The Be File System (BFS) is the native file system for the BeOS. In the Linux kernel, it is referred to as "BeFS" to avoid confusion with Boot File System.
| Developer(s) | Be Inc. |
|---|---|
| Full name | Be File System |
| Introduced | May 10, 1997 with BeOS Advanced Access Preview Release[1] |
| Partition IDs | Be_BFS (Apple) 0xEB (MBR) 42465331-3BA3-10F1-802A-4861696B7521 (GPT) |
| Structures | |
| Directory contents | B+ tree[2] |
| File allocation | inodes |
| Bad blocks | inodes |
| Limits | |
| Max volume size | ~2 EB * |
| Max file size | ~260 GB * |
| Max no. of files | Unlimited |
| Max filename length | 255 characters |
| Allowed filename characters | All UTF-8 but "/" |
| Features | |
| Dates recorded | Access, Creation, Modified |
| Date range | Unknown |
| Date resolution | 1s |
| Forks | Yes |
| File system permissions | Unix permissions, POSIX ACLs |
| Transparent compression | No |
| Transparent encryption | No |
| Other | |
| Supported operating systems | BeOS, ZETA, Haiku, SkyOS, Syllable, Linux |
BFS was developed by Dominic Giampaolo and Cyril Meurillon over a ten-month period, starting in September 1996,[2] to provide BeOS with a modern 64-bit-capable journaling file system.[3] It is case-sensitive and capable of being used on floppy disks, hard disks and read-only media such as CD-ROMs. However, its use on small removable media is not advised, as the file-system headers consume from 600 KB to 2 MB, rendering floppy disks virtually useless.
Like its predecessor, OFS (Old Be File System, written by Benoit Schillings - formerly BFS),[4] it includes support for extended file attributes (metadata), with indexing and querying characteristics to provide functionality similar to that of a relational database.
Whilst intended as a 64-bit-capable file system, the size of some on-disk structures mean that the practical size limit is approximately 2 exabytes. Similarly the extent-based file allocation reduces the maximum practical file size to approximately 260 gigabytes at best and as little as a few blocks in a pathological worst case, depending on the degree of fragmentation.[citation needed]
Its design process, application programming interface, and internal workings are, for the most part, documented in the book Practical File System Design with the Be File System.[2]
Implementations
editIn addition to the original 1996 BFS used in BeOS, there are several implementations for Linux. In early 1999, Makoto Kato developed a Be File System driver for Linux; however, the driver never reached a completely stable state, so in 2001 Will Dyson developed his own version of the Linux BFS driver.[5]
In 2002, Axel Dörfler and a few other developers created and released a reimplemented BFS called OpenBFS for Haiku (OpenBeOS back then).[6] In January 2004, Robert Szeleney announced that he had developed a fork of this OpenBFS file system for use in his SkyOS operating system.[7] The regular OpenBFS implementation was also ported to Syllable, with which it has been included since version 0.6.5.
See also
editReferences
edit- ^ Scot Hacker (1997-07-01). "BeOS Journal 10: A First Look at DR9". ZDNet. Archived from the original on 1999-10-02. Retrieved 2007-03-22.
- ^ a b c Giampaolo, Dominic (1999). Practical File System Design with the Be File System (PDF). Morgan Kaufmann. ISBN 1-55860-497-9. Archived from the original (PDF) on 2017-02-13. Retrieved 2004-06-01.
- ^ Andrew Orlowski (2002-03-29). "Windows on a database – sliced and diced by BeOS vets". The Register. Archived from the original on 30 December 2006. Retrieved 2006-12-09.
- ^ Henry Bortman. "Benoît Schillings, Software Engineer". The BeOS Bible. Archived from the original on 27 September 2006. Retrieved 2006-09-10.
- ^ Will Dyson (2002). "BeFS driver for Linux: About BeFS". SourceForge. Retrieved 2006-12-09.
- ^ Daniel Teixeira (2002-09-04). "OBFS Reaches Beta". Haiku News. Archived from the original on 2006-10-04. Retrieved 2006-12-09.
- ^ Robert Szeleney (2004-01-23). "Update". skyos.org. Archived from the original on 2007-09-26. Retrieved 2006-12-09.
External links
edit- The BeOS file system: an OS geek retrospective, by Andrew Hudson, 2010-06-03, Ars Technica