翻译grub2的过程中遇到了这个词，ext4的文档中有这么一段：
...... 2.4. Extents The traditionally Unix-derived filesystems like Ext3 use a indirect block mapping scheme to keep track of each block used for the blocks corresponding to the data of a file. This is inefficient for large files, specially on large file delete and truncate operations, because the mapping keeps a entry for every single block, and big files have many blocks -> huge mappings, slow to handle. Modern filesystems use a different approach called "extents". *An extent is basically a bunch of contiguous physical blocks*. It basically says "The data is in the next n blocks". For example, a 100 MB file can be allocated into a single extent of that size, instead of needing to create the indirect mapping for 25600 blocks (4 KB per block). Huge files are split in several extents. Extents improve the performance and also help to reduce the fragmentation, since an extent encourages continuous layouts on the disk. ...... Wiki上也有类似的解释 http://en.wikipedia.org/wiki/Extent_%28file_systems%29 那么这个extent应该怎么翻译成中文呢？ 连续块？ 扩展块？ 块扩展？ 请大家给点意见。 -- Best Regards, Alex
