PERANG CYBER RI-AUSTRALIA
Perang cyber antara hacker Indonesia melawan hacker Australia telah dimulai. Hacker kedua negara sudah saling melakukan serangan Distributed denial of Service (DdoS)ke server-server negara lawan sejak pertengahan bulan ini.
Perihal saling serang ini diungkapkan Predator, seorang hacktivis dari kelompok hacker "Hiddenline" kepada detikcom, Kamis (28/11/2002). Menurutnya serangan DdoS hacker Australia ke sebuah ISP di Yogyakarta bisa jadi merupakan serangan balasan.
"Saya rasa itu mungkin balasan dari pihak Aussie atas aktivitas DdoS yang datang dari Yogyakarta.Anggota kami pertengahan bulan ini aktif menyerang 203 (prefiks nomor IP Australia - Red) secara DdoS", tulis Predator dalam emailnya.
Serangan tersebut menurut Preadator dilakukan dari Yogyakarta dan tercatat memiliki nomor IP dari daerah tersebut.
Seperti diberitakan detikcom sebelumnya, selama satu pekan terakhir, sebuah perusahaan internet service provider (ISP) di Yogyakarta berulang kali terkena serangan DdoS yang dilakukan melalui ISP Telstra Internet di Canberra, Australia.
Hacker tersebut melakukan serangan DdoS melalui port User Datagram Protocol (UDP). Akibat serangan ini, bandwith ISP tersebut menjadi penuh sesak dan para pelanggan tidak dapat melakukan akses internet sebagai mana mestinya.
Saling serang antara hacker Indonesia dan Australia dimulai dengan serangan mass defacing hacker Indonesia ke situs-situs internet Australia. Serangan cyber ini disulut aksi sweeping gaya Rambo yang dilakukan pihak kepolisian dan badan intelejen ASIO terhadap warga negara Indonesia di Australia akhir bulan lalu.
Perang cyber kali ini bukan yang pertama kali bagi kalangan hacker Indonesia. Pada 1998, sempat terjadi perang cyber melawan hacker-hacker Cina pasca kerusuhan Mei tahun itu. Pada 1999 terjadi perang cyber melawan Portugis sebelum jajak pendapat di Timor Timur.
Perang cyber melawan Portugis berubah menjadi perang cyber melawan Australia ketika negara tersebut mulai turut campur setelah terjadinya kerusuhan pasca jajak pendapat.
Isnin, 8 November 2010
PERANG CYBER
JENAYAH CYBER
JENAYAH tidak hanya berlaku di alam nyata sebaliknya dalam perkembangan teknologi maklumat yang semakin pantas dan sentiasa berubah setiap masa ia dapat berlaku hanya dengan menaip di papan kekunci komputer.
Bagaimanapun ramai pengguna komputer tidak tahu bagaimana mendapat maklumat atau perlindungan sekiranya berlaku sesuatu mencurigakan seperti pencerobohan ke atas komputer, laman web atau emel.
Pertama kali diperkenalkan pada 1997 dan dikenali sebagai Malaysian Computer Emergency Response Team (MyCert) di bawah kendalian MIMOS Berhad (MIMOS) bertujuan mengawal selia pengguna internet di Malaysia.
Bagaimanapun, pada 24 Januari 1998 MyCERT diberi peranan yang lebih luas dan dijadikan sebagai National ICT Security and Emergency Response Centre (NISER) untuk mengawal ICT negara.
NISER dirasmikan oleh Perdana Menteri Datuk Seri Abdullah Ahmad Badawi pada 10 April 2001. NISER kemudian dikeluarkan dari MIMOS dan dijadikan entiti berasingan dan dikenali sebagai CyberSecurity Malaysia pada Mac 2007.
Pemangku Ketua Pegawai Eksekutif CyberSecurity Malaysia, Lt Kol (B) Husin Jazri, berkata agensi di bawah Kementerian Sains Teknologi dan Inovasi (MOSTI) itu akan menjadi pusat rujukan pakar keselamatan siber kepada mana-mana agensi kerajaan lain dan syarikat swasta, termasuk orang perseorangan bagi mendapatkan khidmat nasihat berkaitan dengan keselamatan dan pencegahan jenayah di alam siber.
“CyberSecurity Malaysia beroperasi sebagai syarikat kerajaan bukan berlandaskan keuntungan dan berada di kawalselia MOSTI.
“Agensi ini juga bukan badan penguatkuasa, sebaliknya agensi teknikal yang boleh membantu pengguna internet menangani ancaman siber serta memberi khidmat nasihat dan bertindak sebagai biro aduan awam bagi pengguna internet.
“CyberSecurity Malaysia adalah agensi teknikal dan menjadi biro pengaduan kepada pengguna dalam menyelesaikan masalah keselamatan internet di Malaysia,’ katanya.
CyberSecurity Malaysia ialah pusat koordinasi setempat untuk keselamatan pengguna siber kebangsaan dan ditubuhkan dengan objektif untuk melindungi, membimbing, promosi di samping merangka strategi dalam menangani isu keselamatan siber di Malaysia.
Peranan CyberSecurity Malaysia membabitkan pencegahan jenayah di samping mempromosikan standard dan pengalaman terbaik keselamatan maklumat, membantu mangsa jenayah siber, juruperunding kepada Kerajaan dan mengurangkan pencerobohan ke atas sistem dan rangkaian teknologi maklumat di Malaysia.
Menerusi CyberSecurity Malaysia lima perkhidmatan diperkenalkan kepada orang ramai iaitu ‘Cyber999 atau Tindakbalas Kecemasan Komputer’, ‘Forensik Siber’, ‘Jaminan Keselamatan Maklumat’, ‘Pengurusan Keselamatan Maklumat ’ dan ‘Latihan dan Pembudayaan”.
Orang ramai yang berdepan dengan masalah keselamatan siber boleh mendapatkan khidmat daripada CyberSecurity yang beroperasi bermula jam 8.30 pagi hingga 5.30 petang hari Isnin hingga Jumaat. CyberSecurity Malaysia juga membuka komunikasi kecemasan 24 jam melalui emel, sms dan telefon.
Khidmat percuma ketika kecemasan diberikan dan orang ramai boleh menghubungi CyberSecurity Malaysia di alamat Level 7, Sapura@Mines, 7 Jalan Tasik, The Mines Resort City, 43300 Seri Kembangan, Selangor atau hubungi talian 03-89926888, faks 03-03-89453250, emelkan ke info@cybersecurity.org.my atau lawati laman web www.cybersecurity.org.my
Differencess between internet,intranet,extranet
Internet: Is now the World Wide Web (WWW) network of computers that is dispersedly managed with minimal restriction. It is what you have asked this question over.
Intranet: Operates much the same as the Internet but is restricted to a single corporate entity that has full control and management over it. Able to maximize restrictions over users.
Extranet: is an extension of an Intranet over the Internet for remote users. Typically it is heavily restricted for security reasons to a virtual private network (VPN) connection for Telecommuters or other offsite users.
Ethernet is the standard cable for computers to hook up to the network. It is also used for network devices (Routers, modems & switches) to interface with each other.
Ahad, 31 Oktober 2010
Selasa, 29 Jun 2010
Ring topology
A ring network is a network topology in which each node connects to exactly two other nodes, forming a single continuous pathway for signals through each node - a ring. Data travels from node to node, with each node along the way handling every packet.
Because a ring topology provides only one pathway between any two nodes, ring networks may be disrupted by the failure of a single link[1]. A node failure or cable break might isolate every node attached to the ring. FDDI networks overcome this vulnerability by sending data on a clockwise and a counterclockwise ring: in the event of a break data is wrapped back onto the complementary ring before it reaches the end of the cable, maintaining a path to every node along the resulting "C-Ring". 802.5 networks -- also known as IBM Token Ring networks -- avoid the weakness of a ring topology altogether: they actually use a star topology at the physical layer and a Multistation Access Unit (MAU) to imitate a ring at the datalink layer.
Many ring networks add a "counter-rotating ring" to form a redundant topology. Such "dual ring" networks include Spatial Reuse Protocol, Fiber Distributed Data Interface (FDDI), and Resilient Packet Ring.
Star topology
Star networks are one of the most common computer network topologies. In its simplest form, a star network consists of one central switch, hub or computer, which acts as a conduit to transmit messages.[1] Thus, the hub and leaf nodes, and the transmission lines between them, form a graph with the topology of a star. If the central node is passive, the originating node must be able to tolerate the reception of an echo of its own transmission, delayed by the two-way transmission time (i.e. to and from the central node) plus any delay generated in the central node. An active star network has an active central node that usually has the means to prevent echo-related problems.
The star topology reduces the chance of network failure by connecting all of the systems to a central node. When applied to a bus-based network, this central hub rebroadcasts all transmissions received from any peripheral node to all peripheral nodes on the network, sometimes including the originating node. All peripheral nodes may thus communicate with all others by transmitting to, and receiving from, the central node only. The failure of a transmission line linking any peripheral node to the central node will result in the isolation of that peripheral node from all others, but the rest of the systems will be unaffected. [2]
It is also designed with each node (file servers, workstations, and peripherals) connected directly to a central network hub, switch, or concentrator.
Data on a star network passes through the hub, switch, or concentrator before continuing to its destination. The hub, switch, or concentrator manages and controls all functions of the network. It is also acts as a repeater for the data flow. This configuration is common with twisted pair cable. However, it can also be used with coaxial cable or optical fibre cable.
Contents [hide]
1 Advantages
2 Disadvantages
3 References
4 See also
Bus topology
A bus topology connects each computer (nodes) to a single segment trunk (a communication line, typically coax cable, that is referred to as the 'bus'. The signal travels from one end of the bus to the other. A terminator is required at each to absorb the signal so as it does not reflect back across the bus. A media access method called CSMA/MA is used to handle the collision that occur when two signals placed on the wire at the same time. The bus topology is passive. In other words, the computers on the bus simply 'listen' for a signal; they are not responsible for moving the signal along.
Ahad, 20 Jun 2010
NETWORK ARCHITECTURE
Network architecture is the design of a communications network. It is a framework for the specification of a network's physical components and their functional organization and configuration, its operational principles and procedures, as well as data formats used in its operation.
In computing, the network architecture is a characteristics of a computer network. The most prominent architecture today is evident in the framework of the Internet, which is based on the Internet Protocol Suite.
In telecommunication, the specification of a network architecture may also include a detailed description of products and services delivered via a communications network, as well as detailed rate and billing structures under which services are compensated.
In distinct usage in distributed computing, network architecture is also sometimes used as a synonym for the structure and classification of distributed application architecture, as the participating nodes in a distributed application are often referred to as a network. For example, the applications architecture of the public switched telephone network (PSTN) has been termed the Advanced Intelligent Network. There are any number of specific classifications but all lie on a continuum between the dumb network (e.g., Internet) and the intelligent computer network (e.g., the telephone network). Other networks contain various elements of these two classical types to make them suitable for various types of applications. Recently the context aware network, which is a synthesis of the two, has gained much interest with its ability to combine the best elements of both.
TYPES OF NETWORK
PERSONAL AREA NETWORK
A personal area network (PAN) is a computer network used for communication among computer and different information technological devices close to one person. Some examples of devices that are used in a PAN are personal computers, printers, fax machines, telephones, PDAs, scanners, and even video game consoles. A PAN may include wired and wireless connections between devices. The reach of a PAN typically extends to 10 meters.[2] A wired PAN is usually constructed with USB and Firewire connections while technologies such as Bluetooth and infrared communication typically form a wireless PAN
LOCAL AREA NETWORK
A local area network (LAN) is a network that connects computers and devices in a limited geographical area such as home, school, computer laboratory, office building, or closely positioned group of buildings. Each computer or device on the network is a node. Current wired LANs are most likely to be based on Ethernet technology, although new standards like ITU-T G.hn also provide a way to create a wired LAN using existing home wires (coaxial cables, phone lines and power lines).[3]
Typical library network, in a branching tree topology and controlled access to resourcesAll interconnected devices must understand the network layer (layer 3), because they are handling multiple subnets (the different colors). Those inside the library, which have only 10/100 Mbit/s Ethernet connections to the user device and a Gigabit Ethernet connection to the central router, could be called "layer 3 switches" because they only have Ethernet interfaces and must understand IP. It would be more correct to call them access routers, where the router at the top is a distribution router that connects to the Internet and academic networks' customer access routers.
The defining characteristics of LANs, in contrast to WANs (Wide Area Networks), include their higher data transfer rates, smaller geographic range, and no need for leased telecommunication lines. Current Ethernet or other IEEE 802.3 LAN technologies operate at speeds up to 10 Gbit/s. This is the data transfer rate. IEEE has projects investigating the standardization of 40 and 100 Gbit/s.[4]
HOME AREA NETWORK
A home area network is a residential LAN which is used for communication between digital devices typically deployed in the home, usually a small number of personal computers and accessories, such as printers and mobile computing devices. An important function is the sharing of Internet access, often a broadband service through a CATV or Digital Subscriber Line (DSL) provider.
CAMPUS NETWORK
A campus network is a computer network made up of an interconnection of local area networks (LANs) within a limited geographical area. The networking equipments (switches, routers) and transmission media (optical fiber, copper plant, Cat5 cabling etc.) are almost entirely owned (by the campus tenant / owner: an enterprise, university, government etc.).
In the case of a university campus-based campus network, the network is likely to link a variety of campus buildings including; academic departments, the university library and student residence halls.
WIRE AREA NETWORK
A wide area network (WAN) is a computer network that covers a large geographic area such as a city, country, or spans even intercontinental distances, using a communications channel that combines many types of media such as telephone lines, cables, and air waves. A WAN often uses transmission facilities provided by common carriers, such as telephone companies. WAN technologies generally function at the lower three layers of the OSI reference model: the physical layer, the data link layer, and the network layer.
GLOBAL AREA NETWORK
A global area network (GAN) is a network used for supporting mobile communications across an arbitrary number of wireless LANs, satellite coverage areas, etc. The key challenge in mobile communications is handing off the user communications from one local coverage area to the next. In IEEE Project 802, this involves a succession of terrestrial WIRELESS local area networks (WLAN).[5]
ENTERPRISE PRIVATE NETWORK
An Enterprise Private Network is a network build by an enterprise to interconnect the various company sites (production sites, head offices, remote offices, shops etc.) in order to share computer resources over the network.
Sample EPN made of Frame relay WAN connections and dialup remote access.Beginning with the digitalisation of telecommunication networks started in the 70's in the USA (by AT&T) [6] and propelled by the growth in computer systems availability and demands private networks have been built for decades without the need to append the term private to them. The networks were operated over telecommunication networks and as per voice communications a certain amount of security and secrecy was expected and assumed.
But with the Internet in the 90's came a new type of network built over this Public infrastructure, using encryption to protect the data traffic from eaves-dropping (VPN). So the enterprise networks are now commonly referred to Enterprise Private Network in order to clarify that these are private networks (in opposition to public networks).
Virtual private network
Sample VPN used to interconnect 3 office and Remote usersA virtual private network (VPN) is a computer network in which some of the links between nodes are carried by open connections or virtual circuits in some larger network (e.g., the Internet) instead of by physical wires. The data link layer protocols of the virtual network are said to be tunneled through the larger network when this is the case. One common application is secure communications through the public Internet, but a VPN need not have explicit security features, such as authentication or content encryption. VPNs, for example, can be used to separate the traffic of different user communities over an underlying network with strong security features.
A VPN may have best-effort performance, or may have a defined service level agreement (SLA) between the VPN customer and the VPN service provider. Generally, a VPN has a topology more complex than point-to-point.
Internetwork
An Internetwork is the connection of two or more private computer networks via a common switching (OSI Layer 2) or routing technology (OSI Layer 3) and owned by separate entities (public or private). The result is called an internetwork. The Internet is an aggregation of many internetworks, hence its name was shortened to Internet.
Any interconnection between public, private, commercial, industrial, or governmental networks may also be defined as an internetwork or (more often) an extranet.
Internet
The Internet is a global system of interconnected governmental, academic, corporate, public, and private computer networks. It is based on the networking technologies of the Internet Protocol Suite. It is the successor of the Advanced Research Projects Agency Network (ARPANET) developed by DARPA of the U.S. Department of Defense. The Internet is also the communications backbone underlying the World Wide Web (WWW). The 'Internet' is most commonly spelled with a capital 'I' as a proper noun, for historical reasons and to distinguish it from other generic internetworks.
Participants in the Internet use a diverse array of methods of several hundred documented, and often standardized, protocols compatible with the Internet Protocol Suite and an addressing system (IP Addresses) administered by the Internet Assigned Numbers Authority and address registries. Service providers and large enterprises exchange information about the reachability of their address spaces through the Border Gateway Protocol (BGP), forming a redundant worldwide mesh of transmission paths.
Intranets and extranets
Intranets and extranets are parts or extensions of a computer network, usually a local area network.
An intranet is a set of networks, using the Internet Protocol and IP-based tools such as web browsers and file transfer applications, that is under the control of a single administrative entity. That administrative entity closes the intranet to all but specific, authorized users. Most commonly, an intranet is the internal network of an organization. A large intranet will typically have at least one web server to provide users with organizational information.
An extranet is a network that is limited in scope to a single organization or entity and also has limited connections to the networks of one or more other usually, but not necessarily, trusted organizations or entities (e.g., a company's customers may be given access to some part of its intranet creating in this way an extranet, while at the same time the customers may not be considered 'trusted' from a security standpoint). Technically, an extranet may also be categorized as a CAN, MAN, WAN, or other type of network, although, by definition, an extranet cannot consist of a single LAN; it must have at least one connection with an external network.
Overlay Network
An overlay network is a computer network that is built on top of another network. Nodes in the overlay can be thought of as being connected by virtual or logical links, each of which corresponds to a path, perhaps through many physical links, in the underlying network.
A sample overlay network: IP over SONET over OpticalNodes in the overlay can be thought of as being connected by virtual or logical links, each of which corresponds to a path, perhaps through many physical links, in the underlying network. For example, many peer-to-peer networks are overlay networks because they run on top of the Internet. Internet was built as an overlay on the telephone network [7].
Overlay networks have been around since the invention of networking when computer systems were connected over telephone lines using modem, before any data network existed.
Nowadays the Internet is the basis for many overlaid networks that can be constructed to permit routing of messages to destinations not specified by an IP address. For example, distributed hash tables can be used to route messages to a node having a specific logical address, whose IP address is not known in advance.
Overlay networks have also been proposed as a way to improve Internet routing, such as through quality of service guarantees to achieve higher-quality streaming media. Previous proposals such as IntServ, DiffServ, and IP Multicast have not seen wide acceptance largely because they require modification of all routers in the network. On the other hand, an overlay network can be incrementally deployed on end-hosts running the overlay protocol software, without cooperation from ISPs. The overlay has no control over how packets are routed in the underlying network between two overlay nodes, but it can control, for example, the sequence of overlay nodes a message traverses before reaching its destination.
For example, Akamai Technologies manages an overlay network that provides reliable, efficient content delivery (a kind of multicast). Academic research includes End System Multicast and Overcast for multicast; RON (Resilient Overlay Network) for resilient routing; and OverQoS for quality of service guarantees, among others.
Basic hardware components
All networks are made up of basic hardware building blocks to interconnect network nodes, such as Network Interface Cards (NICs), Bridges, Hubs, Switches, and Routers. In addition, some method of connecting these building blocks is required, usually in the form of galvanic cable (most commonly Category 5 cable). Less common are microwave links (as in IEEE 802.12) or optical cable ("optical fiber"). An Ethernet card may also be required.
Network interface cards
A network card, network adapter, or NIC (network interface card) is a piece of computer hardware designed to allow computers to communicate over a computer network. It provides physical access to a networking medium and often provides a low-level addressing system through the use of MAC addresses.
Repeaters
A repeater is an electronic device that receives a signal, cleans it of unnecessary noise, regenerates it, and retransmits it at a higher power level, or to the other side of an obstruction, so that the signal can cover longer distances without degradation. In most twisted pair Ethernet configurations, repeaters are required for cable that runs longer than 100 meters. Repeaters work on the Physical Layer of the OSI model.
Hubs
A network hub contains multiple ports. When a packet arrives at one port, it is copied unmodified to all ports of the hub for transmission. The destination address in the frame is not changed to a broadcast address.[8] It works on the Physical Layer of the OSI model.
Bridges
A network bridge connects multiple network segments at the data link layer (layer 2) of the OSI model. Bridges do send broadcasts to all ports except the one on which the broadcast was received. However, bridges do not promiscuously copy traffic to all ports, as hubs do, but learn which MAC addresses are reachable through specific ports. Once the bridge associates a port and an address, it will send traffic for that address to that port only.
Bridges learn the association of ports and addresses by examining the source address of frames that it sees on various ports. Once a frame arrives through a port, its source address is stored and the bridge assumes that MAC address is associated with that port. The first time that a previously unknown destination address is seen, the bridge will forward the frame to all ports other than the one on which the frame arrived.
Bridges come in three basic types:
Local bridges: Directly connect local area networks (LANs)
Remote bridges: Can be used to create a wide area network (WAN) link between LANs. Remote bridges, where the connecting link is slower than the end networks, largely have been replaced with routers.
Wireless bridges: Can be used to join LANs or connect remote stations to LANs.
Switches
A network switch is a device that forwards and filters OSI layer 2 datagrams (chunk of data communication) between ports (connected cables) based on the MAC addresses in the packets.[9] This is distinct from a hub in that it only forwards the frames to the ports involved in the communication rather than all ports connected. A switch breaks the collision domain but represents itself a broadcast domain. Switches make forwarding decisions of frames on the basis of MAC addresses. A switch normally has numerous ports, facilitating a star topology for devices, and cascading additional switches.[10] Some switches are capable of routing based on Layer 3 addressing or additional logical levels; these are called multi-layer switches. The term switch is used loosely in marketing to encompass devices including routers and bridges, as well as devices that may distribute traffic on load or by application content (e.g., a Web URL identifier).
Routers
A router is an internetworking device that forwards packets between networks by processing information found in the datagram or packet (Internet protocol information from Layer 3 of the OSI Model). In many situations, this information is processed in conjunction with the routing table (also known as forwarding table). Routers use routing tables to determine what interface to forward packets (this can include the "null" also known as the "black hole" interface because data can go into it, however, no further processing is done for said data).
Computer network
INTRODUCTION-A computer network allows sharing of resources and information among devices connected to the network. The Advanced Research Projects Agency (ARPA) funded the design of the Advanced Research Projects Agency Network (ARPANET) for the United States Department of Defense. It was the first operational computer network in the world.[1] Development of the network began in 1969, based on designs developed during the 1960s. For a history see ARPANET, the first network.
PURPOSE
Computer networks can be used for several purposes:
Facilitating communications. Using a network, people can communicate efficiently and easily via e-mail, instant messaging, chat rooms, telephony, video telephone calls, and videoconferencing.
Sharing hardware. In a networked environment, each computer on a network can access and use hardware on the network. Suppose several personal computers on a network each require the use of a laser printer. If the personal computers and a laser printer are connected to a network, each user can then access the laser printer on the network, as they need it.
Sharing files, data, and information. In a network environment, any authorized user can access data and information stored on other computers on the network. The capability of providing access to data and information on shared storage devices is an important feature of many networks.
Sharing software. Users connected to a network can access application programs on the network.
[edit] Network classification
The following list presents categories used for classifying networks.
CONNECTION METHOD
Computer networks can be classified according to the hardware and software technology that is used to interconnect the individual devices in the network, such as optical fiber, Ethernet, Wireless LAN, HomePNA, Power line communication or G.hn.
Ethernet uses physical wiring to connect devices. Frequently deployed devices include hubs, switches, bridges and/or routers. Wireless LAN technology is designed to connect devices without wiring. These devices use radio waves or infrared signals as a transmission medium. ITU-T G.hn technology uses existing home wiring (coaxial cable, phone lines and power lines) to create a high-speed (up to 1 Gigabit/s) local area network.
WIRED TECHNOLOGIES
Twisted pair wire is the most widely used medium for telecommunication. Twisted-pair wires are ordinary telephone wires which consist of two insulated copper wires twisted into pairs and are used for both voice and data transmission. The use of two wires twisted together helps to reduce crosstalk and electromagnetic induction. The transmission speed ranges from 2 million bits per second to 100 million bits per second.
Coaxial cable is widely used for cable television systems, office buildings, and other worksites for local area networks. The cables consist of copper or aluminum wire wrapped with insulating layer typically of a flexible material with a high dielectric constant, all of which are surrounded by a conductive layer. The layers of insulation help minimize interference and distortion. Transmission speed range from 200 million to more than 500 million bits per second.
Optical fiber cable consists of one or more filaments of glass fiber wrapped in protective layers. It transmits light which can travel over extended distances without signal loss. Fiber-optic cables are not affected by electromagnetic radiation. Transmission speed may reach trillions of bits per second. The transmission speed of fiber optics is hundreds of times faster than for coaxial cables and thousands of times faster than for twisted-pair wire.
WIRELESS TECHNOLOGIES
Terrestrial Microwave – Terrestrial microwaves use Earth-based transmitter and receiver. The equipment look similar to satellite dishes. Terrestrial microwaves use low-gigahertz range, which limits all communications to line-of-sight. Path between relay stations spaced approx. 30 miles apart. Microwave antennas are usually placed on top of buildings, towers, hills, and mountain peaks.
Communications Satellites – The satellites use microwave radio as their telecommunications medium which are not deflected by the Earth's atmosphere. The satellites are stationed in space, typically 22,000 miles (for geosynchronous satellites) above the equator. These Earth-orbiting systems are capable of receiving and relaying voice, data, and TV signals.
Cellular and PCS Systems – Use several radio communications technologies. The systems are divided to different geographic area. Each area has low-power transmitter or radio relay antenna device to relay calls from one area to the next area.
Wireless LANs – Wireless local area network use a high-frequency radio technology similar to digital cellular and a low-frequency radio technology. Wireless LANs use spread spectrum technology to enable communication between multiple devices in a limited area. An example of open-standards wireless radio-wave technology is IEEE 802.11b.
Bluetooth – A short range wireless technology. Operate at approx. 1Mbps with range from 10 to 100 meters. Bluetooth is an open wireless protocol for data exchange over short distances.
SCALE
Networks are often classified as local area network (LAN), wide area network (WAN), metropolitan area network (MAN), personal area network (PAN), virtual private network (VPN), campus area network (CAN), storage area network (SAN), and others, depending on their scale, scope and purpose. (e.g., Controller Area Network (CAN)) Usage, trust level, and access right often differ between these types of networks. For example, LANs tend to be designed for internal use by an organization's internal systems and employees in individual physical locations (such as a building), while WANs may connect physically separate parts of an organization and may include connections to third parties.
FUNCTIONAL RELATIONSHIP (network architecture)
Computer networks may be classified according to the functional relationships which exist among the elements of the network, e.g., active networking, client–server and peer-to-peer (workgroup) architecture.
NETWORK TOPOLOGY
Computer networks may be classified according to the network topology upon which the network is based, such as bus network, star network, ring network, mesh network, star-bus network, tree or hierarchical topology network. Network topology is the coordination by which devices in the network are arranged in their logical relations to one another, independent of physical arrangement. Even if networked computers are physically placed in a linear arrangement and are connected to a hub, the network has a star topology, rather than a bus topology. In this regard the visual and operational characteristics of a network are distinct. Networks may be classified based on the method of data used to convey the data, these include digital and analog networks.
Rabu, 2 Jun 2010
RAM(random acess memory)
Random-access memory (RAM) is a form of computer data storage. Today, it takes the form of integrated circuits that allow stored data to be accessed in any order (i.e., at random). "Random" refers to the idea that any piece of data can be returned in a constant time, regardless of its physical location and whether or not it is related to the previous piece of data.[1]
By contrast, storage devices such as magnetic discs and optical discs rely on the physical movement of the recording medium or a reading head. In these devices, the movement takes longer than data transfer, and the retrieval time varies based on the physical location of the next item.
The word RAM is often associated with volatile types of memory (such as DRAM memory modules), where the information is lost after the power is switched off. Many other types of memory are RAM, too, including most types of ROM and a type of flash memory called NOR-Flash.
penDRIve
Pen drives are classified as NAND style data storage devices. Equipped with a large amount of memory capacity, the pen drive is considered to be an improvement on both the older floppy drive disks and the more modern compact disks that are often used to copy data and reload the files on a different hard drive. Even a pen drive with a relatively low storage capacity tends to provide plenty of space for a number of files. The types of files that can be loaded onto a pen drive are all the common types that can be housed on any hard drive. This makes it possible for persons to copy photos, spreadsheets, word processing documents, movie clips, music tracks, and just about any other type of file.
Utilizing a pen drive is a simple task. One end of the drive is equipped with a USB connector at one end. The connector is inserted into the USB port on a desktop or laptop and activated. Once the pen drive is in place, it is possible to drop and drag files into the memory of the drive, or forward the files to the drive. The process is no more difficult than attaching files to an email or copying files onto a disk.
Because there are several different operating systems in common use today, there are various types of levels of the pen drive that are configured to work with each system. Even persons who are using an older operating system can usually find a pen drive that is compatible. As long as the desktop or laptop is constructed with a USB port, and the pen drive is compatible with the operating system, the pen drive will provide practical and easy transmission of data from one hard drive to another one in a matter of minutes.
CD rom
CD-ROM (pronounced /ˌsiːˌdiːˈrɒm/, an acronym of "compact disc read-only memory") is a pre-pressed compact disc that contains data accessible to, but not writable by, a computer for data storage and music playback, the 1985 “Yellow Book” standard developed by Sony and Philips adapted the format to hold any form of binary data.[1]
CD-ROMs are popularly used to distribute computer software, including games and multimedia applications, though any data can be stored (up to the capacity limit of a disc). Some CDs hold both computer data and audio with the latter capable of being played on a CD player, while data (such as software or digital video) is only usable on a computer (such as ISO 9660 format PC CD-ROMs). These are called enhanced CDs.
Although many people use lowercase letters in this acronym, proper presentation is in all capital letters with a hyphen between CD and ROM. It was also suggested by some,[who?] especially soon after the technology was first released, that CD-ROM was an acronym for "Compact Disc read-only-media", or that it was a more "correct" definition. This was not the intention of the original team who developed the CD-ROM, and common acceptance of the "memory" definition is now almost universal. This is probably in no small part due to the widespread use of other "ROM" acronyms such as Flash-ROMs and EEPROMs where "memory" is usually the correct term.[citation needed]
At the time of the technology's introduction it had far more capacity than computer hard drives common at the time, although the reverse is now true though some experimental descendants of it such as Holographic versatile disc may not have more space than today's biggest hard drive
Rabu, 5 Mei 2010
OPERATING SYSTEM FUNCTIONS
Operating System Functions
What is an Operating System
The operating system is the core software component of your computer. It performs many functions and is, in very basic terms, an interface between your computer and the outside world. In the section about hardware, a computer is described as consisting of several component parts including your monitor, keyboard, mouse, and other parts. The operating system provides an interface to these parts using what is referred to as "drivers". This is why sometimes when you install a new printer or other piece of hardware, your system will ask you to install more software called a driver.
What does a driver do?
A driver is a specially written program which understands the operation of the device it interfaces to, such as a printer, video card, sound card or CD ROM drive. It translates commands from the operating system or user into commands understood by the the component computer part it interfaces with. It also translates responses from the component computer part back to responses that can be understood by the operating system, application program, or user. The below diagram gives a graphical depiction of the interfaces between the operating system and the computer component.
Other Operating System Functions
The operating system provides for several other functions including:
System tools (programs) used to monitor computer performance, debug problems, or maintain parts of the system.
A set of libraries or functions which programs may use to perform specific tasks especially relating to interfacing with computer system components.
The operating system makes these interfacing functions along with its other functions operate smoothly and these functions are mostly transparent to the user.
OPERATING SYSTEM
Operating system
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Operating systems
Common features
Process management
Interrupts
Memory management
Virtual file system
Device drivers
Networking
Security
Graphical user interfaces
v • d • e
An operating system is the software on a computer that manages the way different programs use its hardware, and regulates the ways that a user controls the computer.[1][2] Operating systems are found on almost any device that contains a computer with multiple programs—from cellular phones and video game consoles to supercomputers and web servers. Some popular modern operating systems for personal computers include Microsoft Windows, Mac OS X, and Linux[3] (see also: list of operating systems, comparison of operating systems).
Because early computers were often built for only a single task, operating systems did not exist in their proper form until the 1960s.[4] As computers evolved into being devices that could run different programs in succession, programmers began putting libraries of common programs (in the form of computer code) onto the computer in order to avoid duplication and speed up the process. Eventually, computers began being built to automatically switch from one task to the next. The creation of runtime libraries to manage processing and printing speed came next, which evolved into programs that could interpret different types of programming languages into machine code. When personal computers by companies such as Apple Inc., Atari, IBM and Amiga became popular in the 1980s, vendors began adding features such as software scheduling and hardware maintenance.
An operating system can be divided into many different parts. One of the most important parts is the kernel, which controls low-level processes that the average user usually cannot see: it controls how memory is read and written, the order in which processes are executed, how information is received and sent by devices like the monitor, keyboard and mouse, and deciding how to interpret information received by networks. The user interface is the part of the operating system that interacts with the computer user directly, allowing them to control and use programs. The user interface may be graphical with icons and a desktop, or textual, with a command line. Another similar feature is an Application programming interface, which is a set of services and code libraries that let applications interact with one another, as well as the operating system itself. Depending on the operating system, many of these components may not be considered an actual part. For example, Windows considers its user interface to be part of the operating system, while many versions of
volatility
[edit] Volatility
Non-volatile memory
Will retain the stored information even if it is not constantly supplied with electric power. It is suitable for long-term storage of information. Nowadays used for most of secondary, tertiary, and off-line storage. In 1950s and 1960s, it was also used for primary storage, in the form of magnetic core memory.
Volatile memory
Requires constant power to maintain the stored information. The fastest memory technologies of today are volatile ones (not a universal rule). Since primary storage is required to be very fast, it predominantly uses volatile memory.
[e
Characteristics of Storage
A 1GB DDR RAM memory moduleStorage technologies at all levels of the storage hierarchy can be differentiated by evaluating certain core characteristics as well as measuring characteristics specific to a particular implementation. These core characteristics are volatility, mutability, accessibility, and addressibility. For any particular implementation of any storage technology, the characteristics worth measuring are capacity and performance.
Tertiary Storage
Tertiary storage
Large tape library. Tape cartridges placed on shelves in the front, robotic arm moving in the back. Visible height of the library is about 180 cm.Tertiary storage or tertiary memory,[3] provides a third level of storage. Typically it involves a robotic mechanism which will mount (insert) and dismount removable mass storage media into a storage device according to the system's demands; this data is often copied to secondary storage before use. It is primarily used for archival of rarely accessed information since it is much slower than secondary storage (e.g. 5–60 seconds vs. 1-10 milliseconds). This is primarily useful for extraordinarily large data stores, accessed without human operators. Typical examples include tape libraries and optical jukeboxes.
When a computer needs to read information from the tertiary storage, it will first consult a catalog database to determine which tape or disc contains the information. Next, the computer will instruct a robotic arm to fetch the medium and place it in a drive. When the computer has finished reading the information, the robotic arm will return the medium to its place in the library.
[edit] Off-line storage
Off-line storage is a computer data storage on a medium or a device that is not under the control of a processing unit.[4] The medium is recorded, usually in a secondary or tertiary storage device, and then physically removed or disconnected. It must be inserted or connected by a human operator before a computer can access it again. Unlike tertiary storage, it cannot be accessed without human interaction.
Off-line storage is used to transfer information, since the detached medium can be easily physically transported. Additionally, in case a disaster, for example a fire, destroys the original data, a medium in a remote location will probably be unaffected, enabling disaster recovery. Off-line storage increases general information security, since it is physically inaccessible from a computer, and data confidentiality or integrity cannot be affected by computer-based attack techniques. Also, if the information stored for archival purposes is accessed seldom or never, off-line storage is less expensive than tertiary storage.
In modern personal computers, most secondary and tertiary storage media are also used for off-line storage. Optical discs and flash memory devices are most popular, and to much lesser extent removable hard disk drives. In enterprise uses, magnetic tape is predominant. Older examples are floppy disks, Zip disks, or punched cards.
Secondary Storage
A hard disk drive with protective cover removed.Secondary storage (or external memory) differs from primary storage in that it is not directly accessible by the CPU. The computer usually uses its input/output channels to access secondary storage and transfers the desired data using intermediate area in primary storage. Secondary storage does not lose the data when the device is powered down—it is non-volatile. Per unit, it is typically also two orders of magnitude less expensive than primary storage. Consequently, modern computer systems typically have two orders of magnitude more secondary storage than primary storage and data is kept for a longer time there.
In modern computers, hard disk drives are usually used as secondary storage. The time taken to access a given byte of information stored on a hard disk is typically a few thousandths of a second, or milliseconds. By contrast, the time taken to access a given byte of information stored in random access memory is measured in billionths of a second, or nanoseconds. This illustrates the very significant access-time difference which distinguishes solid-state memory from rotating magnetic storage devices: hard disks are typically about a million times slower than memory. Rotating optical storage devices, such as CD and DVD drives, have even longer access times. With disk drives, once the disk read/write head reaches the proper placement and the data of interest rotates under it, subsequent data on the track are very fast to access. As a result, in order to hide the initial seek time and rotational latency, data are transferred to and from disks in large contiguous blocks.
When data reside on disk, block access to hide latency offers a ray of hope in designing efficient external memory algorithms. Sequential or block access on disks is orders of magnitude faster than random access, and many sophisticated paradigms have been developed to design efficient algorithms based upon sequential and block access . Another way to reduce the I/O bottleneck is to use multiple disks in parallel in order to increase the bandwidth between primary and secondary memory.[2]
Some other examples of secondary storage technologies are: flash memory (e.g. USB flash drives or keys), floppy disks, magnetic tape, paper tape, punched cards, standalone RAM disks, and Iomega Zip drives.
The secondary storage is often formatted according to a file system format, which provides the abstraction necessary to organize data into files and directories, providing also additional information (called metadata) describing the owner of a certain file, the access time, the access permissions, and other information.
Most computer operating systems use the concept of virtual memory, allowing utilization of more primary storage capacity than is physically available in the system. As the primary memory fills up, the system moves the least-used chunks (pages) to secondary storage devices (to a swap file or page file), retrieving them later when they are needed. As more of these retrievals from slower secondary storage are necessary, the more the overall system performance is degraded.
Primary Storage
[edit] Primary storage
Direct links to this section: Primary storage, Main memory, Internal Memory.
Primary storage (or main memory or internal memory), often referred to simply as memory, is the only one directly accessible to the CPU. The CPU continuously reads instructions stored there and executes them as required. Any data actively operated on is also stored there in uniform manner.
Historically, early computers used delay lines, Williams tubes, or rotating magnetic drums as primary storage. By 1954, those unreliable methods were mostly replaced by magnetic core memory, which was still rather cumbersome. Undoubtedly, a revolution was started with the invention of a transistor, that soon enabled then-unbelievable miniaturization of electronic memory via solid-state silicon chip technology.
This led to a modern random-access memory (RAM). It is small-sized, light, but quite expensive at the same time. (The particular types of RAM used for primary storage are also volatile, i.e. they lose the information when not powered).
As shown in the diagram, traditionally there are two more sub-layers of the primary storage, besides main large-capacity RAM:
Processor registers are located inside the processor. Each register typically holds a word of data (often 32 or 64 bits). CPU instructions instruct the arithmetic and logic unit to perform various calculations or other operations on this data (or with the help of it). Registers are technically among the fastest of all forms of computer data storage.
Processor cache is an intermediate stage between ultra-fast registers and much slower main memory. It's introduced solely to increase performance of the computer. Most actively used information in the main memory is just duplicated in the cache memory, which is faster, but of much lesser capacity. On the other hand it is much slower, but much larger than processor registers. Multi-level hierarchical cache setup is also commonly used—primary cache being smallest, fastest and located inside the processor; secondary cache being somewhat larger and slower.
Main memory is directly or indirectly connected to the central processing unit via a memory bus. It is actually two buses (not on the diagram): an address bus and a data bus. The CPU firstly sends a number through an address bus, a number called memory address, that indicates the desired location of data. Then it reads or writes the data itself using the data bus. Additionally, a memory management unit (MMU) is a small device between CPU and RAM recalculating the actual memory address, for example to provide an abstraction of virtual memory or other tasks.
As the RAM types used for primary storage are volatile (cleared at start up), a computer containing only such storage would not have a source to read instructions from, in order to start the computer. Hence, non-volatile primary storage containing a small startup program (BIOS) is used to bootstrap the computer, that is, to read a larger program from non-volatile secondary storage to RAM and start to execute it. A non-volatile technology used for this purpose is called ROM, for read-only memory (the terminology may be somewhat confusing as most ROM types are also capable of random access).
Many types of "ROM" are not literally read only, as updates are possible; however it is slow and memory must be erased in large portions before it can be re-written. Some embedded systems run programs directly from ROM (or similar), because such programs are rarely changed. Standard computers do not store non-rudimentary programs in ROM, rather use large capacities of secondary storage, which is non-volatile as well, and not as costly.
Recently, primary storage and secondary storage in some uses refer to what was historically called, respectively, secondary storage and tertiary storage.[1]
PURPOSE OF STORAGE
[edit] Purpose of storage
Many different forms of storage, based on various natural phenomena, have been invented. So far, no practical universal storage medium exists, and all forms of storage have some drawbacks. Therefore a computer system usually contains several kinds of storage, each with an individual purpose.
A digital computer represents data using the binary numeral system. Text, numbers, pictures, audio, and nearly any other form of information can be converted into a string of bits, or binary digits, each of which has a value of 1 or 0. The most common unit of storage is the byte, equal to 8 bits. A piece of information can be handled by any computer whose storage space is large enough to accommodate the binary representation of the piece of information, or simply data. For example, using eight million bits, or about one megabyte, a typical computer could store a short novel.
Traditionally the most important part of every computer is the central processing unit (CPU, or simply a processor), because it actually operates on data, performs any calculations, and controls all the other components.
Without a significant amount of memory, a computer would merely be able to perform fixed operations and immediately output the result. It would have to be reconfigured to change its behavior. This is acceptable for devices such as desk calculators or simple digital signal processors. Von Neumann machines differ in that they have a memory in which they store their operating instructions and data. Such computers are more versatile in that they do not need to have their hardware reconfigured for each new program, but can simply be reprogrammed with new in-memory instructions; they also tend to be simpler to design, in that a relatively simple processor may keep state between successive computations to build up complex procedural results. Most modern computers are von Neumann machines.
In practice, almost all computers use a variety of memory types, organized in a storage hierarchy around the CPU, as a trade-off between performance and cost. Generally, the lower a storage is in the hierarchy, the lesser its bandwidth and the greater its access latency is from the CPU. This traditional division of storage to primary, secondary, tertiary and off-line storage is also guided by cost per bit.
COMPUTER DATA STORAGE
Computer data storage
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1 GB of SDRAM mounted in a personal computer. An example of primary storage.
40 GB hard disk drive (HDD); when connected to a computer it serves as secondary storage.
160 GB SDLT tape cartridge, an example of off-line storage. When used within a robotic tape library, it is classified as tertiary storage instead.Computer data storage, often called storage or memory, refers to computer components, devices, and recording media that retain digital data used for computing for some interval of time. Computer data storage provides one of the core functions of the modern computer, that of information retention. It is one of the fundamental components of all modern computers, and coupled with a central processing unit (CPU, a processor), implements the basic computer model used since the 1940s.
In contemporary usage, memory usually refers to a form of semiconductor storage known as random-access memory (RAM) and sometimes other forms of fast but temporary storage. Similarly, storage today more commonly refers to mass storage — optical discs, forms of magnetic storage like hard disk drives, and other types slower than RAM, but of a more permanent nature. Historically, memory and storage were respectively called main memory and secondary storage. The terms internal memory and external memory are also used.
The contemporary distinctions are helpful, because they are also fundamental to the architecture of computers in general. The distinctions also reflect an important and significant technical difference between memory and mass storage devices, which has been blurred by the historical usage of the term storage. Nevertheless, this article uses the traditional nomenclature.
Khamis, 29 April 2010
what story???????????
Kepala dalam plastik
Oleh Mary Victoria Dass
2010/04/29 JOHOR BAHRU: “Jantung saya bagaikan tercabut apabila menemui bungkusan plastik hitam berisi kepala manusia,” kata pekerja syarikat kontraktor mengangkut sampah yang tidak menyangka rutin mengasingkan bahan buangan sejak beberapa tahun membawa kepada penemuan mayat seorang lelaki bogel dikerat enam.
DI SINI...tempat mayat lelaki yang dikerat enam ditemui. Lelaki belum dikenal pasti identitinya yang diceraikan kepala, badan, dua tangan dan dua kaki sebelum disumbat dalam tiga beg plastik sampah, ditemui di pusat pengumpulan sampah di Jalan Bakti, Kawasan Perindustrian Dato’ Onn, Larkin di sini, kira-kira jam 11.50 pagi semalam.
Difahamkan, anggota badan mangsa dicampak ke dalam tong sampah besar di sebuah kompleks beli-belah di Taman Perling di sini, sebelum diangkut ke pusat pengumpulan sampah berkenaan.
Pekerja yang mahu dikenali sebagai Kumar, 40-an, berkata mayat itu ditemui ketika dia bersama empat rakan sedang mengasingkan sampah di pusat pengumpulan sampah berkenaan.
Menceritakan pengalaman menakutkan itu, Kumar berkata, dia bertugas seperti biasa ketika membuka timbunan plastik sampah yang dibawa sebuah lori sebelum mendapati sebuah beg plastik mengandungi sesuatu yang keras dan lebih berat berbanding bahan buangan lain.
“Sebaik membuka beg plastik itu, saya nampak seolah-olah kepala patung. Bila diperiksa dengan betul baru saya sedar ia kepala manusia.
“Pengalaman pagi tadi (semalam) cukup mengerikan dan mengakibatkan saya trauma kerana tak sangka bungkusan itu mengandungi kepala lelaki berkulit cerah.
“Saya menggigil ketakutan tapi tetap beranikan diri memberitahu pengurus bertugas sebelum pemilik pusat pengumpulan sampah melaporkannya kepada polis,” katanya.
Sementara itu, Ketua Polis Daerah Johor Bahru Utara, Asisten Komisioner Ruslan Hassan, berkata beg plastik mengandungi anggota badan manusia yang dikerat itu diambil daripada tong sampah sebuah pusat beli-belah di Taman Perling, kira-kira jam 11.15 pagi.
“Hasil siasatan mendapati 80 peratus daripada tubuh mangsa masih lengkap. Selain kepala, kami menemui baki badan lelaki berkenaan dalam dua lagi beg plastik hitam,” katanya.
Menurutnya, mayat lelaki itu berkemungkinan warga asing berdasarkan keadaan fizikalnya.
Katanya, mayat berkenaan dihantar ke hospital untuk siasatan lanjut dan pihaknya percaya mangsa dibunuh di tempat lain sebelum dicampak ke tempat pembuangan sampah di belakang pusat beli-belah berkenaan.
“Siasatan mendapati lelaki terbabit berusia 20-an, berkulit cerah dan mungkin dibunuh dalam tempoh 24 jam sebelum ditemui.
“Kami masih berusaha mengenal pasti lelaki terbabit kerana tiada sebarang dokumen ditemui di tempat pembuangan sampah berkenaan.
“Kami juga akan menjalankan siasatan lanjut termasuk pergi ke kawasan pembuangan sampah di Perling untuk melihat sama ada terdapat kamera litar tertutup (CCTV) dipasang di sekitarnya bagi mengenal pasti identiti mangsa dan penjenayah yang terbabit,” katanya.
harian METRO
Tangisan suara halus
Oleh Nor Hazwani Hamat
2010/04/29 TANAH MERAH: “Saya terdengar suara jeritan bayi tapi tak tahu di mana. Sebaik membuka pintu rumah, saya terkejut apabila mendapati seorang bayi dibalut dengan kain selimut ditinggalkan di beranda rumah,” kata Sukma Abdullah, 53.
MALANG...bayi yang ditinggalkan Dia menemui seorang bayi lelaki di rumahnya di Jalan Wan Ahmad, dekat sini, kira-kira jam 12.30 tengah malam semalam.
Menurut Sukma, sebelum itu dia sedang bersiap untuk tidur sebelum dikejutkan dengan suara tangisan bayi.
Katanya, dia yang tinggal berseorangan agak takut kemungkinan diganggu ‘makhluk halus,’ namun sangkaannya meleset apabila dikejutkan dengan kehadiran bayi itu.
“Ketika itu, saya ingin masuk tidur tapi terdengar suara bayi. Saya takut dan turut menyangka tangisan itu adalah anak jiran yang mungkin sakit.
“Saya kemudian memeriksa dalam rumah sebelum membuka tingkap dekat pintu utama. Saya terkejut kerana ternampak ada ‘benda’ di beranda rumah sebelum memberanikan diri membuka pintu untuk melihat dari dekat. Saya terkejut mendapati ia seorang bayi,” katanya.
Sukma berkata, dia yang panik kemudian terus memberitahu jiran berhampiran sebelum menghubungi polis.
Katanya, dia turut hairan bagaimana ada individu boleh meninggalkan bayi di situ sedangkan terdapat ramai orang lalu lalang di depan rumahnya untuk mengunjungi pasar malam.
“Bayi itu ditinggalkan dalam keadaan sempurna dan sihat cuma terdapat sedikit kesan darah,” katanya.
Bayi seberat 3.3 kilogram itu dikatakan baru berusia dua hari dan masih bertali pusat.
Ketua Polis Daerah Tanah Merah, Deputi Superintendan Abdul Aziz Mahmud, berkata, pihaknya bergegas ke tempat kejadian sebaik menerima maklumat awam.
Katanya, bayi terbabit didapati dalam keadaan berbungkus dengan kain tuala dan selimut.
“Bayi terbabit kemudian dibawa ke Hospital Tanah Merah bagi mendapatkan rawatan segera di unit kecemasan sejurus kemudian.
“Setakat ini bayi itu ditempatkan di Wad Penjagaan Kanak-kanak dan suspek masih dicari,” katanya.
Menurutnya, polis turut meminta kerjasama pegawai Pejabat Pelajaran Daerah selain orang ramai untuk membantu siasatan.
“Semakan akan dibuat di sekolah menengah bagi mengenal pasti pelajar yang tidak hadir ke sekolah untuk tempoh beberapa hari dan beberapa klinik swasta sekitar daerah bagi membantu siasatan.
“Mereka mempunyai maklumat boleh menghubungi Inspektor Mardiana di talian 09-9557704,” katanya.
hOt nEws
H1N1: 16 pelajar MRSM Bentong masih dikuarantin
KUANTAN 28 April - Seramai 16 pelajar Maktab Rendah Sains Mara (MRSM) Bentong masih dikuarantin di bilik pengasingan sekolah tersebut setelah disahkan positif Influenza A (H1N1).
Pengerusi Jawatankuasa Kerajaan Tempatan, Alam Sekitar dan Kesihatan negeri, Datuk Hoh Khai Mun berkata, mereka terdiri daripada 10 pelajar perempuan dan enam lelaki.
"Tiga orang telah dirujuk ke hospital untuk pemeriksaan lanjut. Bagaimanapun, semua kes adalah stabil," katanya kepada pemberita ketika ditemui di luar persidangan Dewan Undangan Negeri Pahang di Wisma Sri Pahang di sini, hari ini.
Beliau berkata, sehingga semalam, sebanyak 50 kes kejadian kluster H1N1 dikesan di sekolah berkenaan, bagaimanapun 31 daripada pelajar terbabit dibenarkan pulang ke rumah bersama ibu bapa masing-masing.
Khai Mun berkata, Pejabat Kesihatan Bentong akan terus menjalankan pemantauan setiap hari terhadap pelajar dan kakitangan MRSM terbabit bagi mengesan sebarang kes baru, jika ada.
"Secara keseluruhan, kejadian kluster di MRSM Bentong adalah terkawal dan keadaan para pelajar terlibat adalah stabil," katanya.
Beliau memberitahu, sehingga semalam, sebanyak 142 kes H1N1 dilaporkan di negeri ini, selain 24 kejadian kluster melibatkan 11 sekolah dan 13 institusi lain.
Bagi membendung penularan penyakit tersebut katanya, Jabatan Kesihatan negeri mengambil langkah-langkah pencegahan dan kawalan seperti pemantauan penyakit serupa influenza (ILI), meningkatkan tahap kesiapsiagaan dan pendidikan kesihatan serta pemberian vaksin.
"Ketika ini, penyakit ini aktif balik melibatkan jangkitan tempatan. Kebanyakannya disebabkan kecuaian orang ramai yang tidak ambil berat tentang H1N1 dan langkah-langkah pencegahan penyakit tersebut," katanya.
Mengenai suntikan vaksin H1N1, beliau berkata, kumpulan sasar yang ingin mendapatkan suntikan tersebut dinasihati supaya terlebih dahulu membuat temu janji kerana suntikan tersebut hanya boleh diberikan apabila terdapat 10 orang pada satu-satu masa.
"Harap orang ramai faham bahawa vaksin datang dalam satu botol yang boleh menghasilkan 10 dos untuk 10 orang.
"Apabila botol vaksin dibuka, ia mesti dihabiskan," jelasnya.
Rabu, 28 April 2010
instalation office 2007
INTRODUCTION
This article describes how to install 2007 Microsoft Office features. It also de...This article describes how to install 2007 Microsoft Office features. It also describes how to repair the installed 2007 Office programs and features.
Note The information that is contained in this article is also available in Microsoft Office Help. For instructions about how to view this information in Help, see the "How to find out the information in Microsoft Office Help" section.
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MORE INFORMATIONHow to install individual 2007 Office featuresTypically, when you first try to u...How to install individual 2007 Office features
Typically, when you first try to use a feature that is not installed, the 2007 Office program installs the feature automatically. If the feature that you want is not automatically installed, follow these steps:
Exit all programs.
Click Start, and then click Control Panel.
If you are running Microsoft Windows Vista or Microsoft Windows 7, do the following:
Click Programs, and then click Uninstall a Program.
Click the name of the Microsoft Office Edition 2007 you want to change, and then click Change. In this item, Edition is a placeholder for the edition of Office that you installed.
Note In Classic view on Windows Vista or in Icon View on Windows 7, double-click Programs and Features, click the name of the Microsoft Office Edition 2007 you want to change, and then click Change.
If you are running Microsoft Windows XP, do the following:
Click Add or Remove Programs.
Click the name of the Microsoft Office Edition 2007 you want to change, and then click Change.
Note In Classic view, double-click Add or Remove Programs, click the name of the Microsoft Office Edition 2007 you want to change, and then click Change.
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How to repair problems in the installed 2007 Office programs and features
You can use either of the following methods to detect and to repair problems that are associated with installed Microsoft Office programs and features, such as registry settings and missing installation files. You cannot use these methods to repair personal files.
Method 1: Run Office Diagnostics from a 2007 Office program
Start the Office Diagnostics tool. To do this, use either of the following methods:
For a menu-based 2007 Office program, click Office Diagnostics on the Help menu.
For a ribbon-based 2007 Office program, follow these steps:
Click the Microsoft Office Button, and then click Program Options.
Note In this option, Program represents the name of the program.
In the Navigation Pane, click Resources.
Click Diagnose.
Click Continue.
Click Start Diagnostics.
If the Office Diagnostics tool identifies a problem, it tries to fix the problem.
When the Office Diagnostics tool finishes, click Close.
Note If you cannot run Office Diagnostics from a 2007 Office program, see the "How to run Office Diagnostics from the Start menu" in the Reference section.
Method 2: Run the Detect and Repair tool from Add or Remove Programs
Click Start, and then click Control Panel.
If you are running Microsoft Windows Vista or Microsoft Windows 7, do the following:
Click Programs, and then click Uninstall a Program.
Click the name of the Microsoft Office Edition 2007 you want to change, and then click Change.
Click Repair, and then click Continue.
Note In Classic view on Windows Vista or in Icon View on Windows 7, double-click Programs and Features. Click the name of the Microsoft Office Edition 2007 you want to change, and then click Change. Click Repair, and then click Continue.
If you are running Microsoft Windows XP, do the following:
Click Add or Remove Programs.
Click the name of the Microsoft Office Edition 2007 you want to change, and then click Change.
Click Repair, and then click Continue.
Note In Classic view, double-click Add or Remove Programs, click the name of the Microsoft Office Edition 2007 you want to change, and then click Change. Click Repair, and then click Continue.
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REFERENCESHow to run Office Diagnostics from the Start menuIn Microsoft Windows, click Sta...How to run Office Diagnostics from the Start menu
In Microsoft Windows, click Start, point to All Programs, point to Microsoft Office, point to Microsoft Office Tools, and then click Microsoft Office Diagnostics.
How to find out the information in Microsoft Office Help
Open Microsoft Office Program Help. To do this, press F1 or click the Microsoft Office Program Help button.
For example, in Office Word 2007, you can press F1 or click the Microsoft Office Word Help button at the upper-right of the Office Word 2007 window.
Type the keywords about the information that you want to search, and then click Search.
For example, you can type: how to repair the installed 2007 Office programs to search for your information.
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MORE INFORMATIONRelated topic: How to install and activate 2007 Microsoft Office system programs...Related topic:
How to install and activate 2007 Microsoft Office system programs (http://office.microsoft.com/en-us/help/HA101733401033.aspx)
2007 Office Solution Center (http://support.microsoft.com/ph/8753)
2007 Office installation and upgrad issues (http://support.microsoft.com/ph/8753#tab3)
2007 Microsoft Office Programs and Suites Setup Resource Center (http://support.microsoft.com/gp/officesuites2007setup)
928091 (http://support.microsoft.com/kb/928091/ ) Information about using 2007 Office suites and programs on a computer that is running another version of Office
Click the following links to find more options if this article cannot resolve your problem:
Microsoft Answer (http://answers.microsoft.com/en-us/default.aspx)
Troubleshooting for the 2007 Office release (http://technet.microsoft.com/en-us/library/cc298433.aspx)
2007 Office Help and How-to (http://office.microsoft.com/en-us/help/FX100485361033.aspx)
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Menformat hardisk
Tips dan Cara Memformat Ulang Hard Disk dan Menginstall Ulang OS Windows atau Linux pada Komputer PC / Laptop - Petunjuk Teknis
Mon, 19/06/2006 - 1:23pm — godam64
Masalah yang bersifat fatal dan parah bisa saja terjadi kapan dan di mana saja tidak memandang merk dan harga komputer pc / laptop anda. Terkadang komputer tidak bisa masuk ke windows akibat banyak hal seperti terkena virus, file booting hilang, bad sector, komputer lambat, komputer sering hang, salah seting dan berbagai masalah lainnya.
Jika berbagai cara sudah anda lakukan dan belum mendapatkan hasil yang memuaskan maka jalan pintas / singkat yang paling baik adalah dengan cara format ulang harddisk / hard drive yang ada di koputer pc / laptop anda. Pada tips ini akan diberikan beberapa langkah mudah yang dapat anda lakukan sendiri tetapi tidak secara mendetail. Bila anda butuh bimbingan anda bisa menanyakan di forum situs organisasi.org ini. Mudah-mudahan saya atau kawan lain dapat membantu anda.
A. Langkah dan Tahap Format Ulang Hard Disk
1. Back up / bekap file penting anda yang ada pada hardisk karena dengan format akan menghapus semua file yang ada di hard disk anda. Jika anda punya cd-rw drive atau dvd-rw drive anda bisa membakar file anda ke dalam cd atau dvd. Cara lain backup adalah dengan flash disk, disket floppy, disket zip, pindah file ke jaringan network lan atau internet pada komputer atau server lain dan lain-lain.
2. Setelah backup selanjutnya adalah membuat windows boot disk / rescue disk pada disket floppy 1.4 MB. Disket ini bertujuan untuk booting langsung ke disket tidak melalui harddisk anda. Istilahnya anda akan menggunakan os microsoft dos yang ada pada disket yang anda buat.
3. Ganti Setting Bios
Saat komputer dinyalakan anda harus langsung masuk ke tampilan bios untuk setting pilihan urutan boot. Caranya ketika komputer baru dinyalakan anda menekan dan menahan tombol delete sampai bios muncul di layar monitor komputer anda. Ganti urutan booting dengan urutan pertama floppy disk.
4. Format Hard Disk
Setelah bios diganti serta disave anda masukkan disket kemudian restart komputer anda. Nanti komputer anda akan otomatis boot dari disket tersebut dan pilih boot without cd-rom supaya proses booting bisa lebih cepat. Setelah masuk ke command prompt a:\ ketik format c: lalu tekan enter. Disesuaikan dengan jumlah partisi anda yang ada. Jika anda punya partisi 3 buah maka tambah perintah format d: dan format e:. Tips dan cara mempartisi hard disk mungkin bisa anda cari di kotak search di sebelah kiri halaman artikel ini. Jika format telah selsesai beri nama drive tersebut sesuai selera anda. Jika semua beres dan berjalan lancar maka proses format ulang telah selesai. Kini harddisk anda menjadi seperti baru kembali.
B. Langkah dan Tahap Install Ulang OS Windows dan Linux
1. Install Windows 98 / 2000 / ME / XP / Vista / Linux
Langkah pertama dalam mengistall ulang operating system pada komputer pc atau laptop anda adalah booting ulang ke disket anda dan pilih support cd-rom device. Setelah keluar command prompt lalu anda masukkan cd instalasi os anda sesuai selera anda. Kemudian cari drive cd-rom atau dvd-rom anda dengan mengetik d: atau e: dan lain sebagainya sesuai lokasi drive cd atau dvd rom anda. Setelah ketemu anda kemudian cari file setup.exe dengan perintah cdnama folfer untuk masuk ke dalam folder. Perintah cd.. untuk mundur satu folder level. perintah dir atau dir/w atau dir/p untuk melihat list file yang ada pada folder tersebut. Kalau sudah ketemu maka jalankan setup.exe atau install.exe dengan mengetik nama file tersebut lalu tekan tombol enter satu kali saja. Langkah berikutnya anda tinggal mengikuti perintah yang ada pada installasi cd atau dvd os.
2. Setting Settingan Boot pada Bios
Setelah install ulang windows atau linux selesai, maka keluarkan disket flopyy 1,4 anda dan masuk kembali ke menu bios setelah restart ulang. Pilih IDE-0 sebagai first boot. Floppy bisa anda seting menjadi boot kedua dan cd-rom menjadi boot ketiga. Anda bebas menentukannya sesuai dengan keinginan anda. Sehabis itu direstart ulang kembali.
3. Install Driver dan Software
Jika sudah berhasil masuk ke tampilan windows atau linux awal, selanjutnya anda nginstall driver untuk sound card, printer, scanner, kabel data, dan sebagainya sesuai hardware yang ada. Anda harus mencari dan memiliki sendiri driver tersebut. Setiap jenis komputer memiliki driver yang berbeda. Biasanya anda akan diberi cd driver saat anda membeli komputer atau hardware lainnya. Tanpa driver maka peralatan yang terhubung pada komputer laptop atau pc tidak dapat berjalan sebagaimana mestinya.
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 the topology 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.
Selasa, 20 April 2010
DOING THE DEED
Baby steps... 1) - Start by stripping off about 2 inches of the plastic jacket off the end of the cable. Be very careful at this point, as to not nick or cut into the wires, which are inside. Doing so could alter the characteristics of your cable, or even worse render is useless. Check the wires, one more time for nicks or cuts. If there are any, just whack the whole end off, and start over.
2) - Spread the wires apart, but be sure to hold onto the base of the jacket with your other hand. You do not want the wires to become untwisted down inside the jacket. Category 5 cable must only have 1/2 of an inch of 'untwisted' wire at the end; otherwise it will be 'out of spec'. At this point, you obviously have ALOT more than 1/2 of an inch of un-twisted wire, but don't worry - well take care of that soon enough.
3) - Up to this point, things have been pretty easy. Things will get a little bit tricky here, but don't worry, we'll get through this together. We are at a point in this article where a decision needs to be made. You need to decide which end of the cable you are making at this point in time. If you are making your cable from scratch like I am doing while writing this article, you have 2 end jacks, which must be installed on your cable. If you are using a pre-made cable, with one of the ends whacked off, you only have one end to install - the crossed over end. Below are two diagrams, which show how you need to arrange the cables for each type of cable end. Decide at this point which end you are making and examine the associated picture below.
568a - standard end(you will need one of the ends onyour cable to look like this)
Crossed over end wire pattern(you will want the other end to looklike this) Begin to untwist the twisted exposed wires on your cable. Use caution so that you do not untwist them down inside the jacket. Once you have all the wires untwisted begin to arrange them in the proper order based on the pictures above. This stage can be a pain in the ass, especially some of the middle wires. Once you get all the wired arranged in the proper order, make sure your wire cutters are within reach then grasp them right at the point where they enter the jacket. Make sure you keep them in the proper order! Grab your cutters now. Line them up along your prepared wires about 1/2 inch above the jacket. Be sure at this point that you are both 1/2 inch above the jacket, and that your cutters are aligned straight across the wires. You want to make a clean cut here - also make sure you don't let go of that jacket / wires!
4) - Don't worry. From this point forward things get a lot easier. Grab your jack, and begin to slide the wires into the jack. Once you get to the point where the jacket begins to enter the jack things might get a little tough, but just have some patience and hold onto those wires. It will fit in there just fine. Once it is in as far as it will go the wires should extend almost to the front of the jack, and about 3/8 of an inch of the jacket will be inside the jack. Like the pictures below.
5) - Grab those crimpers - because not all crimpers are exactly the same your pictures may not match exactly what you see below. Be sure to keep a good grip on that jack and the cable. Insert the jack into the crimper. It should only go in one way, so you don't have a whole lot to worry about inserting it. Begin to compress those crimpers. You will more than likely hear a clicking sound. Keep squeezing. If you try to let go to early, nothing will happen. They will not release. Keep going until they stop clicking / stop moving all together. At this point, you should be able to let go of the jack, and the crimpers. The crimpers should release now leaving you with a crimped jack. If the crimpers do not release, you probably are a wimp and didn't press hard enough. Go ask your mom to help you at this point. She can probably finish what you started.
Insert the jack into the crimper
Crimp it! Crimp it good! 6) - It's time to examine what we have done. If you look at the end of the jack (distal), you should see that the copper connectors should not be pressed down into the wires. Toward the back of the jack (where the jacket meets the jack) it should be crimped securely holding the jacket / cable in the jack. If something has gone wrong, don't worry, its not the end of the world. Grab those cutters, and just whack the whole jack off and start back at step 1 (a pain in the ass I know, but its better to have a cable that works, than to spend hours trouble shooting your PC trying to figure out why you can't see the other machine). If everything is cool, all you have to do now is make the other end of the cable (unless you are using a pre-fab cable and have whacked one of the ends off), so go back to step one, and make the other end now.
