Tuesday, November 2, 2010
pelancaran roket
Tuesday, April 20, 2010
IP ADDRESS
An Internet Protocol (IP) address is a numerical label that is assigned to devices participating in a computer network, that uses the Internet Protocol for communication between its nodes.[1] An IP address serves two principal functions: host or network interface identification and location addressing. Its role has been characterized as follows: "A name indicates what we seek. An address indicates where it is. A route indicates how to get there."[2]
The designers of TCP/IP defined an IP address as a 32-bit number[1] and this system, known as Internet Protocol Version 4 or IPv4, is still in use today. However, due to the enormous growth of the Internet and the resulting depletion of available addresses, a new addressing system (IPv6), using 128 bits for the address, was developed in 1995[3] and last standardized by RFC 2460 in 1998.[4] Although IP addresses are stored as binary numbers, they are usually displayed in human-readable notations, such as 208.77.188.166 (for IPv4), and 2001:db8:0:1234:0:567:1:1 (for IPv6).
The Internet Protocol also routes data packets between networks; IP addresses specify the locations of the source and destination nodes in thetopology of the routing system. For this purpose, some of the bits in an IP address are used to designate a subnetwork. The number of these bits is indicated in CIDR notation, appended to the IP address; e.g., 208.77.188.166/24.
As the development of private networks raised the threat of IPv4 address exhaustion, RFC 1918 set aside a group of private address spaces that may be used by anyone on private networks. They are often used with network address translators to connect to the global public Internet.
The Internet Assigned Numbers Authority (IANA), which manages the IP address space allocations globally, cooperates with five Regional Internet Registries (RIRs) to allocate IP address blocks to Local Internet Registries (Internet service providers) and other entities.
colour code
FFF FFF | CCC CCC | 999 999 | 666 666 | 333 333 | 000 000 | FFC C00 | FF9 900 | FF6 600 | FF3 300 | SWITCH TO DECIMAL RGB COLOR CODES | |||||
99C C00 | CC9 900 | FFC C33 | FFC C66 | FF9 966 | FF6 633 | CC3 300 | CC0 033 | ||||||||
CCF F00 | CCF F33 | 333 300 | 666 600 | 999 900 | CCC C00 | FFF F00 | CC9 933 | CC6 633 | 330 000 | 660 000 | 990 000 | CC0 000 | FF0 000 | FF3 366 | FF0 033 |
99F F00 | CCF F66 | 99C C33 | 666 633 | 999 933 | CCC C33 | FFF F33 | 996 600 | 993 300 | 663 333 | 993 333 | CC3 333 | FF3 333 | CC3 366 | FF6 699 | FF0 066 |
66F F00 | 99F F66 | 66C C33 | 669 900 | 999 966 | CCC C66 | FFF F66 | 996 633 | 663 300 | 996 666 | CC6 666 | FF6 666 | 990 033 | CC3 399 | FF6 6CC | FF0 099 |
33F F00 | 66F F33 | 339 900 | 66C C00 | 99F F33 | CCC C99 | FFF F99 | CC9 966 | CC6 600 | CC9 999 | FF9 999 | FF3 399 | CC0 066 | 990 066 | FF3 3CC | FF0 0CC |
00C C00 | 33C C00 | 336 600 | 669 933 | 99C C66 | CCF F99 | FFF FCC | FFC C99 | FF9 933 | FFC CCC | FF9 9CC | CC6 699 | 993 366 | 660 033 | CC0 099 | 330 033 |
33C C33 | 66C C66 | 00F F00 | 33F F33 | 66F F66 | 99F F99 | CCF FCC | CC9 9CC | 996 699 | 993 399 | 990 099 | 663 366 | 660 066 | |||
006 600 | 336 633 | 009 900 | 339 933 | 669 966 | 99C C99 | FFC CFF | FF9 9FF | FF6 6FF | FF3 3FF | FF0 0FF | CC6 6CC | CC3 3CC | |||
003 300 | 00C C33 | 006 633 | 339 966 | 66C C99 | 99F FCC | CCF FFF | 339 9FF | 99C CFF | CCC CFF | CC9 9FF | 996 6CC | 663 399 | 330 066 | 990 0CC | CC0 0CC |
00F F33 | 33F F66 | 009 933 | 00C C66 | 33F F99 | 99F FFF | 99C CCC | 006 6CC | 669 9CC | 999 9FF | 999 9CC | 993 3FF | 660 0CC | 660 099 | CC3 3FF | CC0 0FF |
00F F66 | 66F F99 | 33C C66 | 009 966 | 66F FFF | 66C CCC | 669 999 | 003 366 | 336 699 | 666 6FF | 666 6CC | 666 699 | 330 099 | 993 3CC | CC6 6FF | 990 0FF |
00F F99 | 66F FCC | 33C C99 | 33F FFF | 33C CCC | 339 999 | 336 666 | 006 699 | 003 399 | 333 3FF | 333 3CC | 333 399 | 333 366 | 663 3CC | 996 6FF | 660 0FF |
00F FCC | 33F FCC | 00F FFF | 00C CCC | 009 999 | 006 666 | 003 333 | 339 9CC | 336 6CC | 000 0FF | 000 0CC | 000 099 | 000 066 | 000 033 | 663 3FF | 330 0FF |
00C C99 | © 2006 VisiBone | 009 9CC | 33C CFF | 66C CFF | 669 9FF | 336 6FF | 003 3CC | 330 0CC | |||||||
00C CFF | 009 9FF | 006 6FF | 003 3FF |
straight cable cat5
Wow! After over 10 Years of working with cables, tools and connectors, and after keeping on top of our tool, cable, and connector suppliers, we have put it all together to formulate this system for the present a future of cabling components. What does all this mean to the consumer?Compatibility, Reliability, Dependability, ease of use and virtually fool-proof and repeatable results.
Due to an overwhelming response to our category 5 & 6 tutorial, and many requests for information and wiring diagrams of "straight through" and "crossover" (cross-pinned) patch cords, I have made this informational page and technical video. On this page, we will cover making patch cords, and other technical and non-technical issues relating to category 5 and 6 patching and connectivity from device to device. Below, you will find the diagrams for 568A, 568B, and crossover patch cables. I suggest that you read on, past the diagrams for some very useful and important information.
As always, there continues to be Controversies over standards and practices regarding the use and making of patch cords, and UTP cable in general. Please see our section below titled: "Controversies and Caveats : Category 5, 5E, and Cat 6 Patch Cables". I hope that you will find it interesting and informative.
cross cable cat5
How-to: Do it yourself Ethernet Crossover Cable | |
by: Larry Mingus Published: October 4, 1998 |
This how-to is for all of you that enjoy the DIY thing or have more time than money. It is far easier to buy a ready made cable but not near as fulfilling. Plus, there are those times when you need a cable now and can't get a ready made quick enough. You will need a length of network cable (UTP-Cat5), preferably a factory assembled straight through cable that comfortably reaches each computer. Be careful and measure accurately you would hate to find out that following the baseboard of the wall you end up two feet short. On the other hand you don't want to use a fifty foot cable to connect two computers ten feet apart. Ethernet does not like coiled up excess cable. Consider making the cable with enough slack to allow servicing the computer without needing to unplug the cable. The hardest part for most people will most likely be finding the RJ45 cable connectors. Check with your local computer stores that do network installations, most techs will give you a couple if you ask. Otherwise you will have to buy a five or ten pack. Make sure you get at least two, three is better. That way if you mess up you can just cut off the bad end and try again. Cut off the RJ45 connector from one end of the cable and prepare the end for the new RJ45 connector. I don't use measurements for stripping the cable end, I start by stripping at least 1 inch of the main cable insulation and then carefully trim the eight internal wires using the factory assembled end as a guide to the proper length. Just make sure that each wire is equal length and that the connector cable lock pinches the main cable insulation. You don't need any fancy crimping tools to make one cable, just one normal size screw driver and one small screwdriver with a blade the same thickness' of the brass conductors in the RJ45 connector. You may need a second pair of hands to help hold the cable and RJ45 connector while you or your helper secures the connector cable lock. It's a little tricky to get all the wires into the proper holes but with a little patience anyone can do it. When it comes time to securing the connector cable lock use the normal size screwdriver that fits into the connector cable lock slot. It doesn't take a lot of pressure to seat the cable lock just tap lightly until the cable is secure. Note: Make sure ALL wires are pushed completely into the connector before seating the connector cable lock. Once the connector cable lock is secure it's time to move on to seating the brass wire conductors. This is probably the most tricky part, each wire has a separate brass conductor that needs to be seated to make contact with the wire. Once again you will want a second pair of hands to hold the RJ45 connector while you or your partner carefully seats each of the brass conductors. Lightly tap each conductor down with the small thin screwdriver to just below the plastic ridge, use the factory assembled end of the cable as a guide for how deep to seat the brass conductors. Note: A pliers can be used to press down all the brass conductors at one time to the plastic ridges, then use the small thin blade screwdriver to finish seating to the proper recessed level. That's it, if everything went well you now have an Ethernet UTP Category 5 crossover cable.
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Crossover Cable | Straight Through Cable | |||
RJ-45 PIN | RJ-45 PIN | RJ-45 PIN | RJ-45 PIN | |
1 Rx+ | 3 Tx+ | 1 Tx+ | 1 Rc+ | |
2 Rc- | 6 Tx- | 2 Tx- | 2 Rc- | |
3 Tx+ | 1 Rc+ | 3 Rc+ | 3 Tx+ | |
6 Tx- | 2 Rc- | 6 Rc- | 6 Tx- |
Note: The standard connector view shown is color-coded for a straight thru cable Category 5 wiring standards: EIA/TIA 568A/568B and AT&T 258A define the wiring standards and allow for two different wiring color codes.
Only two pairs of wires in the eight-pin RJ-45 connector are used to carry Ethernet signals. Both 10BASE-T and 100BASE-T use the same pins, a crossover cablemade for one will also work with the other. *Note: Even though pins 4,5,7, and 8 are not used, it is mandatory that they be present in the cable.
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Monday, March 22, 2010
computer virus
A computer virus is a computer program that can copy itself[1] and infect a computer. The term "virus" is also commonly but erroneously used to refer to other types of malware, adware, and spyware programs that do not have the reproductive ability. A true virus can only spread from one computer to another (in some form of executable code) when its host is taken to the target computer; for instance because a user sent it over a network or the Internet, or carried it on a removable medium such as a floppy disk, CD, DVD, or USB drive. Viruses can increase their chances of spreading to other computers by infecting files on a network file system or a file system that is accessed by another computer.[2][3]
As stated above, the term "computer virus" is sometimes used as a catch-all phrase to include all types of malware, adware, and spywareprograms that do not have the reproductive ability. Malware includes computer viruses, worms, trojans, most rootkits, spyware, dishonest adware, crimeware, and other malicious and unwanted software, including true viruses. Viruses are sometimes confused with computer wormsand Trojan horses, which are technically different. A worm can exploit security vulnerabilities to spread itself automatically to other computers through networks, while a Trojan is a program that appears harmless but hides malicious functions. Worms and Trojans, like viruses, may harm a computer system's data or performance. Some viruses and other malware have symptoms noticeable to the computer user, but many are surreptitious and go unnoticed.