NTFS FILE COMPRESSION

FILE COMPRESSION

File compression is a data compression method in which the logical size of a file is reduced to save disk space for easier and faster transmission over a network or the Internet. It enables the creation of a version of one or more files with the same data at a size substantially smaller than the original file.

•It allows the file to take up less space on a storage device, making it easier to transfer over the internet or otherwise.

•It is the art of representation of information in a compact form.

•These representations are created by identifying and using structure in the data.

FILE COMPRESSION ALGORITHM

• ENCODING ALGORITHM

   
  O Encoding Algorithm takes a message and generates a compressed representation of that message.

•        DECODING ALGORITHM
  O Decoding Algorithm reconstructs the original message or some approximation of it from the compressed representation.

TYPES OF COMPRESSION TECHNIQUES

•      Lossy Compression

OLossy compression reduces file size by removing unnecessary bits of information. It’s most common in image, video, and audio formats, where a perfect representation of the source media isn’t necessary.

OCommon format of Lossy Compression are MP3 & JPEG.

OThe more heavily you compress a file, the more noticeable drop in quality becomes.

ODrawback : Using lossy compression on a text file or a spreadsheet would result in garbled output.

•        Lossless Compression

OLossless compression is a way of reducing file size so that you can perfectly reconstruct the original file. Contrary to lossy compression, it doesn’t throw any information out. Instead, lossless compression essentially works by removing redundancy.

OCommon lossless formats include PNG for images, FLAC for audio, and ZIP.

OWhen you create a ZIP file from a program executable in Windows, it uses lossless compression. The ZIP file compression is a more efficient way to store the program, but when you unzip (decompress) it, all the original information is present.

FILE COMPRESSION USING NTFS

• Files compressed on an NTFS volume can be read and written by any Windows-based application without first being decompressed by another program. Decompression occurs automatically when the file is read. The file is compressed again when it is closed or saved.

• The NTFS file system used by Windows has a built-in compression feature known as NTFS compression. you can still access the files normally.

• NTFS allows for the compression of an entire volume, of one or more folders within a volume, or even one or more files within a folder of an NTFS volume.

• The compression algorithms in NTFS are designed to support cluster sizes of up to 4 KB. When the cluster size is greater than 4 KB on an NTFS volume, none of the NTFS compression functions are available. A single "compression unit" is 16 times the size of a cluster.

                                                                      

WHEN TO USE NTFS FILE COMPRESSION

NTFS compression is ideal for:

•Files you rarely access. (If you never access the files, the potential slow-down when accessing them is unnoticeable.)

•Files in uncompressed format. (Office documents, text files, and PDFs may see a significant reduction in file size, while MP3s and videos are already stored in a compressed format and won’t shrink much, if at all.)

•Saving space on small solid state drives. (Warning: Using compression will result in more writes to your solid state drive, potentially decreasing its life span. However, you may gain some more usable space.)

•Computers with fast CPUs and slow hard disks.

WHEN TO AVOID NTFS FILE COMPRESSION

•Windows system files and other program files. Using NTFS compression here can reduce your computer’s performance and potentially cause other errors.

•Servers where the CPU is getting heavy use. If NTFS compression used on a server with a high CPU load, the server’s CPU load will increase and it will take longer to access files.

•Files in compressed format. (You won’t see much of an improvement by compressing your music or video collections.)

•If the laptop has a very slow hard disk, it’s unclear whether compression would help or hurt performance.