example, a mobile phone which contains a Bluetooth chip can transmit an information to the electronic system in an automobile, which has a built-in Bluetooth chip, in order to demand the automobile to lock up the doors. General applications of Bluetooth Bluetooth offers wireless access to local area network (LAN), public switched telephone network (PSTN), the mobile phone network and the Internet for a host of home appliances and portable handheld interfaces. With Bluetooth, devices such as laptop computers, handheld computers, cellular telephones, pagers, fax machines, and printers can wirelessly communicate with each other. Although the Bluetooth technology can overcome the limitations of the wired networks, there is still room for further development before it is widely adopted. BIOS Beep Codes When a computer is first turned on, or rebooted, its BIOS performs a power-on self test (POST) to test the system's hardware, checking to make sure that all of the system's hardware components are working properly. Under normal circumstances, the POST will display an error message; however, if the BIOS detects an error before it can access the video card, or if there is a problem with the video card, it will produce a series of beeps, and the pattern of the beeps indicates what kind of problem the BIOS has detected. Because there are many brands of BIOS, there are no standard beep codes for every BIOS. The two most-used brands are AMI (American Megatrends International) and Phoenix. Below are listed the beep codes for AMI systems, and here are the beep codes for Phoenix systems. AMI Beep Codes Beep Code Meaning 1 beep DRAM refresh failure. There is a problem in the system memory or the motherboard. 2 beeps Memory parity error. The parity circuit is not working properly. 3 beeps Base 64K RAM failure. There is a problem with the first 64K of system memory. 4 beeps System timer not operational. There is problem with the timer(s) that control functions on the motherboard. 5 beeps Processor failure. The system CPU has failed. 6 beeps Gate A20/keyboard controller failure. The keyboard IC controller has failed, preventing gate A20 from switching the processor to protect mode. 7 beeps Virtual mode exception error. p.7
  8. 8. glossary-from-whatiscom137.doc 2015/1/30 8 beeps Video memory error. The BIOS cannot write to the frame buffer memory on the video card. 9 beeps ROM checksum error. The BIOS ROM chip on the motherboard is likely faulty. 10 beeps CMOS checksum error. Something on the motherboard is causing an error when trying to interact with the CMOS. 11 beeps Bad cache memory. An error in the level 2 cache memory. 1 long beep, 2 short Failure in the video system. 1 long beep, 3 short A failure has been detected in memory above 64K. 1 long beep, 8 short Display test failure. Continuous beeping A problem with the memory or video. Graphical User Interface (GUI) a method of interacting with a computer through direct manipulation of graphical images and widgets (graphical components or controls) in addition to text (using mouse and keyboard). Examples of widgets: • button • check box • radio button • combo box • icon • text box (edit field) • tooltip • scrollbar • status bar • toolbar • menu • window A program interface that takes advantage of the computer's graphics capabilities to make the program easier to use. Well-designed graphical user interfaces can free the user from learning complex command languages. On the other hand, many users find that they work more effectively with a command-driven interface, especially if they already know the command language. Graphical user interfaces, such as Microsoft Windows and the one used by the Apple Macintosh, feature the following basic components:  pointer : A symbol that appears on the display screen and that you move to select objects and commands. Usually, the pointer appears as a small angled arrow. Text -processing applications, however, use an I-beam pointer that is shaped like a capital I.  pointing device : A device, such as a mouse or trackball, that enables you to select objects on the display screen.  icons : Small pictures that represent commands, files, or windows. By moving the pointer to the icon and pressing a mouse button, you can execute a command or convert the icon into a window. You can also move the icons around the display screen as if they were real objects on your desk.  desktop : The area on the display screen where icons are grouped is often referred to as the desktop because the icons are intended to represent real objects on a real desktop.  windows: You can divide the screen into different areas. In each window, you p.8
  9. 9. glossary-from-whatiscom137.doc 2015/1/30 can run a different program or display a different file. You can move windows around the display screen, and change their shape and size at will.  menus : Most graphical user interfaces let you execute commands by selecting a choice from a menu. The first graphical user interface was designed by Xerox Corporation's Palo Alto Research Center in the 1970s, but it was not until the 1980s and the emergence of the Apple Macintosh that graphical user interfaces became popular. One reason for their slow acceptance was the fact that they require considerable CPU power and a high- quality monitor, which until recently were prohibitively expensive. In addition to their visual components, graphical user interfaces also make it easier to move data from one application to another. A true GUI includes standard formats for representing text and graphics. Because the formats are well-defined, different programs that run under a common GUI can share data. This makes it possible, for example, to copy a graph created by a spreadsheet program into a document created by a word processor. Many DOS programs include some features of GUIs, such as menus, but are not graphics based. Such interfaces are sometimes called graphical character-based user interfaces to distinguish them from true GUIs. DOS (disk operating system) most often refer to MS-DOS (Microsoft disk operating system). Originally developed by Microsoft for IBM-compatible personal computers (PC). DOS is a 16-bit operating system and does not support multiple users or multitasking. CLI versus GUI Command Line Interface (CLI) Graphical User Interface (GUI) command line system with keyboard menu-driven system with icons run in a character-cell text mode run in a pixel-based graphics mode difficult to learn, not user friendly easy to learn, shorter learning path users have to remember DOS commands no need to remember commands user must have good knowledge of the computer not necessary requires training and special skills requires less skills and training suitable for experienced user suitable for inexperienced user system requirement: simple computer system with very little resources (CPU speed, RAM, disk space, display resolution) system requirement: require more computer power (CPU speed, RAM, disk space, display resolution and response, etc.) Spam p.9
  10. 10. glossary-from-whatiscom137.doc 2015/1/30 Electronic junk mail or junk newsgroup postings. Some people define spam even more generally as any unsolicited e-mail. However, if a long-lost brother finds your e-mail address and sends you a message, this could hardly be called spam, even though it's unsolicited. Real spam is generally e-mail advertising for some product sent to a mailing list or newsgroup. In addition to wasting people's time with unwanted e-mail, spam also eats up a lot of network bandwidth. Consequently, there are many organizations, as well as individuals, who have taken it upon themselves to fight spam with a variety of techniques. But because the Internet is public, there is really little that can be done to prevent spam, just as it is impossible to prevent junk mail. However, some online services have instituted policies to prevent spammers from spamming their subscribers. There is some debate about the source of the term, but the generally accepted version is that it comes from the Monty Python song, "Spam spam spam spam, spam spam spam spam, lovely spam, wonderful spam…" Like the song, spam is an endless repetition of worthless text. Another school of thought maintains that it comes from the computer group lab at the University of Southern California who gave it the name because it has many of the same characteristics as the lunchmeat Spam: Nobody wants it or ever asks for it. No one ever eats it; it is the first item to be pushed to the side when eating the entree. Sometimes it is actually tasty, like 1% of junk mail that is really useful to some people. Hacker A slang term for a computer enthusiast, i.e., a person who enjoys learning programming languages and computer systems and can often be considered an expert on the subject(s). Among professional programmers, depending on how it used, the term can be either complimentary or derogatory, although it is developing an increasingly derogatory connotation. The pejorative sense of hacker is becoming more prominent largely because the popular press has co-opted the term to refer to individuals who gain unauthorized access to computer systems for the purpose of stealing and corrupting data. Hackers, themselves, maintain that the proper term for such individuals is cracker. Cracker (1) To break into a computer system. The term was coined in the mid-80s by hackers who wanted to differentiate themselves from individuals whose sole purpose is to sneak through security systems. Whereas crackers sole aim is to break into secure systems, hackers are more interested in gaining knowledge about computer systems and possibly using this knowledge for playful pranks. Although hackers still argue that there's a big difference between what they do and what crackers do, the mass media has failed to understand the distinction, so the two terms -- hack and crack -- are often used interchangeably. p.10
  11. 11. glossary-from-whatiscom137.doc 2015/1/30 (2) To copy commercial software illegally by breaking (cracking) the various copy- protection and registration techniques being used. Operating System • Processor management • Memory management • Device management • Storage management • Application interface • User interface p.11