Advance System Analysis Lecture 9 PDF

Lecture (9) Advance CH 5: Architecture Design d System Analysis Dr. Asmaa Mohamed  Less- commonly used Architectures Server-Based Architectures  Server-Based Architectures The very first computing architectures were server based, with the server (usually,...

Lecture (9) Advance CH 5: Architecture Design d System Analysis Dr. Asmaa Mohamed  Less- commonly used Architectures Server-Based Architectures  Server-Based Architectures The very first computing architectures were server based, with the server (usually, a central mainframe computer) performing all four application functions. The clients (usually, terminals) enabled users to send and receive messages to and from the server computer. Server-Based Architectures  Server-Based Architectures advantages Application software is developed and stored on the server, and all data are on the same computer. There is one point of control because all messages flow through the one central server. Software development and software administration are simplified because a single computer hosts the entire system (operating system and application software) Server-Based Architectures  Server-Based Architectures Disadvantages The fundamental problem with early server-based systems was that the server processed all the work in the system. As the demands for more and more applications and the number of users grew, server computers became overloaded and unable to quickly process all the users’ demands. Response time became slower, and IS managers were required to spend increasingly more money to upgrade the server computer Server-Based Architectures  Zero Client Server or Ultrathin client is a server-based computing model that is often used today in a virtual desktop infrastructure (VDI). VDI is an environment in which a desktop operating system such as Windows or Linux, is hosted on a centralized, remote server. End users’ data, as well as desktop images, are managed within what is called a “virtual machine”. Server-Based Architectures  Zero Client Server or Ultrathin client A Zero Client endpoint device is a small, powerful, piece of hardware that helps to cut down spending, power consumption, space, noise, lack of security, along with more benefits… when used within a VDI environment. A typical zero client device is a small box that connects a keyboard, mouse, monitor, and Ethernet connection to a remote server. The server hosts everything: the client’s operating system and all software applications. The server can be accessed wirelessly or with cable. Server-Based Architectures  Zero Client Server Benefits Power usage can be significantly reduced compared to fat client configurations. The devices used are much less expensive than PCs or even thin client devices. Since there is no software at the client device, there is no vulnerability to malware. The zero client computing model provides an efficient and secure way to deliver applications to end users. Administration is easy and multiple virtual PCs can be run on server class hardware in VDI environments, significantly reducing the number of physical PCs that must be acquired and maintained. the server-based zero-client model limits the non-business use of the client computer (e.g., no Facebook; no Farmville, etc.). Client-Based Architectures  Client-Based Architectures. With client-based architectures, the clients are microcomputers on a local area network, and the server is a server computer on the same network. The application software on the client computers is responsible for the presentation logic, the application logic, and the data access logic; the server simply provides storage for the data (Figure 8-5). Client-Based Architectures  Client-Based Architectures advantages This simple architecture often works very well in situations with low numbers of users or limited data access requirements  Client-Based Architectures problems. The fundamental problem in the client-based architecture is that all data on the server must travel to the client for processing. For example, suppose that the user wishes to display a list of all employees with company life insurance. All the data in the employee database must travel from the server, where the database is stored, over the network to the client, which then executes the query to find each record that matches the data requested by the user. In the client-based computing model, the data access logic is executed on the client system. Therefore, the entire database must be transmitted to the client before processing can take place. This can overload both the network and the power of the client computers. Advances in Architecture Configurations Advances in Architecture Configurations  Advances in Architecture Configurations. Two advances that are currently getting a lot of attention:  Virtualization  Cloud computing Virtualization  Virtualization: This term, in the computing domain, refers to the creation of a virtual device or resource, such as a server or storage device. In other words, virtualization is the process of creating a software-based version of something rather than a tangible one. There are three of these areas where virtualization is used most. These include Server virtualization, storage virtualization, and network virtualization.  Fore example, You may be familiar with this concept if you have partitioned your computer’s hard drive into more than one separate hard drive. While you only have one physical hard drive in your system, you treat each partitioned, “virtual” drive as if it is a distinct physical hard drive. Virtualization  Server virtualization: involves partitioning a physical server into smaller virtual servers. Software is used to divide the physical server into multiple virtual environments, called virtual or private servers. Virtualization  Capabilities of Server Virtualization It overcomes the primary limitation of the older style server-based architectures that were based on single, large, expensive, monolithic computers. Less hardware is required to provide a set of virtual servers as compared to equivalent physical servers, so costs are reduced. Virtualization  Storage virtualization: the pooling of physical storage from multiple network storage devices into what appears to be a single storage device that is managed from a central console.. Virtualization  Network virtualization is a method of combining the available resources in a network by splitting up the available bandwidth into channels, each of which acts independently from the others, and can be assigned or reassigned to a particular server in real-time.  A storage area network (SAN) uses storage virtualization to create a high-speed sub-network of shared storage devices. Cloud Computing Cloud Computing  Cloud Computing: The “cloud” in cloud computing can be defined as the set of hardware, networks, storage, services, and interfaces that combine to deliver aspects of computing as a service  Cloud services include the delivery of software, infrastructure, and storage over the Internet (either as separate components or a complete platform) based on user demand. Cloud Computing  Cloud computing can be implemented in three ways: Public Clouds: services are provided “as a service” over the Internet with little or no control over the underlying technology infrastructure, for example, Amazon, Google, Microsoft, IBM, Oracle, and others. Private clouds: offer activities and functions “as a service,” but are deployed over a company intranet or hosted data center. For example, Many medical offices, banking institutions, and other organizations who are required to meet federal and state guidelines for data controls use a private cloud. Hybrid clouds: combine the power of both public and private clouds. An example of a hybrid cloud solution is an organization that wants to keep confidential information secured on their private cloud, but make more general, customer-facing content on a public cloud. Public vs. Private Cloud computing Public vs. Private vs. Hybrid Cloud computing Cloud computing  Advantages of Cloud computing Scalability (or elasticity) : the cloud can scale up for periods of peak demand and scale down for times of less demand. cloud customers can obtain cloud resources in a straightforward fashion. Arrangements are made with the cloud service provider for a certain amount of computing, storage, software, process, or other resources. After using these resources, they can be released if no longer required. cloud services typically have standardized APIs (application program interfaces). This means that the services have standardized the way that programs or data sources communicate with each other. This capability lets the customer more easily create linkages between cloud services. The cloud computing model enables customers to be billed for resources as they are used. Usage of the cloud is measured, and customers pay only for resources used Cloud computing  Advantages of Cloud computing  Cloud computing  Cloud computing challenge Recently, Amazon, one of the prominent suppliers of cloud computing, experienced a catastrophic failure that affected hundreds of organizations that use Amazon’s cloud services to run their businesses. Therefore, organizations should be prepared to carefully structure their cloud computing arrangements and include redundancy in their applications so that the negative consequences of a catastrophic failure are minimized.