CS 407 Distributed System & Databases



WEEK # 3 - TRENDS IN DISTRIBUTED SYSTEMSDAY # 7Pervasive networking and the modern InternetThe modern Internet is a vast interconnected collection of computer networks of many different types, with the range of types increasing all the time and now including, for example, a wide range of wireless communication technologies such as WiFi, WiMAX, Bluetooth and third-generation mobile phone networks. The net result is that networking has become a pervasive resource and devices can be connected (if desired) at any time and in any place.The Internet is also a very large distributed system. It enables users, wherever they are, to make use of services such as the World Wide Web, email and file transfer.Mobile & Ubiquitous ComputingTechnological advances in device miniaturization and wireless networking have led increasingly to the integration of small and portable computing devices into distributed systems. These devices include:Laptop computers.Handheld devices, including mobile phones, smart phones, GPS-enabled devices,pagers, personal digital assistants (PDAs), video cameras and digital cameras.Wearable devices, such as smart watches with functionality similar to a PDA.Devices embedded in appliances such as washing machines, hi-fi systems, cars and refrigerators.Four Waves - Four ParadigmsMainframe computing (60’s-70’s)massive computers to execute big data processing applicationsvery few computers in the worldDesktop computing (80’s-90’s)one computer at every desk to help in business-related activitiescomputers connected in intranets to a massive global network (internet), all wiredMobile computing (90’s-00’s)a few devices for every person, small enough to carry arounddevices connected to cellular networks or WLANsUbiquitous computing (now)tens/hundreds of computing devices in every room/person, becoming “invisible” and part of the environmentWANs, LANs, PANs – networking in small spacesMobile ComputingMobile computing is the performance of computing tasks while the user is on the move, or visiting places other than their usual environment.In mobile computing, users who are away from their ‘home’ intranet (the intranet at work, or their residence) are still provided with access to resources via the devices they carry with them.Ubiquitous ComputingUbiquitous computing?(ubicomp) is an advanced computing concept where computing is made to appear everywhere and anywhere. In contrast to desktop computing, ubiquitous computing can occur using any device, in any location, and in any format. A user interacts with the computer, which can exist in many different forms - laptop, tablets, terminals, phones, etc. Ubiquitous computing = mobile computing + intelligent environment.What is the difference between Ubiquitous Computing and Cloud Computing?Ubiquitous computing refers to everyday objects becoming computing nodes, such as smart appliances. Cloud computing refers to running applications on the internet rather than locally. Services like Gmail and Flickr are examples of consumer cloud computing. Rather than reading mail or storing photos on their own machine, people can do these things on the internet instead.Difference between Ubiquitous and Mobile ComputingMobile computing: “on-the-go”, e.g., while sitting on a train; possibility of network connections remaining puting everywhere… OR computers everywhere…most of them invisible. From the point of view of distributed systems, there is no essential difference between mobile and ubiquitous computingWearable Computing:Devices attached to clothes, worn like watches, jewellery, etc.Context-Aware Computing:Device will automatically switch itself to “vibrate” instead of “ring” when it is in the cinema is a example of context-aware computing.WEEK # 3 - TRENDS IN DISTRIBUTED SYSTEMSDAY # 8Distributed Multimedia SystemsAn integrated communication, computing and information system that enables the processing, management, delivery, and presentation of synchronized multimedia information that the quality of service guarantees.Distributed multimedia system should be able to perform the same functions for continuous media types such as audio and video; that is, it should be able to store and locate audio or video files, to transmit them across the network (possibly in real time as the streams emerge from a video camera), to support the presentation of the media types to the user and optionally also to share the media types across a group of users.Benefits of Distributed Multimedia ComputingThe benefits of distributed multimedia computing are considerable in that a wide range of new (multimedia) services and applications can be provided on the desktop, including access to live or pre-recorded television broadcasts, access to film libraries offering video-on-demand services, access to music libraries, the provision of audio and video conferencing facilities and integrated telephony features including IP telephony or related technologies such as Skype.Distributed Multimedia ApplicationsInteractive television Video on demand, home shopping, video gamesTelecooperation Distance learning, telecommuting, videoconferencing Hypermedia Linked documents, digital library, on-line encyclopedia and etc.WebcastingWebcasting is an application of distributed multimedia technology. Webcasting is the ability to broadcast continuous media, typically audio or video, over the Internet. It is now commonplace for major sporting or music events to be broadcast in this way, often attracting large numbers of viewers (for example, the Live8 concert in 2005 attracted around 170,000 simultaneous users at its peak).Question:A user arrives at a railway station that she has never visited before, carrying a PDA that is capable of wireless networking. Suggest how the user could be provided with information about the local services and amenities at that station, without entering the station’s name or attributes. What technical challenges must be overcome?Answer:The user must be able to acquire the address of locally relevant information as automatically as possible. One method is for the local wireless network to provide the URL of web pages about the locality over a local wireless network.For this to work: (1) the user must run a program on her device that listens for these URLs, and which gives the user sufficient control that she is not swamped by unwanted URLs of the places she passes through; and (2) the means of propagating the URL (e.g. infrared or an 802.11 wireless LAN) should have a reach that corresponds to the physical spread of the place itself.WEEK # 3 – Lab Message Queuing Application DAY # 9 ................
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