computer learningorg

 

Data recovery

 

                                                   finding an answer to data recovery and make huge back up we need to understand how the data is stored in a hard disk commonly HD is a data soring device known as secondary storage that can store data as in the form of 0's and 1's HDDs record data by magnetizing ferromagnetic material directionally, to represent either a 0 or a 1 binary digit. They read the data back by detecting the magnetization of the material. A typical HDD design consists of a spindle that holds one or more flat circular disks called platters, onto which the data are recorded. The platters are made from a non-magnetic material, usually aluminum alloy or glass, and are coated with a thin layer of magnetic material, typically 10–20 nm in thickness — for reference, standard copy paper may be between 0.07 millimetres (70,000 nm) and 0.18 millimetres (180,000 nm) thick.^[8] — with an outer layer of carbon for protection. Older disks used iron(III) oxide as the magnetic material, but current disks use a cobalt-based alloy

 

 

              How the data recovery works? A common misconception is that the data is actually removed from the hard drive (erased) when you delete a file. Any time that a file is deleted on a hard drive, it is not erased. Instead, the tiny bit of information that points to the location of the file on the hard drive is erased. This pointer, along with other pointers for every folder and file on the hard drive, is saved in a section near the beginning of the hard drive and is used by the operating system to compile the directory tree structure. By erasing the pointer file, the actual file becomes invisible to the operating system. Eventually, the hard drive will write new data over the area where the old file is located.

                                                                                                                     There are several hard disk utilities that you can find on the Internet that allow you to recover "deleted" files. What these utilities do is search for data on the hard drive that does not have corresponding pointer information and present you with a list of these files. Your chances of fully recovering a file diminish the longer you wait after you deleted the file since the probability that the file has been overwritten increases. Sometimes you can recover portions of a file that has not been completely overwritten.

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Making a Computer solution

                                                          

What is a computer solution? A solution is a word that is used to refer to solving and maintaining a user friendly system. It is a group of machines organised by programs. Take supermarkets for example. In day to day life all or us are familiar with supermarkets, all of us go there and buy goods. We alwayssee lots of machines and these are all part of retail solutions.,

                                                                                        bar code reader

 

 

 

 

 

 

 

 

 

                                                                              printers

 

 

 

 

 

 

as well as security installations, such a cameras. These all co-ordinate data for supermarkets. If we dig into these solutions a little more we can find the answers to questions listed below.

                                      What stock is available?

                                      What product is more attractive to customers?

                                      What is the criteria for buying stock for the supermarkets?

                                      What is the quality of each product?

                                      How can a customer find a product easily in the store?

                                      How does one keep the customer happy?

                                      How can the supermarket prevent shop lifting from their store?

                                      Establishing criteria for buying products for the supermarket.

 

 

 Analysing these strategies, we can find some solutions, For the first example, what stock is available? If we need to find this out, a well organised computer system, with each tally point connectd to server, then the server can establish  what has been sold more of and what needs to be purchased. The bar code reader is used to price each product. A customer service provider can tell the customer   where the product is.

 From this picture we can find server need a software that can make Back up in at every shut down  And only made to make admin can fetch data from it Then the client machine's need application That only used for billing Collecting data's from Peripherals connected to it and tell to server What is sold out there

 

Decision making - a methodology

             What all are the ways to arrange randomly selected cards?. now we can add an algorithm here by step by step

                                                                                                                                                                   

                                                     algorithm for sorting randomly selected cards

 

                                                                        STEP1:start

                                                                      

                                                                        STEP2:take the card

 

                                                                        STEP3:Check it is sorted or not

 

                                                                        STEP4:if sorted go to 5 else go to 2

 

                                                                        STEP5:end

 

 

 Here is the basic  algorithm for sorting cards, Then go to find a solution for sorting cards

 

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