1. A+ Certification A certification program from the CompTIA (Computer Technology Industry Association) designed to measure competence in basic computer repair and aimed at the computer technician. Certification requires passing two tests: a core exam to test general knowledge of PCs, including configuration, installation and upgrading, diagnosis, repair, maintenance, customer interaction, and safety, and at least one specialty exam that tests operating system knowledge.
2. A+B signaling A type of in-band signaling used in T1 transmission; 1 bit from each of the 24 subchannels in every sixth frame is used to carry dialing and other control information. A+B signaling reduces the T1 bandwidth from 1.544Mbps to 1.536 Mbps.
3. a-b box A switching box that allows two or more computers to share a peripheral device such as a printer. It can be switched manually or through software.
4. A/UX A version of the Unix operating system that runs on the Macintosh. A/UX is based on the System V release 2 of Unix and includes a number of Apple features, such as support for the Macintosh Toolbox. This support allows applications running under A/UX to use the familiar Macintosh user interface. You need a Macintosh II with a Motorola 68020 or higher microprocessor and at least 4MB of memory to use A/UX. See also Unix.
5. AAL See ATM Adaptation Layer.
6. AASE See Associate Accredited Systems Engineer.
7. ABCP See Associate Business Continuity Professional.
8. abend Contraction of abnormal end. A message issued by an operating system when it detects a serious problem, such as a hardware failure or major software damage.
9. ABI See Application Binary Interface.
10. ABR See Available Bit Rate.
11. ABUI See Association of Banyan Users International.
12. accelerator board An add-in, printed circuit board that replaces the main processor with a higher-performance processor. Using an accelerator board can reduce upgrading costs substantially, because you don’t need to replace the monitor, case, keyboard, and so on. However, the main processor is not the only component that affects the overall performance of your system. Other factors, such as disk-access time and video speed, contribute to a system’s performance. See also graphics accelerator board.
13. access To use, write to, or read from a file, or to log in to a computer system or network.
14. AccessBuilder Remote access software from 3Com Corporation that lets you access network resources over a dial-up connection from a remote location.
15. access control entry Abbreviated ACE. The basic unit of security in Microsoft Windows 2000 that controls access to the file system, to Active Directory objects, to printers and other network resources, and to the Registry. An ACE consists of a security identifier (SID) and an access mask that defines the access rights of that SID. A collection of ACEs that control access to an object is known as an access control list. See also access control list; security identifier.
16. access control list Abbreviated ACL. A list or table containing information about the users, processes, and objects that can access a specific file or object. ACLs are usually attached to file-system directories, and they specify access permissions such as read, write, execute, delete, and so on. ACLs are implemented in Novell NetWare, Microsoft Windows 2000, and Unix: In Novell Directory Services, ACLs are associated with every object in the NDS tree, storing the list of rights for each trustee that can access the object. _ In the Unix Network File System, ACLs include the name of the user or group, along with the rights granted to that user or group. _ In Windows 2000, everything is an object, and every object has an associated ACL.See also Active Directory; authentication; NDS tree; Novell Directory Services; rights; security.
17. access method The set of rules that determines which node in a network has access to the transmission media at any moment. Attempts at simultaneous access are either managed by a collision detection mechanism such as CSMA/CD or prevented by use of a token-passing method.
18. access protocol The set of rules that workstations use to avoid collisions when sending information over shared network media. Also known as the media access control protocol.
19. access rights See rights.
20. access server A computer that provides access for remote users who dial in to the system and access network resources as though their computers were directly attached to the network. See also communications/modem server; mobile computing.
21. access time The period of time that elapses between a request for information from disk or memory and the arrival of that information at the requesting device. Memory-access time refers to the time it takes to transfer a character between memory and the processor. Disk-access time refers to the time it takes to place the read/ write heads over the requested data. RAM may have an access time of 80 nanoseconds or less, while hard-disk access time could be 10 milliseconds or less.
22. access token In Microsoft Windows 2000, an object that contains the security identifier (SID) of a running process. When a process is started by another process, the second process inherits the starting process’s access token. This access token is then checked against each object’s access control list to confirm that the appropriate permissions are in place to permit any services requested by the process. See also access control list; permissions; process; rights.
23. account On LANs or multiuser operating systems, an account is set up for each user. Accounts are usually kept for administrative or security reasons. For communications
and online services, accounts identify a subscriber for billing purposes. See also user account.
24. accounting The process of tracking the resources on a network. The network administrator can charge for files accessed, connect time, disk space used for file storage, and service requests by assigning account balances to users. The users can then draw from their account balances as they use network services.
25. account lockout In Microsoft Windows 2000 and other operating systems, a count of the number of invalid logon attempts allowed before a user is locked out. See also authentication; user account.
26. account policy On networks and multiuser operating systems, the set of rules that defines whether a new user is permitted access to the system and whether an existing user is granted additional rights or expanded access to other system resources. Account policy also specifies the minimum length of passwords, the frequency with which passwords must be changed, and whether users can recycle old passwords and use them again.
27. Accredited Systems Engineer Abbreviated ASE. A certification from Compaq designed to evaluate and recognize expertise in installing and administering Compaq workstations and servers running both Microsoft Windows 2000 and Novell Net- Ware network operating systems. See also Associate Accredited Systems Engineer.
28. ACE See access control entry.
29. Acer Group One of the top five PC makers in the world, with factories in Malaysia, the Netherlands, the Philippines, Taiwan, and the United States. The Acer Group bought Texas Instrument’s notebook computer business in 1997 and has formed business alliances with companies, including 3Com and Hitachi, for the development of advanced digital consumer products such as PC-ready televisions and DVD systems. For more information on the Acer Group, see www.acer.com.tw.
30. ACF See Advanced Communications Function.
31. ACK See acknowledgment.
32. acknowledgment Abbreviated ACK. In communications, ACK is a control code, ASCII 06, sent by the receiving computer to indicate that the data has been received without error and that the next part of the transmission may be sent. See also NAK.
33. ACL See access control list.
34. ACONSOLE A Novell NetWare 3.x workstation utility that controls a modem attached to the workstation. ACONSOLE is used to establish an asynchronous remote console connection to a server. The RS232 NetWare Loadable Module (NLM) must be loaded on the server to which you want to connect. In NetWare 4.x, use RCONSOLE to perform this function.
35. acoustic coupler A modem that includes a pair of rubber cups that fit over the mouthpiece and earpiece of a standard telephone handset (to prevent external noise from being picked up). An acoustic coupler allows you to connect your computer to a telephone system that does not have the standard RJ-11 connections used with conventional modems.
36. ACPI See Advanced Configuration and Power Interface.
37. ACR See Available Cell Rate.
38. across-the-wire migration A method of migrating file-server data, trustee rights, and other information to a Novell Net-Ware server using the NetWare Migration utility. You can also use across-the-wire migration to upgrade from LAN Manager, LAN Server, and earlier versions of Net-Ware; a similar process known as BMIGRATE allows users to migrate from Banyan VINES.
39. ACS See Advanced Communications Service.
40. ACTE See Ascend Certified Technical Expert.
41. Active Desktop In Microsoft Windows, a user interface feature that makes the Desktop look and behave just like a Web page, with underlined icons and a hand mouse pointer. Active Desktop is offered as an alternative to the classic Windows user interface; you can use Active Desktop, you can use the classic Windows interface, or you can swap back and forth between the two.
42. Active Directory In Microsoft Windows 2000, a system for large-scale network management that views the network as a hierarchy of objects. Active Directory does the following: _ Provides a hierarchy for the management of all network objects, including users, servers, services, file shares, Web pages, printers, and so on. _ Divides administration and security into sub domains, domains, and trees of domains. _ Scales to 10 million users per domain. _ Implements MIT’s Kerberos authentication system based on private key encryption and also supports public key encryption for authentication of clients and business partners.