> > Why is an entire filesystem needed, instead of simply a block driver > > if the ramdisk driver cannot be used? > > > > >From documentation: > > "A relatively straight-forward solution is to write a simple block > driver for the non-volatile RAM, and mount over it any disk-based > filesystem such as ext2/ext3, reiserfs, etc. > > But the disk-based fs over non-volatile RAM block driver approach has > some drawbacks: > > 1. Disk-based filesystems such as ext2/ext3 were designed for optimum > performance on spinning disk media, so they implement features such > as block groups, which attempts to group inode data into a contiguous > set of data blocks to minimize disk seeking when accessing files. For > RAM there is no such concern; a file's data blocks can be scattered > throughout the media with no access speed penalty at all. So block > groups in a filesystem mounted over RAM just adds unnecessary > complexity. A better approach is to use a filesystem specifically > tailored to RAM media which does away with these disk-based features. > This increases the efficient use of space on the media, i.e. more > space is dedicated to actual file data storage and less to meta-data > needed to maintain that file data. So... what is the performance difference between ext2 and your new filesystem? -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
