Data Compression :: essays research papers fc

Data Compression just sounds complicated. Dont beafraid, compression is our good confederate for many reasons. It saves hard drivespace. It makes data files to handle. It also cuts those immense file downwardlyloadtimes from the Internet. Wouldnt it be nice if we could compress all filesdown to just a few bytes?There is a limit to how much you can compressa file. How random the file is, is the determining factor to how further it canbe compressed. If the file is completely random and no pattern can be found,then the shortest representation of the file is the file it self. The actual validation that proves this is at the end of my paper. The key to compressing afile is to find some sort of exploitable pattern. well-nigh of this paper willbe explaining those patterns that are unremarkably used.Null suppression isthe most primitive form of data compression that I could find. Basically,it says that if you have different fields that data is in (possibly a hand outsheet), and any o f them have only zeros in them, then the chopine just eliminatesthe data and goes straight from the empty data set to the next.Only one look up from null suppression is Run Length Encoding. Run length encodingsimply tells you how many of what you have in a row. It would change a setof binary data like 0011100001 into what the computer reads as (2)zeros,(3)ones, (4)zeros, 1. As you can see, it works on the same basic idea of findinga series of 0s (null suppression) and 1s in this case too and abbreviatingthem.Once the whole idea of data compression caught on, more peck startedworking on programs for it. From these people we got some new premises towork with. Substitutional encoding is a big one. It was invented jointlyby two people Abraham Lempel and Jakob Ziv. Most compression algorithms (bigword meaning roughly program) using substitutional encoding start with LZfor Lempel-Ziv. LZ-77 is a really neat compression in which the programstarts strike just copying the source file over to the new target file, but whenit recognizes a phrase of data that it has previously written, it replacesthe second set of data in the target file with directions on how to get tothe first occurrence of it and copy it in the directions place. This is morecommonly called a sliding-window compression because the focus of the programis always sliding all around the file.LZ-78 is the compression that mostpeople have in their homes.