Messages in this thread | | | Date | Tue, 01 Apr 2008 11:45:56 +0300 | From | Artem Bityutskiy <> | Subject | Re: UBIFS vs Logfs (was [RFC PATCH] UBIFS - new flash file system) |
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Tomasz Chmielewski wrote: > For me, the motivators to wait for LogFS are mainly the facts that it > can work on traditional block devices, and not only on pure flash:
Sorry Thomasz, for me this makes zero sense. There are _much_ better file systems for block devices. UBIFS may work on top of a block device as well (just needs few hacks to make it possible) - it is not a problem at all, it is just _senseless_.
JFFS2/UBIFS/LogFS is a separate _class_ of file-systems. The are designed for _flash_, which has completely different work model then block device. They are _native_ flash file systems. Here are more details: http://www.linux-mtd.infradead.org/faq/general.html#L_mtd_vs_hdd
The traditional FSes _cannot_ work on top of flash. The solution for this is using FTL, which emulates a block device on top of flash. It _hides_ the real device, and fakes a block device for you. And you can use traditional FSes on top of that fake block device.
The whole _point_ of this separate class of FSes is because we believe we may do much _better_ job if we use flash _natively_, instead of using FTL. FTL is the place where you loose performance, reliability, and so on.
And you are saying about using a native flash FS on top of a block device like an SD card. This is just not sane: SD card first emulates a block device for you, looses performance at this point, then you again emulate a flash on top of this, and suffer from this again.
-- Best Regards, Artem Bityutskiy (Артём Битюцкий) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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