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Computer science for 2º THAT

 In this subject we are going to study some fundamental concepts of Computer science, and we do it by the importance, every greater day, than it has in our surroundings You remember effect 2000.

 Good this was that the clocks of the computers only considered the date in both last digits.

The fear was like thought that they were going to put everything as in the 1900 and not as in the 2000. A duro was made work to solve the problem, but, scare, was scare much and. Computer science every time invades but land in the society.

 Cars, telephones, electronicses, toys…


That would be of this world without 0 and 1. Because that is after all, to work with zero and some. An image, a song, a program is not but that 0 and 1. and thus they are transmitted by Internet.


To put an example, if we want to send a number, for example the 5, would be necessary to send it as 101, that he is the 5 in binary.


In binary it is counted just as in decimal, that is to say, if we used 4 bits this it would be


We can include in this section the Smartphone given of which they have operating system, system of storage and own computer science applications (APP).


We will see that Plate is in a Desktop computer Mother. She is the one in charge to support all the components of the CPU. It contains a series of slots or grooves where the hard disk is connected, card sound, graphical card, the base of the micro-controller, (that is the soul of the PC), the BIOS or the CHIPSEP (necessary controller of data so that it circulates the data between the different devices well). In the following image we have a sample of a plate

 2º RAM (Random Memory Access or Memoria of random access).  This is the memory that is in charge to keep the data from the computer when the programs are executed. When we opened a program, for example the DRAW, instead of being always reading the data in the hard disk, load in this chip so that it is executed faster. In the image we can see it as blocks of “grouped black tablets” in plates. If we want to extend it, which becomes is to add to another plate in some slot free of the plate mother.

Unlike the data that keep in the hard disk, when we disconnected the equipment, the data kept in RAM disappear

3º Hard Disco. Where we loaded the operating system and rest of programs. Usually it has great capacity and it is formed by a series of magnetic disks that are read by the reading heads. The discs are moved by a motor that is placed in center.

They are very well isolated by a housing so that not between the dust in his interior.

All the discs are made up of sectors, that are zones where the data keep. Important to emphasize the function of the starting sector, that is a part of the disc where is the information from Where is each data in the hard disk. We are going to put an example to understand it.

We suppose that a father comes to our is and comes search to you one of you. If he does not have the suitable information, it would be stairs arrives, downstairs ..... the reality is that the father comes and goes to conserjería, asks the manager where it is the class and the manager says the plant to him and exact door, that is to say, in this case the manager would be as the starting sector.

An important aspect is the speed at which the discs move. As the mall pillow reads the information that there is in discs, while these turn but fast, faster reads the information. The typical ones are of 5200 and 7200 rpm, being rpm, RPM.

4º Power supply. The components need electrical current so that they work and in addition all do not work to the same tension. The source provides to the current and necessary tension so that all the devices work. As it consumes energy enough, usually it takes a ventilator.

 5º graphical Card. She is the one in charge to provide the images to the monitor. If we used high resolution games it is necessary to have installed cards with good benefits.

6º Card of sound. Just like previous but this time is in charge to manipulate the sound information. Some computers have it integrated in the motherboard


7º Microprocessor. It is the heart of the computer because in this one device the tasks of the programs are executed (mathematical tasks). Usually they have a ventilator for “removing “the heat that produces. Although we thought that he is small, still is it more, because the micro is inside the device (seeing image) and in the external part they are the pins that enter the base.

8º BIOS. We already see that a computer is well completito of components, but when it ignites, How the PC knows that it must do. It must have something it says to him, ignites to you, it looks in such site and it acts. The BIOS is a small chip where a program keeps permanently that says to the computer at the time of the starting, that it must do, for example, reads the hard disk and you do what the operating system “says to you”.




Line-in, Line-Out and microphone, used for the connection of the loudspeakers and microphone. They belong to the sound card


 A peripheral one is a device that is connected to the computer so that it realises one certain tasks, for example to catch images (webcam), to move a cursor (the mouse), to print text and images (printing) etc. The problem is that they have a form to work that “perhaps” the operating system does not understand, that is to say, that the information that sends the peripheral one not is understood by the computer.

In order to solve the Driver settles it in the PC that is a small program so that the PC understands the tasks of the peripheral one.


The Monitor

The monitor also is another peripheral one that is in charge to show the information on a screen. Before nothing we are going to see what is a pixel 

Pixel: - > basic graphical unit of information. In order to understand it, if a painter must make a picture, the pixel would be the minimum amount of painting that can put on the linen cloth. In order to represent a color we needed a red subpixel, another green and another blue one, therefore each pixel is formed by three subpixel.

There are others we are not going to consider.


 This peripheral one is in charge to move a datum point of the screen to the displaced being. It works of the following way:

 1º Tenemos a diode LED that emits light and that by means of some mirrors affect the surface of the table (or the rug) and of the table is reflected to the CMOS, that is the camera of the mouse. Before arriving at the image, some lenses are in charge to concentrate all the liz so that the image arrives but it needs. The digital image is sent to the DSP.

 2º DSP (Digital Signal Processor) is in charge to process the digital image to decide if from a photogram to another one some variation has existed.

 3º Movemos the mouse and the image that arrives at the CMOS changes. The digital information arrives at the DSP and this one calculates since it has moved, that is to say, compares the previous image and the later one and decides that displacement has existed. After some very precise calculations send the variation to the cursor of the screen.


  1. Another peripheral one whose function is to print the document on paper that we have in the Computer, although already the majority includes the scanner and the photocopier including. There are three fundamental types
  2. Red injection with injector in cartridge
  3. Red injection with separated injector of the cartridge

Printers laser

Two first the functional one with carcuchos of red (3 for color and one black and white one) with the difference of which the system that injects the red in the paper is in favor in the same cartridge (are but expensive) but of some reason is dried, changing the cartridge is solved the problem, something that does not happen with those of type 2

The printers laser do not have that problem, are but trustworthy, fast and its price is lowering significantly.

 Scanner. With this device we can make copies of other original ones. The system is the following one:

 a) By means of a light source, the image of the original one is bounced and guided by means of some mirrors until the CCD



b) The CCD takes the image and it turns it to a digital format, that is to say, “passes each ray of light, with his color and its luminosity to zero and some”


c) Once digitized the image one goes to the computer to be processed and to create the digital image.

In the image of the left is a device CCD, in charge to pass the images to 0 and 1. According to the resolution of the scanner, the digital image will be but exact to the original one



It realises the activities that you will find in:

Activities of Computer science for 2º THAT

Design PCB