On Thu, Oct 10, 2013 at 5:00 PM, Ulka Vaze <ulka.vaze@l2it.com> wrote:

Hi,
disk cache is same as filesystem cache. Also called buffer cache.
This is implemneted below fs layer.
It is basically a cache of disk blocks mainatined in RAM. (In pages)
called buffers.

Ok. So this won't contain "files" but rather "blocks" many of which will represent a single file?

The purpose of this cache is to improve performance as disk devices are slow.
You can access this cache from the kernel.
Block layer accesses this from the request structure and commits blocks on disk.
There are more layers in between like IOschedulers / SCSI etc.

Where does the mapping for file to disk pages/blocks exist? Is it in the inode or dentry entries or something else?

How does your device accesses files ?

The device itself runs stripped down version of a fairly recent Linux version (3.x). It has DMA capabilities to transfer content to/from the hosts memory from/to it's own.

Is it aware of files or you just copy raw data.

It can understand both.

More clarity on this can help.

Thanks for your inputs.

Regards,

-mandeep