For those of you who have been around long enough to experience some of the earlier PDAs based on flash memory like Palm's initial Pilot and later, devices like the iPaq that were based on Microsoft's PocketPC operating system, then you'll remember what a drag it sometimes was when those devices became so inoperable that you had to issue what is known as a hard reset to return them to a functioning state. Like other personal devices that have come before it, Amazon's Kindle ebook client …