Fragmentation

[BobH]

Hi Chris!

I agree that small chunks of free space scattered throughout the HDD would not be good. I suspect (don't know for sure how NTFS and the OS actually work) that when files are expanded or new files are written that the file handling code first tries to find space that is large enough to contain all of the data that it has to write. This assumes that the file handling knows how much data will be written, ergo how much space will be needed then tries to find an available space large enough to accommodate it and only breaks it up (frags it) if there is not enough free space to hold it. Eventually one would arrive at many, many very small chunks and greatly fragmented files. I would like to know if NTFS simply writes to the next chunk of available space or whether it first tries to keep the data contiguous. I agree that at some point - unless defragmentation occurs - the file system must create files in ever smaller contiguous spaces.

I also agree with your point that fragmentation of data is no longer the bugaboo of speed reduction that it once was. New drive technology - higher data density ergo smaller disks, faster spin rates, greater reliability - have done much to make fragmentation far less noticeable in most case. It is far easier and cheaper in most cases to use the technological improvements to overcome the issue. In fact, in most newer home use systems, the HDDs are probably so large compared with the actual data stored that very large percentages of the available space remains unused. That will, over time, change as the system ages; but we might be approaching the point where drive economics (size vs cost) will arrive at a point below actual demand for capacity. How many thumb drives of, say 4GB capacity, do you suppose are used to even 75% capacity? More likely than not the user simply uses more thumb drives rather than maximizing space usage.

Great discussion. Thanks!