hi im gonna have to agree with fisha this link basically repeats what fisha said: http://www.absoluteastronomy.com/encyclope...a/hard_disk.htm (search for alittude) plus if u do a google search it says that apple ipods have a 10,000 ft limit. so unless sony uses some special hardrives (which i doubt anyone would do on a consumer product)....use at ur own risk. also, my friend who does private flying tells me that he cannot use his laptop above 10,000 ft becomes of the hardrive issue. btw, some hard-drives are designed to operate at higher altitudes / lower pressures through modifications in design, however that also means that they cannot be used at sea level due to the same issue (the heads will now be too far above the platter b/c the pressure is too high) if you can find out what type of hard drive the daps use, then u can always email the manufacturer directly zack