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| MCSE on Windows Server 2003 Certification Requirements |
| 2008-03-10 05:59:39 |
| The strength of Windows Server 2003 in the market today indicates that demand for related IT expertise will continue for years to come. The best way to demonstrate your expert skills on Windows Server 2003—and to inspire confidence in a hiring manager, your team, and yourself—is by earning the Microsoft Certified Systems Administrator (MCSA) and Microsoft Certified Systems Engineer (MCSE) credentials.In addition, if you are certified on Windows Server 2003, you have an efficient path to the Windows Server 2008 certifications.The MCSE credential verifies your ability to analyze the business requirements
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| MCSA/MCSE 70-291 Exam Cram |
| 2008-03-10 05:57:43 |
MCSA/MCSE 70-291 Exam Cram, Second Edition "is the #1 quick-study guide to passing the MCSA/MCSE 70-291 exam. This book covers all exam objectives, including how to maintain a DHCP server, manage name resolution with DNS, secure networks using IPSec, troubleshoot network and Internet connectivity, and monitor network traffic. This new edition also includes two full practice exams and has been updated against Microsoft' s official courseware (MOC) that corresponds to this exam. This book will provide a refresher on important concepts and help you build on a solid foundation of knowledge on exam topics and objectives. The book also features test-taking strategies, time-saving study tips, and a special Cram Sheet that includes tips, acronyms, and memory...
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| iSCSI |
| 2008-03-10 01:31:11 |
FunctionalityiSCSI (pronounced /ajskʌzi/) uses TCP/IP (typically TCP port 3260). In essence, iSCSI simply allows two hosts to negotiate and then exchange SCSI commands using IP networks. By doing this, iSCSI takes a popular high-performance local storage bus and allows it to be run over wide-area networks, creating a storage area network (SAN). Unlike some SAN protocols, iSCSI requires no dedicated cabling; it can be run over existing switching and IP infrastructure. As a result, iSCSI is often seen as a low-cost alternative to Fibre Channel, which requires dedicated infrastructure.Although iSCSI can be used to communicate with arbitrary types of SCSI devices, it is almost always used to allow server computers (such as database servers) to access disk volumes on storage arrays. iSCSI SANs...
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| Disk enclosure |
| 2008-03-10 01:29:52 |
BenefitsFactory-assembled Buffalo external hard drive in a disk enclosureFactory-assembled Buffalo external hard drive in a disk enclosureKey benefits to using external disk enclosures include: * Adding additional storage space and media types to small form factor and laptop computers, as well as sealed embedded systems, such as digital video recorders. * Adding more drives to any given server or workstation than their chassis can hold. * Transferring data between non-networked computers, jokingly known as sneakernet. * Adding a backup source with a separate power supply from the connected computer. * Sharing the data on a drive in a network-aware enclosure. * Preventing the heat from a disk drive from increasing the heat inside an operatin...
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| Storage area network |
| 2008-03-10 01:29:10 |
Network typesMost storage networks use the SCSI protocol for communication between servers and disk drive devices. However, they do not use SCSI low-level physical interface (e.g. cables), as its bus topology is unsuitable for networking. To form a network, a mapping layer is used to other low-level protocols: * "iFCP"[1] or "SANoIP"[2] mapping SCSI over Fibre Channel Protocol (FCP) over IP. * iSCSI, mapping SCSI over TCP/IP. * iSER, mapping iSCSI over InfiniBand (IB). * HyperSCSI, mapping SCSI over Ethernet. * FICON mapping over Fibre Channel (used by mainframe computers). * ATA over Ethernet, mapping ATA over Ethernet. * Fibre Channel over Ethernet (http://open-fcoe.org/)[edit] Storage sharingHisto...
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| File Area Networking |
| 2008-03-10 01:28:09 |
BackgroundData storage technology over the years has evolved from a direct attached storage model (DAS) to two other means of connecting applications to their storage – namely Network Attached Storage (NAS) and a Storage Area Network (SAN). Since all three techniques generally differ after the file system API level, it is possible to move between these different storage models with minimal or no impact to the applications themselves and without requiring a re-write of the application unless an application has been communicating directly with the storage hardware and not going through a standard operating system supported interface.[edit] DAS Main article: Direct-attached storageHaving storage directly attached to the workstations and application servers...
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| Clustered NAS |
| 2008-03-10 01:27:17 |
A clustered NAS is a Network-attached storage solution which is using a distributed file system running simultaneously on multiple servers. The key differentiating factor of clustered NAS from traditional NAS is its ability to stripe data and metadata across the cluster nodes and storage subsystems, and provide access to the networked file system from any of the cluster nodes, unrelated to the actual location of the data. For this reason clustered NAS solutions are typically associated with virtualization....
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| List of NAS manufacturers |
| 2008-03-10 01:26:20 |
* Aberdeen LLC * ACMA Computers Inc * Adaptec - Snap Servers * Agami Systems * Allnet * AMAX Engineering Inc * Apple Inc * AV-NAS (Avante Digital) * Asus * Attune Systems * BlueArc * Buffalo * Broadberry Data Systems * CLAXAN * Comgears Technology www.comgears.com * Conceptronic [1] This page links here and is a redirect with possibilities. You can help by eliminating the redirect command in the redirecting page and expanding it. * D-Link * Dell * EMC * Exanet * Fantom Drives * Flepo * FortuNAS * Freecom * Galaxy Metal Gear * HP * Hitachi * IBM * IOGEAR * Infrant * Intellinet * Intel * Intradisk * Iomega * Isilon * ixsystems * LaCie * Level 1 * Linksys * Longshine * Media...
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| Network-attached storage |
| 2008-03-10 01:25:22 |
DescriptionNAS hardware is similar to the traditional file server equipped with direct attached storage. However it differs considerably on the software side. The operating system and other software on the NAS unit provides only the functionality of data storage, data access and the management of these functionalities. Use of NAS devices for other purposes (like scientific computations or running database engine) is strongly discouraged[citation needed]. Many vendors also purposely make it hard to develop or install any third-party software on their NAS device by using closed source operating systems and protocol implementations[citation needed]. In other words, NAS devices are server appliances.NAS units also usually h...
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| Duplex mismatch |
| 2008-03-10 00:43:23 |
Duplex mismatch due to autonegotiationOn some Ethernet networks, autonegotiation is disabled on all ports that are capable of it, and a fixed modality of 100 Mbit/s and full duplex is used to ensure maximum performance. This was especially done by network administrators upon the introduction of autonegotiation, because of interoperability issues with the initial autonegotiation specification. A fixed mode of operation works if both ends of a connection are locked to the same settings. However, maintaining such a network and guaranteeing consistency is difficult. Since autonegotiation is generally the manufacturers default setting it is almost certain that, in an environment where the policy is to fix port settings, sooner or later someone will leave a port...
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| Carrier sense multiple access with collision detection |
| 2008-03-10 00:42:37 |
Carrier Sense Multiple Access With Collision Detection (CSMA/CD), in computer networking, is a network control protocol in which * a carrier sensing scheme is used. * a transmitting data station that detects another signal while transmitting a frame, stops transmitting that frame, transmits a jam signal, and then waits for a random time interval (known as "backoff delay" and determined using the truncated binary exponential backoff algorithm) before trying to send that frame again.CSMA/CD is a modification of pure Carrier Sense Multiple Access (CSMA).Collision detection is used to improve CSMA performance by terminating transmission as soon as a collision is detected, and reducing the probability of a second collision on retry.Methods for collision de...
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| Ethernet crossover cable |
| 2008-03-10 00:42:13 |
OverviewThe 10BASE-T and 100BASE-TX Ethernet standards use one wire pair for transmission in each direction. The Tx+ line from each device connects to the tip conductor and the Tx- line is connected to the ring. This requires that the transmit pair of each device be connected to the receive pair of the device on the other end. When a terminal device is connected to a switch or hub, this crossover is done internally in the switch or hub. A standard straight through cable is used for this purpose where each pin of the connector on one end is connected to the corresponding pin on the other connector.One terminal device may be connected directly to another without the use of a switch or hub, but in that case the crossover must be done externally in the cable. S...
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| Coaxial cable |
| 2008-03-10 00:40:23 |
Coaxial cable is an electrical cable consisting of an inner conductor or several uninsulated conductors tightly twisted together, often surrounded by an insulating spacer, surrounded by an outer cylindrical conducting shield (sheath), and usually surrounded by a final insulating layer (jacket). The term coaxial comes from the inner conductor and the outer shield sharing ("co-") the same axis. It is often used as a high-frequency transmission line to carry a high-frequency or broadband signal but may also be used for frequencies as low as audio frequency. The electromagnetic field carrying the signal exists (ideally) only in the space between the inner and outer conductors. The shielding reduces interference from external electromagnetic fields, although coa...
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| Voltage regulator |
| 2008-03-10 00:39:13 |
is an electrical regulator designed to automatically maintain a constant voltage level.It may use an electromechanical mechanism, or passive or active electronic components. Depending on the design, it may be used to regulate one or more AC or DC voltages.With the exception of shunt regulators, all modern electronic voltage regulators operate by comparing the actual output voltage to some internal fixed reference voltage. Any difference is amplified and used to control the regulation element. This forms a negative feedback servo control loop. If the output voltage is too low, the regulation element is commanded to produce a higher voltage. For some regulators if the output voltage is too high, the regulation element is commanded to produce a lower voltage...
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| DC to DC converter |
| 2008-03-10 00:38:03 |
UsageDC to DC converters are important in portable electronic devices such as cellular phones and laptop computers, which are supplied with power from batteries primarily. Such electronic devices often contain several sub-circuits with its own voltage level requirement different than that supplied by the battery or an external supply (sometimes higher or lower than the supply voltage, and possibly even negative voltage). Additionally, the battery voltage declines as its stored power is drained. Switched DC to DC converters offer a method to increase voltage from a partially lowered battery voltage thereby saving space instead of using multiple batteries to accomplish the same thing.[edit] Conversion methods[edit] Electronic[edit] LinearLinear regulators...
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| Switched-mode power supply |
| 2008-03-10 00:37:22 |
A switched-mode power supply, switching-mode power supply or SMPS, is an electronic power supply unit (PSU) that incorporates a switching regulator. While a linear regulator maintains the desired output voltage by dissipating excess power in a "pass" power transistor, the SMPS rapidly switches a power transistor between saturation (full on) and cutoff (completely off) with a variable duty cycle whose average is the desired output voltage. The resulting rectangular waveform is low-pass filtered with an inductor and capacitor. The main advantage of this method is greater efficiency because the switching transistor dissipates little power in the saturated state and the off state compared...
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| Power over Ethernet |
| 2008-03-10 00:36:05 |
Power over Ethernet or PoE technology describes a system to transmit electrical power, along with data, to remote devices over standard twisted-pair cable in an Ethernet network. This technology is useful for powering IP telephones, wireless LAN access points, network cameras, remote network switches, embedded computers, and other appliances where it would be inconvenient, expensive (mains wiring must often be done by qualified and/or licensed electricians for legal or insurance reasons) or infeasible to supply power separately. The technology is somewhat comparable to POTS telephones, which also receive power and data (although analog) through the same cable. It works with an unmodified Ethernet cabling infrastructure.There are several general terms used t...
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| British telephone sockets |
| 2008-03-10 00:35:04 |
SocketsA fixed BT Master Socket front LJ 2/1A that does not allow disconnection of internal wiring with previous BT logo - surface mountedA fixed BT Master Socket front LJ 2/1A that does not allow disconnection of internal wiring with previous BT logo - surface mountedBT NTE 5 Linebox Socket which allows easy disconnection of the internal wiring shown with cable attached - surface mountedBT NTE 5 Linebox Socket which allows easy disconnection of the internal wiring shown with cable attached - surface mountedA domestic single British telephone line installation will have one master socket in the premises, which is provided by BT or another service provider. The master socket contains a high voltage surge protection (SP1) to suppress high voltage spikes etc...
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| Bell Labs |
| 2008-03-10 00:32:58 |
(also known as Bell Labs and formerly known as AT&T Bell Laboratories and Bell Telephone Laboratories) is part of the research and development organization of Alcatel-Lucent and previously the United States Bell System.Bell Laboratories is headquartered at Murray Hill, New Jersey, in the USA, and has research and development facilities throughout the world.Origin and historical locationsIn 1925 Western Electric Research Laboratories and part of the engineering department of AT&T were consolidated to form Bell Telephone Laboratories, Inc. as a separate entity. The first president of research was Frank B. Jewett, who stayed until 1940. Ownership of Bell Laboratories was evenly split between AT&T and Western Electric. Its principal work was to design and support the equipment Western Electric...
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| 8P8C |
| 2008-03-10 00:31:56 |
(8P8C) modular plugs and jacks are communications connectors. Under the same naming scheme, an 8P6C connector has eight positions, with six positions containing conductors, and a 6P6C connector has six positions, all containing conductors.These connectors are often referred to as RJ45 plugs and jacks. This is technically incorrect because the RJ45 standard specifies both the mechanical interface and a quite different wiring scheme than T568A/B, which is often used for Ethernet and telephones.An 8P8C modular connector has two forms: the male plug and the female jack or socket. Each has eight conductors. The 8P8C connector is probably best known for its use in Ethernet. Since about 2000, it is nearly universal as the type of connector used on a cable that carries a single Ethernet network, a...
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| RS-232 |
| 2008-03-10 00:30:59 |
RS-232 (Recommended Standard 232) is a standard for serial binary data signals connecting between a DTE (Data terminal equipment) and a DCE (Data Circuit-terminating Equipment). It is commonly used in computer serial ports. A similar ITU-T standard is V.24.ContentsScope of the standardThe Electronic Industries Alliance (EIA) standard RS-232-C[1] as of 1969 defines: * Electrical signal characteristics such as voltage levels, signaling rate, timing and slew-rate of signals, voltage withstand level, short-circuit behavior, maximum stray capacitance and cable length. * Interface mechanical characteristics, pluggable connectors and pin identification. * Functions of each circuit in the interface connector. * Standard subsets of interface circuits for selected telecom applications.Th...
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| Integrated Services Digital Network |
| 2008-03-10 00:29:41 |
Integrated Services Digital Network (ISDN), originally "Integriertes Sprach- und Datennetz" (German for "Integrated Speech and Data Net"), is a circuit-switched telephone network system, designed to allow digital transmission of voice and data over ordinary telephone copper wires, resulting in better voice quality than an analog phone. It offers circuit-switched connections (for either voice or data) in increments of 64 kbit/s. One of the major use cases is Internet access, where ISDN typically provides a maximum of 128 kbit/s (which cannot be considered to be a broadband speed). More broadly, ISDN is a set of protocols for establishing and breaking circuit switched connections, and fo...
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| Western Electric |
| 2008-03-10 00:27:13 |
HistoryIn 1856, George Shawk purchased an electrical engineering business in Cleveland, Ohio. In 1869, he became partners with Enos M. Barton and, later the same year, sold his share to inventor Elisha Gray. In 1872 Barton and Gray moved the business to Clinton Street, Chicago, Illinois and incorporated it as the Western Electric Manufacturing Company. They manufactured a variety of electrical products including typewriters, alarms and lighting and had a close relationship with the telegraph company Western Union to whom they supplied relays and other equipment.In 1875, Gray sold his interests to Western Union, including the caveat that he had filed against Alexander Graham Bell's patent application for the telephone. T...
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| Registered jack |
| 2008-03-10 00:25:39 |
A registered jack (RJ) is a standardized physical interface for connecting telecommunications equipment (commonly, a telephone jack) or computer networking equipment. The standard designs for these connectors and their wiring are named RJ11, RJ14, RJ45, etc. These interface standards are most commonly used in North America, though some interfaces are used world-wide.The physical connectors that registered jacks use are of the modular connector type, except RJ21X which is a 25-pair Amphenol connector. For example, RJ11 uses a 6 pin 2 conductor (6P2C) modular plug and jack.Naming confusionThere is much confusion over these connection standards. The six-position plug and jack commonly used for telephone line connections may be used for RJ11, RJ14 or even RJ25, all of which are actually names ...
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