Client/server computing

As network connectivity improved within the PC operating systems, client/server computing became possible. Instead of performing all of the work on a single, multi-user computer, you could now distribute the work across many computers. In the client/server model, adding a PC to the network increases the overall processing power of the system. The... 

Davis, T, Ed., Securing Client/Server Computer Networks, McGraw-Hill, New York, 1996. Edwards, J., 3-Tier Client/Server at Work, Rev. Ed., John WUey Sons, New York, 1999. Menasce, D. A., Almeida, V. A. F., and Dowdy, L. W, Capacity Planning and Performance Modeling From Mainframes to Client-Server Systems, Prentice HaU, Englewood Cliffs, NJ, 1994. 

With the rapid development of application tools a proven hardware policy has been what is known as client-server computing. All servers are open system large or mini computers (e.g. IBM-AIX) and client computers are largely personal computers (PCs). 

There are some RPC servers running on Internet hosts which accept client requests to perform chemical computation services. This access path is typically much faster than offering similar services for example via the WWW, but locally installed software which speaks the RPC protocol of the application is necessary. An example of client-server computing for chemical applications using RPC is shown in Figure 1. Here a molecule editor (part of the CACTVS package ) acts as a client to a 3D-coordinate generation server if the output structure file is a 3D format. 

D. Dewire, Client Server Computing , McGraw Hill, 1993. 

A hands-on experience with the method is possible via the SPINUS web service [48. This service uses a client-server model. The user can draw a molecular structure within the web browser workspace (the client), and send it to a server where the predictions are computed by neural networks. The results are then sent back to the user in a few seconds and visualised with the same web browser. Several operations and different types of technology arc involved in the system ... 

Clerici s solution, 24 632 Click chemistry, 2 222 26 788 Client-server (personal computer) distributed control system configuration, 20 670 Clinafloxacin, 22 220, 223, 224 Clinch River fast-breeder plant (CRFBP), 27 587... 

Note As is often the case, the HPLC system will be under computer control, which is likely to be part of a data-handling system. Since the data generated from the OQ hardware tests typically require chromatographic data handling, the data-handling software should be validated beforehand. The data-handlingfLC control software installation and IQ/OQ implementation, which are not addressed in this chapter, may take a considerable amount of time. This is often the case since this process typically involves an initial client/server implementation. 

There are inevitable interfaces between the application areas of the various sets of procedures and the computer systems to which they apply, as indicated in Figure 3.3. Client-server technology is typically the deciding factor in determining whether control system and laboratory application projects would be better served by IT system procedures. Another example might be that robotic systems used to automate laboratories would be better served by control system procedures. 

Good Practice for the use of computer systems in laboratory applications is now well established and is based on many years of experience. LIMS is simply another use of the power and flexibility of client/server or browser-accessed computerized systems. Therefore, it may be validated in a similar manner to other systems utilized within the pharmaceutical industry. Specifically, LIMS is... 

Database applications can be installed on stand-alone PCs, host computers, or may have client server architecture. The hardware platform supporting the application requires qualification. Hardware testing (Installation Qualification) should include ... 

Client-Server Architecture. A computer architecture in which a "server" computer (usually a larger and faster machine at a central location) runs programs that communicate over a network with numerous workstations or "client" machines that reside in offices and laboratories. The server computer performs heavy duty computing tasks such as database searching and molecular and data modeling, in response to commands from the users of the client comvuters. It then communicates the results back to the client machines. There, depending on whether the client is "thick" (a... 

Multi-tier Architecture. An expansion of a client-server architecture to include a middle layer of software. The middle tier may run on a computer different from either the client or server computers. The middle tier isolates the client and server programs, so that changes in either of them do not require corresponding changes in the other. The middle tier acts as to receive, authenticate, and transform data as it passes between client and server computers. To make middle tier software easy to change and maintain, it is often written in Java, a modem object-oriented computer language that is available free on most of today s computer platforms. 

Networked computer systems with multiple computers and peripherals. Examples are servers for common printing and data storage or client/server networks where the operating system and application software are loaded on the server and can be executed on the client computer. Another example is a laboratory information management system (LIMS) for collection and management of data from multiple computers. 

Our project has made extensive use of distributed computing, thanks to the Berkeley Open Infrastructure for Network Computing, BOINC (boinc.berkeley.edu) [33]. The client-server organization of BOINC is described elsewhere [33]. Here, we limit ourselves to a brief overview of features specific to our Proteins Home project. 

Nowadays, immersive multi-screen displays hke CAVEs are driven by off-the-shelf PC clusters with consumer graphics cards instead of multipipe, shared memory graphics computers. This reduces the costs for IVR infrastructure dramatically. VR toolkits supporting PC clusters must inherently have a distributed software architecture, and data synchronization is an issue in such frameworks. Besides a client-server approach, where the scenegraph is distributed over the cluster nodes, a master-slave approach is most often... 

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