Index: en_US.ISO8859-1/books/arch-handbook/driverbasics/chapter.xml =================================================================== --- en_US.ISO8859-1/books/arch-handbook/driverbasics/chapter.xml +++ en_US.ISO8859-1/books/arch-handbook/driverbasics/chapter.xml @@ -385,12 +385,15 @@ block-devices almost unusable, or at least dangerously unreliable. The caching will reorder the sequence of write operations, depriving the application of the ability to know the - exact disk contents at any one instant in time. This makes - predictable and reliable crash recovery of on-disk data + exact disk contents at any one instant in time. + + This makes predictable and reliable crash recovery of on-disk data structures (filesystems, databases etc.) impossible. Since writes may be delayed, there is no way the kernel can report to the application which particular write operation encountered a write error, this further compounds the consistency problem. + + For this reason, no serious applications rely on block devices, and in fact, almost all applications which access disks directly take great pains to specify that character (or