index.md (1300B)
1 +++ 2 title = 'Files' 3 +++ 4 # Files 5 abstract storage 'devices' organised in (typically hierarchical) file system structure 6 7 file access: 8 9 - sequential (in order) vs. random access (e.g. second, then first, then third block) 10 11 file types: 12 13 - regular files, dirs, soft links 14 - special files (e.g. device files, metadata files) 15 16 file structure: 17 18 - OS' perspective: files as streams of bytes 19 - program's perspective: archives, executables, etc. 20 - is OS ever aware of the file structure? 21 22 file naming: 23 24 - different file systems have different limitations/conventions for filenames 25 - file extensions 26 - file name length: 27 - FAT: 8.3 characters (8 name, 3 extension. later extended to 255) 28 - EXT4: 255 characters 29 - Special chars in filenames: 30 - FAT: no "\*/:<>?\| etc. 31 - EXT4: no '\0' and '/' or special names '.' and '..' 32 - case sensitivity depends 33 34 file attributes: 35 36 - there's a whole bunch of them 37 38  39 file operations: 40 41 - create/delete 42 - open/close 43 - read/write 44 - append 45 - seek 46 - get attributes/set attributes 47 - rename 48 49 directories: 50 51 - persistent data structures organising and maintaining info about files 52 - file attrs stored in-band or out-of-band (both commonly used) 53 54  55 