TICO 2

To know what is defragmentation, first we have to talk about fragmentation. 

Fragmentation consists in the division of a file when there are spaces divided and the file does not enter completely in one of them. The solution is the freagmentation of the file in the different spaces along the hard drive. For example, imagine you have a hard drive with 10 spaces and you have 3 files: the first occupies 2 spaces, the second occupies 2 and the third occupies 4 spaces. You then delete the second one and a space is left there. Finally you want to download a file that occupies 4 then the file needs to be divided into 2 parts of 2 spaces each. That file has been fragmented.

The defragmentation is the process where the files in a hard drive are organized so the fragmentation does not need to take place. If this process is automatically done by the O.S, it is called auto defrag. So in the example before, when the second file is removed, the O.S would have automatically moved the third file to the left space if it has auto defrag.

Windows has the option of turning the auto defrag on and off in the data disk properties.

The Von Neumann model consists on the explanation of how a computer works. It says that the computer is divided into three sections: CPU, RAM and INPUT/OUTPUT.

The CPU is the brain of the computer. It sends orders to the RAM and to the INPUT/OUTPUT sections. It also process data.

The RAM is a table where its registrated where the data is saved. Before a program is runned, it is registered and download in the RAM so the next time you open it, it  will be faster.

The INPUT/OUTPUT consists in all the devices connected to the computer. They can be internal or external. The Hard drive is inside this group

This three parts are connected by BUSES that consist on cables. There are three types of BUSES: data, adress and control. The data bus transmit all the things in the file. The adress bus transmit information about where the file is located. The control bus transmit the order.

For example if you want to open a file in the hard drive, the RAM transmits through the adress bus where the file is located to the CPU. Then, the CPU transmits the order of open it through the control bus to the INPUT/OUTPUT section. Finally, the file is passed through the data bus to the CPU and to the RAM and then it is shown on screen. 

The CPU is the central processing unit, and it basically gives commands, performs basic artihmetic, logic, controlling, and operations speficied by the instructions in the program. It is generally composed of the main memory, control unit and arithmetic-logic unit. Some computers employ a multi-core processor, meaning it has 2 or more.

The RAM is the random acess memory. It is a super-fast storage that the computer uses to hold data that will be needed in the short term, as when you open a program. It is typically used to store working data and machne code, and this basically allows data items to be read or written in almost the same amount of time irrespective of the physical location of data inside the memory. 

The HD is the hard drive, it is the component that stores all of the difital content that stores the instructions that the CPU needs to work, as well as documens, pictures, music, videos, programs and application preferences. Your can think of you HD as a diling cabinet where all your data is stored and te RAM like your desk, where you put the stuff you are currently working on. Hard drives can be external or internal, in the slides shown you can see an example of each.

The Cache is a storage space for temporary files that makes a device, browser, or app run faster and more efficiently. After opening an app or website for the first time, a cache stashes files, images and other relevant data on your device. A cache's primary purpose is to increase data retrieval performance by reducing the need to acess the underlying slower storage layer. Trading off capacity for speed, a cache typically stores a subset of data transiently, in contrast to databases whose data is usually complete and durable.