Re: file I/O and block I/O

[Rene Herman <rene.herman@xxxxxxxxxxxx>]

On 14-05-08 13:42, Vijay Chauhan wrote:

> i have heard the terms file I/O and block I/O. I have very basic
> question:- What is difference between file I/O and block I/O ?? I
> mean file I/O itself a block I/O, isn't it?
>
> Can anyone explain in details, i shall be highly thankful.

In most contexts, the difference would refer to a filesystem being 
involved (file I/O) as opposed to I/O directly from the underlying 
device (block I/O).

Filesystems such as an ext2, ext3, fat and so on filesystem live on an 
underlying block device such as /dev/hda, /dev/sda, /dev/fd0 and so on.

When people are talking about file I/O they'd be referring to reading 
from or writing to say /mnt/floppy/foo.txt while for example reading 
sectors 0 to 64 (dd if=/dev/fd0 of=foo.bin count=64) would be I/O 
directly on the block decvice, with no filesystem getting involved.

Rene.

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