Sam Format
From Biowiki
SAM and BAM format
SAM (Sequence Alignment/Map) plaintext format and the associated binary BAM format are used to represent alignments of next-generation sequencing reads to reference genomes.
The format is documented at the SamTools website: http://samtools.sourceforge.net/
The plaintext SAM format incorporates elements of other bioinformatics file formats, including Cigar format and FASTQ format.
-- Ian Holmes - 20 Mar 2011