Where should the type information be 132

Trevor L. Jackson, III

deletes that reliance

If every file requires at least one datum block, there is an upper bound on the size of the directory (i-node space, in Unix terms), and this can be exploited in several ways. For example, block allocation can favour certain areas on disk for allocating directory blocks, without pre-allocating. It also permits operating well when the file system is over 99% full, including reliable recovery when running out of blocks ("allocation good to the last block").

Empty files arise when file creating is separate from file writing. In the filesystem I use there is no separate file creation (a file is created by the first write to a non-existent fileid), so the issue doesn't arise. File truncation specifies the offset of the last surviving item, so again it is simply not possible to create an empty file (it is not forbidden -- it simply can't happen).

implementation

That is indeed how the illusion of empty files can be created. Items (lines) are numbered from 0, but by convention the first line of user data is line 1; line 0 is used for annotation. Pure byte spaces ("F1" format) would however naturally be used starting with offset 0, so the issue would arise. Michel.