CHFS

CHFS

Developer(s)	University of Szeged
Full name	Chip File System
Introduced	2011 with NetBSD 6.0
Structures
Directory contents	Red–black trees
Features
File system permissions	POSIX
Other
Supported operating systems	NetBSD

CHFS is a file system developed at the Department of Software Engineering, University of Szeged, Hungary.^[1] It was the first open source flash memory-specific file system written for the NetBSD operating system. Intended usage is over raw flash devices on embedded systems like ARM and MIPS, the filesystem is less suitable for use on consumer SSD^[2] (because consumer SSDs already make sure to not use the same physical blocks for writing modified data).

Structure

Similar to UBIFS, the CHFS file system utilizes a separate layer for handling Flash aging and bad blocks, called EBH (erase block handler). The file system itself is modelled after JFFS2, thus the internal structure is very similar.

ChewieFS

CHFS was originally called ChewieFS during development.^[1] The name was changed to avoid legal issues and to have a more neutral name.^[3]

See also

• List of file systems
• NetBSD
• chfs AIX command line option for modifying filesystems

References

1. Tamás Tóth (2011-11-10). "ChewieFS". tech-kern@NetBSD (Mailing list). Retrieved February 4, 2012.
2. Ádám Hóka (2011-11-10). "Re: ChewieFS". tech-kern@NetBSD (Mailing list). Retrieved 2019-03-05.
3. Ádám Hóka (2011-11-24). "Import mount_chfs for CHFS". Retrieved 2021-05-23.

External links

• Chip Flash File System at the Wayback Machine (archived 2018-03-08)
• ChewieFS - a JFFS2 like flash filesystem for NetBSD (Tamás Tóth, BSD-Day 2010)
• mount_chfs(8) – NetBSD System Manager's Manual