Although there has been a LOT of AVL tree libraries available now, nearly all of them are meant to work in the random access memory(RAM). Some of them do provide some mechanism for dumping the whole tree into a file and loading it back to the memory in order to make data in that tree persistent. It serves well when there s just small amount of data. When the tree is somewhat bigger, the dumping/loading process could take a lengthy time and makes your mission-critical program less efficient. How about an AVL tree that can directly use the disk for data storage ? If there s something like that, we won t need to read through the whole tree in order to pick up just a little bit imformation(a node), but read only the sectors that are neccssary for locating a certain node and the sectors in which that node lies. This is my initial motivation for writing a storage-media independent AVL Tree. However, as you step forth, you would find that it not only works fine with disks but also fine with memorys, too.
This the second tutorial of the Writing Device Drivers series. There seems to be a LOT of interest in the topic, so this article will pick up where the first left off. The main focus of these articles will be to build up little by little the knowledge needed to write device drivers. In this article, we will be building on the same example source code used in part one. In this article, we will expand on that code to include Read functionality, Handle Input/Ouput Controls also known as IOCTLs, and learn a bit more about IRPs.
Parking LOT Simulation：
Parking LOT attendants often park cars bumper-to-bumper, several cars deep. This maximizes the number of cars they can fit into a parking LOT at the expense of complicating the process of retrieving someone s car when they want to leave. Consider the case of a person wanting to leave the parking LOT but their car is parked in the back of a row of cars. In this case, all the cars parked in front of this person s car must be temporarily moved to allow this person to leave.
Writing this book was hard work, but also a LOT of fun. Thanks to everyone who made it
possible, especially Jinny Verdonck, Thomas Kraft, Ricky Nkrumah, Kirk Bateman, and the
whole Apress crew. A big thanks goes also to the community that continuously extends and
improves J2ME Polish!
