Vibration = HDD can't write data= buffer fills up= HDD slow
therefore HDD bigger buffer = more space to hold data while the vibrations stop long enough for the hard drive to get back to writing data
Well, it surely depends.
- Are we 100% certain that the write cache is used by the R4? The R4 might elect to flush the cashe after every write.
- And are we 100% sure that write cashing is on in the actual harddiscs? It can be disabled.
I would guess that write cache is factory default on all drives now, but I am not certain. I would also guess that when a "bump" happens, the disc marks a physical sector error and writes to one of the spare sectors. Once the spare sectors are all used up, the disc disables write cache (at least, some do, example can be Hitachi). I think there are ways to run diagnostics to gain back the sectors, but then again, what do I know.
It is possible to turn on and off write cache for a drive. See how this is done on some Hitachi drives (page 13):
http://www.hitachigst.com/hdd/support/downloads/FTool_User_Guide_206.pdfGunnar