Embedded Systems Design, 2nd Edition

270 Embedded systems design

The system revolves around its file structure and all physi-

cal resources are also accessed as files. Even commands exist as

files. The organisation is similar to that used within MS-DOS —

but the original idea came from UNIX, and not the other way

around. One important difference is that with MS-DOS, the top of

the structure is always referred to by the name of the hard disk or

storage medium. Accessing an MS-DOS root directory C:\ imme-

diately tells you that drive C holds the data. Similarly, A:\ and B:\

normally refer to floppy disks. With UNIX, such direct references

to hardware do not exist. A directory is simply present ...