Tag: the present time

Classic Design

They were the cominezos of the Diagrams in Computer science. Read more here: Royal Dutch Shell. The flow charts describe what operations and in which sequence they are required to solve a given problem. An organizational chart or flow chart is a representation that illustrates the sequence of the operations that will be realised to secure the solution of a problem. Contact information is here: Edward Jones. The data flow diagram (DFD) is one of the most important tools used by the systems analysts.

The use of the data flow diagrams as modeled tool of were popuralizado by Of Frame (1978) and Gane and Sarson (1979), through its methodologies of structured analysis of systems. They suggested the data flow diagram was used like first tool by the analysts of the system to model the components of system. These components are the processes of the system, the data used by those processes, all external organization that interacts with the system and the flows of information of the system. Now we will describe each one of the four parts that form a DFD a) – the processes show what the system does. Each process has one or more entering of data and produces one or more exits of data. They imagine with circles. b) – a file or data store is a deposit of data. The processes can introduce or recover in them.

Each data store imagines by a fine line and has a unique name. c) – the external organizations are outside the system, but they provide or they use data of this one. They are organizations on which the designer does not have control. d) – and but the important thing that they are the data flows that model the movements of information in the system and they imagine by lines that unite the components. The direction of the flow is indicated with shoots with an arrow, and the line with the name of the data flow. It is had to recognize that classic organizational charts or DFD were a little abstract, and thank heavens by the good of the designers who evolved of one more a clearer and concise way so that they did not give errors at the time of translating them to a programming language. Like advance to the following type of diagrams you dire who are called Organization-Relation Model and is what she comes using now to design applications, also calls diagrams E-R, and was a fundamental concept at the time of appearing ” The Clases” and ” Objetos” but all this to great I will leave it advance for a following delivery. Original author and source of the article.

Open Office

Great amount of licenses exists of free software and its agreement can be very diverse. Despite of general way we can divide the licenses in two great blocks according to its more important characteristics. First they would be those that do not impose any condition in his second redistribution (permissive licenses) and second they would be those that do yes it (robust licenses or copyleft). Copyleft initially was developed for the distribution of the computer science programs. Software, nowadays so known, as Linux, Open Office or FireFox were created like free programs under copyleft.

With time, copyleft has extended to very diverse scopes, besides the computer science one, also to music, the edition, the right, the art or the media. One of first and more known projects than restored the bases of the conditions for the licenses of copyleft was the project of free software devised by company GNU. It was in 1983 when Richard Stallman created a productive process of cooperation for the elaboration of a free operative program of any restriction derived from copyright. The project mainly consisted of the elaboration of a set of licenses that guaranteed that the software created by the equipment of Stallman stayed completely frees in all later versions. The participants in this process could use, share, modify or improve anyone of the free versions of this software being forced to put it at the disposal of the rest of the society without no restriction regarding their operation. Of this form he was wanted to prevent that once put to the service of all the community of users without no restriction somebody he could change these conditions. Unlike a program under the public dominion in which also changes can be realised, copyleft prevents that it turns somebody it into a privative program. In a software under the public dominion any person who introduced modifications in the same could distribute, it as own product, that is to say, the intermediary could break the chain of free use initiated by the author original and to begin to distribute the versions modified under its own copyright. In case of copyleft, whatever it uses the free program it tries and it to redistribute, with or without changes, it will have to grant to the following receiver the freedom to copy it or to modify it, guaranteeing at any moment the maintenance of these initial conditions.

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