On Wednesday 01 September 2004 22:30, der Mouse wrote:
> Well, devices _are_ often special in various ways. Most notably
> here, disk devices normally do not support accesses that are not a
> multiple of the sector size, aligned on sector boundaries. (Since
> most emulators don't try to do anything else with disks, they
> probably will work fine. This is partly just general misimpression
> correcting, but also partly because you may run into trouble if you
> try to use something like a CD - the CD blocksize is fundamentally
> 2352, which turns into 2K for a data CD (the other 304 bytes going
> for ECC and suchlike), and many CD drives don't support sub-2K
> accesses, meaning you may not be able to use a CD to back even a
> read-only disk.)
A proper OS device driver will figure out that you're not
reading/writing a whole block (or on a block boundary), and give you
back or modify only what's required, when using a read()/write()
syscall or fread()/fwrite(). :)
Pat
--
Purdue University ITAP/RCS --- http://www.itap.purdue.edu/rcs/
The Computer Refuge --- http://computer-refuge.org
Received on Thu Sep 02 2004 - 00:12:58 BST