Fig. 1
From: FASTAFS: file system virtualisation of random access compressed FASTA files
Overview of the FASTAFS file format specification. (top) A flowchart of the fastafs cache procedure. (bottom) The layout of the FASTAFS format consists of four blocks, starting with the file header, followed by the per-sequence data, the per-sequence header data and a metadata block. The file header has a file pointer to the per-sequence header block, where each sequence has a file pointer to its data. The file ends with a metadata block, currently supporting a CRC32 checksum. The raw FASTAFS file is subsequently compressed with zstd-seekable. The full specification is available on the website: https://github.com/yhoogstrate/fastafs/blob/master/doc/FASTAFS-FORMAT-SPECIFICATION.md