file-system

来自「COS 0.0.1.rar Cos操作系统源代码」· 代码 · 共 33 行

My idea for the first COS file system is just to write something really
simple which can be used for testing.

<START OF DISK>
Superblock - Specifies disk/partition size, virtual block size
			and pointer to root directory.
	
Block table - Simple bitmap showing which blocks are free/used/bad.

At other locations we will have

Directory block - stores file names, types, sizes and other meta data.
			In later versions of the file system most of this
			data will be moved to inodes or the like.
			Also stores a pointer to a 'file' block for each file.

'File' block - This will just store the addresses of the blocks used
			to store the file data.

Data block - Self-explanatory.

Notes:
We use a virtual block size so files can be allocated blocks of a
different size to the size of disk blocks. All low-level reading and
writing will still be done in disk blocks but a layer on top of the disk
driver will hide this from the file-system driver which will be able to
specify its own block size.

The file type will be stored separately from the file name as a 32-bit
integer. In later versions a table of file types will also be stored.

No support for device nodes or other weird stuff, nor permissions or
users YET. Expect these soon after the initial file system has been tested.