How much space does a Write Filemarks command use?
It could use 0 to 8KBytes. A Write Filemarks command appends the requested number of Filemarks to any data in the cache and writes the combination to the media. If the last physical block (always 8KB) is only partially full it must still be written to media. This normally results in an insignificant capacity loss. In some applications a Write Filemarks, 0 command is used to force any data in the cache onto the media (a cache flush). A Write Filemarks, 0 command does not result in a logical block of itself — only the data written to the cache by previous commands, will make up the block. If Write Filemark, 0 commands are issued very frequently, they could affect both the capacity and throughput of the drive. A Write Filemarks, 1 command will cause 1 filemark to be appended to the current block and written to media The filemark will takes up from zero to 8K bytes, depending on the unused space left in the 8K physical block when the command was issued. After a first filemark is written,
