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Journaling Flash File System

Posted by timothy on from the dear-diary-100100100110010 dept.

menthos writes: "It seems like Axis Communications has brought a YAJFS (Yet Another Journaling File System) to Linux. It is however a bit different, in that it is designed for flash memory filesystems, as in Axis's own Web cams. It is GPL, and the JFFS link is here. Maybe this could mean more Linux PDAs?"

1 of 28 comments (clear)

  1. Why a flash jfs? by Olivier+Galibert · · Score: 5

    Because flash memory is not standard memory. In particular it has slower access times and does not like to be written to often that much. This makes using caches necessary for good performance (especially on 200+ Mhz handhelds).

    But if you use caches, there's always the question of what happens in the case of a power outage (as in, the battery just popped off). Journaling allows to go back quickly to a reasonable state 99.9% of the time (at least). To the point that the user will probably not notice the problem.

    Incidentally, a jfs does _not_ protect against disk crashes at all, it is not designed for that. If you want protection against (most) disk crashes, what you need is RAID.

    Actually, if you want very reasonable data security without daily backups, especially given the current cost of large disks and comparable-size backup systems, you probably need a jfs+raid combination.

    OG.