ZIP File Strukture

Zip is a file format used for data compression and archiving. A zip file contains one or more files that have been compressed, to reduce file size, or stored as is. The zip file format permits a number of compression algorithms.

The format was originally created in 1989 by Phil Katz, and was first implemented in PKWARE's PKZIP utility,as a replacement for the previous ARC compression format by Thom Henderson.

The zip format is now supported by many software utilities other than PKZIP. Microsoft has included built-in zip support (under the name "compressed folders") in versions of Microsoft Windows since 1998. Apple has included built-in zip support in Mac OS X 10.3 (via BOMArchiveHelper, now Archive Utility) and later, along with other compression formats.

Zip files generally use the file extensions ".zip" or ".ZIP" and the MIME media type application/zip.Zip is used as a base file format by many programs, usually under a different name.

Zip files are often represented by a document or other object prominently featuring a zipper.

Magic Number

Magic numbers are common in programs across many operating systems. Magic numbers implement strongly typed data and are a form of in-band signaling to the controlling program that reads the data type(s) at program run-time. Many files have such constants that identify the contained data. Detecting such constants in files is a simple and effective way of distinguishing between many file formats and can yield further run-time information.

Unallocated Space

Unallocated Space is available disk space that is not allocated to any volume. The type of volume that you can create on unallocated space depends on the disk type. On basic disks, you can use unallocated space to create primary or extended partitions. On dynamic disks, you can use unallocated space to create dynamic volumes.

Unallocated space is simply defined as the area or space on the hard drive of the computer that is available to write data to.