Sparse Formats (GNU tar 1.35)

### Storing Sparse Files

The notion of sparse file, and the ways of handling it from the point of view of GNU `tar` user have been described in detail in Archiving Sparse Files. This chapter describes the internal format GNU `tar` uses to store such files.

The support for sparse files in GNU `tar` has a long history. The earliest version featuring this support that I was able to find was 1.09, released in November, 1990. The format introduced back then is called old GNU sparse format and in spite of the fact that its design contained many flaws, it was the only format GNU `tar` supported until version 1.14 (May, 2004), which introduced initial support for sparse archives in PAX archives (see GNU `tar` and POSIX `tar`). This format was not free from design flaws, either and it was subsequently improved in versions 1.15.2 (November, 2005) and 1.15.92 (June, 2006).

In addition to GNU sparse format, GNU `tar` is able to read and extract sparse files archived by `star`.

The following subsections describe each format in detail.