1.4 Mobile Computing
Two major developments over the last decade have revolutionized the way people use their computers. First, advances in the miniaturization of circuits and components have made it possible to pack powerful processing units into portable laptops and more recently in palmtop computers. As a result, people from all walks of life have started carrying personal computers wherever they go. The second major development concerns computer communication and wireless networking of portable computers becoming a reality. These two developments have merged portable personal computing and communication to form the discipline of mobile computing [19-25].
Figure 1.7: Mobile computing.
Mobile computing is widely described as the ability to compute and communicate while on the move. This new emerging discipline has made it possible for people to get information from anywhere and at any time. Mobile computing means two separate and distinct concepts: mobility and computing. Computing denotes the capability to automatically carry out certain processing. Mobility, on the other hand, provides the capability to change a portable location during communication and computing. The main advantage of this mobility is the flexibility that it provides to the user. The user need not necessarily sit in front of his desktop, but can either move locally or even to faraway places.
1.4.1 Characteristics of Mobile Computing
A computing environment is said to be “mobile” when either the sender or receiver of information can move (mobile) while transmitting or receiving information. The following are the important characteristics of a mobile computing environment.
Ubiquity: The definition of ubiquity is “the state of being everywhere all the time.” Mobile computing allows a user to perform computation from anywhere, anytime. For example, a business executive can receive business notifications and issue business transactions as long he/she is in wireless coverage area.
Location awareness: A handheld device equipped with a global positioning system (GPS) can provide information about the current location of a user. Many applications ranging from strategic to personalized services require or get value additions with location-based services. For example, while a person is on the move, he/she may be on the lookout for car maintenance services available nearby. This can be very easily achieved through mobile computing. Of the numerous applications, a few example applications are traffic control, fleet management and emergency and security services.
Adaptation: Adaptation implies the ability of a system to adjust to bandwidth fluctuation without inconveniencing the user. In a mobile environment, adaptation is crucial because of intermittent disconnections and bandwidth fluctuations that arise due to handoff, obstacles, environmental noise, etc.
Broadcasting: Efficient delivery of data to hundreds of mobile users simultaneously is possible in the mobile environment due to the fundamental broadcast nature of the underlying communication.
Personalization: Services in the mobile environment can be tailored to the user’s profile. This is required to let users easily avail information with handheld devices. For example, a mobile user may need certain information from specific sources, which can be easily achieved through personalization.
1.4.2 Characteristics of Mobile Networks
A few important characteristics of a mobile network are the following:
Dynamic topologies: Since systems can be moved subjectively, the system topology may change capriciously.
Bandwidth constrained, variable capacity links: Connecting wireless devices all together brings down connection limits compared with their wired alternative. Likewise, because of issues, for example, multi-access, fading, commotion and impedance conditions, the data transfer capacity of the remote connections can change discretionarily with time.
Energy constrained operation: The nodes in a MANET rely on battery power source. Mobile node batteries are small and normally store a very limited amount of energy. Inefficient network operations, such as routing, network initialization, etc., can rapidly drain batteries. In this situation, the most essential basic system paradigm should be vitality preservation.
Limited physical security: Mobile networks are prone to many more types of security threats than fixed networks, mainly due to wireless transmissions and collaborative routing. There are increased possibilities of eavesdropping, spoofing, and DOS attacks in these networks. Also, nodes are vulnerable to capture and compromise.
1.5 Summary
The basics of cloud computing have been described in this introductory chapter. The chapter began with a description of the evolution of cloud computing, including the historical advancement of cloud and how different computer systems are linked to form a cloud infrastructure. The concept of grid computing and its architecture and also cluster computing and its architecture were discussed. This chapter also presented a comparison-based study of cluster, grid and cloud, and concluded with a discussion of mobile computing.
EXERCISES
1 What is cloud computing? How do you differentiate it from internet computing?
2 Differentiate between a tightly coupled and a loosely coupled system with examples.
3 Define the cluster of computer environment. How can the cluster be used for high availability purposes?
4 What are the benefits of cloud computing?
5 What is a cloud?
6 Explain the architecture of the cluster of computers with neat sketches.
7 What is computer grid? How does the concept of grid computing mimic the electric grid?
8 Differentiate between distributed computing and peer-to-peer computing. What are the major challenges in distributed computing and peer-to-peer computing?
9 Explain how the grid computing environment is deployed.
10 What is mobile computing? Explain the three-tier structure of the mobile computing environment.
11 Briefly
