Need help for getting hard-disk traces

[nagraz007]

When we write a programme,we declare variables and compiler allocates memory to them.I want to get access to the physical block number of hard-disk where actually the data is stored by the programme "

Some one help me out


Hope my question is clear

[Rubberman]

In-memory variables are not stored on the disc unless it is swapped out due to memory constraints.

[nagraz007]

if its allocated on hard -disk due to memory constraints....how will i be able to get exact places on hard-disk where it places them...I need to get the trace of them.....so that i can get a pattern where/how data is stored on hard-disk ...
hoping for reply

[Rubberman]

When data is swapped to HDD due to memory constraints, it all goes to the swap partition(s) and/or file(s). There can be any number of those, so where it goes on disc is indeterminate - depends upon which sectors are available to place the data. Where regular data that is deliberately written to disc goes when a program writes it again depends upon where space is available, and specific storage algorithms used by the file system in question - each behaves very differently. So, I have to ask you, why do you want/need to do this? Is it a school project?

[nagraz007]

yes..its part of my project...my mentor asked to find out a way to get actual physical block numbers in hard-disk where data gets stored on hard-disk....so to get the pattern in which it places the data on the disk and hence to get an idea about multi-zonal recording on disks ...

can u help me wid where and which part of linux code does this ....

[Rubberman]

Sorry, but the terms of use for the forums precludes helping with school work. As I said, each file system type ( ext2/ext3, ufs, jfs, xfs, zfs, fat, ntfs, etc. ) will exhibit very different patterns of storage, a lot of which depends upon the level of fragmentation found in the file system. You need to study the file system drivers for each type you are interested in to determine how to find where on the disc (absolute physical sector # on the partition) the data is stored. That's as far as I can help you.