Dan99 - 4:03 pm on Oct 17, 2013 (gmt 0)
OK, just to get some closure here. The reason for all those 206 requests, for tiny chunks of a file at a time, is now resolved. Curiously, this only seemed to happen for pdf files.
That's what happens when pdf-display enabled browsers use the "fast web view" option on pdf files. That option allows the browser to download a page at a time, so one can start looking at the document before it is completely downloaded. It's handy for the person viewing the document, but it sure fills the Apache log on the server with pages of crap if the documents are lengthy.
How to keep from getting loads of 206 requests in your Apache log? Simple. Just don't post pdfs for download with "fast web view" enabled.