A file ending in .001 indicates that a large archive has been "spanned" or broken into smaller pieces for easier sharing or storage.
Programs like 7-Zip or WinZip can reconstruct the original data by right-clicking the .001 file and selecting "Extract". Possible Origins of "chsasan" chsasan.7z.001
The .001 file acts as the header; it contains the metadata required to join and open the rest of the volumes. A file ending in
Because "chsasan" is not a common technical term, it is likely a name chosen by the creator of the archive. Common reasons for such naming conventions include: chsasan.7z.001