Difference between revisions of "CSC103: DT's Notes 1"
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[http://www.imdb.com/title/tt0348121/ '''Steamboy'''], a Japanese animé by director Katsuhiro Ohtomo (who also directed ''Akira'') is interesting in more than the story of a little boy who is searching for his father, a scientist who has discovered a secret method for controlling high pressured steam. What is interesting is that the movie is science fiction taking place not in the future, but in middle of the 19th century, in a world where steam progress and steam machines are much more advanced than they actually were at that time. One can imagine that some events, and some discoveries where made in the world portrayed in the animated film, and that technology evolved in quite a different direction, bringing with it new machines, either steam-controlled tank-like vehicles, or ships, or flying machines. | [http://www.imdb.com/title/tt0348121/ '''Steamboy'''], a Japanese animé by director Katsuhiro Ohtomo (who also directed ''Akira'') is interesting in more than the story of a little boy who is searching for his father, a scientist who has discovered a secret method for controlling high pressured steam. What is interesting is that the movie is science fiction taking place not in the future, but in middle of the 19th century, in a world where steam progress and steam machines are much more advanced than they actually were at that time. One can imagine that some events, and some discoveries where made in the world portrayed in the animated film, and that technology evolved in quite a different direction, bringing with it new machines, either steam-controlled tank-like vehicles, or ships, or flying machines. | ||
| − | For computers, we can make the same observation. The reason our laptops today are designed the way they are is really the result of happy accidents in some ways. The way computers are designed, for example, with one processor (more on multi-core processors later), a system of busses, and memory where both data and programs reside side-by-side hasn't changed since '''John von Neumann''' wrote his (incomplete and never officially published) ''First Draft of a Report on the EDVAC,''<ref name="EDVAC | + | For computers, we can make the same observation. The reason our laptops today are designed the way they are is really the result of happy accidents in some ways. The way computers are designed, for example, with one processor (more on multi-core processors later), a system of busses, and memory where both data and programs reside side-by-side hasn't changed since '''John von Neumann''' wrote his (incomplete and never officially published) ''First Draft of a Report on the EDVAC,''<ref name="edvac">John von Neumann. First Draft of a Report on the EDVAC. IEEE Ann. Hist. Comput. 15, 4 (October 1993), 27-75.</ref> article, in June of 1945. |
One can argue that if von Neumann hadn't written this report, we may have followed somebody else's brilliant idea for putting together a machine working with electricity, where information is stored and operated on in binary form. Our laptop today could be using a different architecture, and programming them might be a totally different type of problem solving. | One can argue that if von Neumann hadn't written this report, we may have followed somebody else's brilliant idea for putting together a machine working with electricity, where information is stored and operated on in binary form. Our laptop today could be using a different architecture, and programming them might be a totally different type of problem solving. | ||
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But there is another subtlety here. Not all numbers are instructions. Just as in our games some numbers corresponded to sentences and others words that needed to be added at end of sentences ("did you like", "homework" for example), some numbers represent actions, while others are just regular numbers. When the processor starts absorbing the contents of memory cells, it assumes that the first number it's going to get is an ''instruction''. An instruction is usually followed by a ''datum''. A program is thus a collection of instructions and data. | But there is another subtlety here. Not all numbers are instructions. Just as in our games some numbers corresponded to sentences and others words that needed to be added at end of sentences ("did you like", "homework" for example), some numbers represent actions, while others are just regular numbers. When the processor starts absorbing the contents of memory cells, it assumes that the first number it's going to get is an ''instruction''. An instruction is usually followed by a ''datum''. A program is thus a collection of instructions and data. | ||
| − | Thinking of the memory as holding binary numbers that can be instructions or data, and that are organized in a logical way so that the processor always knows which is which was first conceived by '''John von Neumann''' in a famous report he wrote in 1945 titled "[http://cs.smith.edu/dftwiki/images/f/f8/VonNewmannEdvac.pdf First Draft of a Report on the EDVAC]" <ref name="edvac" | + | Thinking of the memory as holding binary numbers that can be instructions or data, and that are organized in a logical way so that the processor always knows which is which was first conceived by '''John von Neumann''' in a famous report he wrote in 1945 titled "[http://cs.smith.edu/dftwiki/images/f/f8/VonNewmannEdvac.pdf First Draft of a Report on the EDVAC]" <ref name="edvac" />. This report was not officially published until 1993, but circulated among the engineers of the time and his recommendations for how to design a computing machines are still the base of today's computer design. In his report he suggested that computers should store the code and the data in the same medium, which he called ''store'' at the time, but which we refer to as ''memory'' now. He suggested that the computer should have a unit dealing with understanding the instructions and executing them (the ''control unit'') and a unit dedicated to perform operations (today's ''arithmetic and logic unit''). He also suggested the idea that such a machine needed to be connected to peripherals for inputting programs and outputting results. This is the way modern computers are designed. |
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Revision as of 21:31, 28 September 2013
--© D. Thiebaut 08:10, 30 January 2012 (EST)
