anatomy of device drivers

now that wen i have got a good response for this post on device drivers i wud love to thankyou all and share more..now let us examine the anatomy of the device driver..
i mean the major components of a driver..from my previous post we can percept that device driver is a software with a set of entry
points that can be called by the operating system.it can also contain *data structures private to the driver*references to kernel data structures external to the driver*routines private to the driver..here i dont mean entry points..instead routines..
now let me stop boring you ppl with the theory part and jump into programming.. :) :)
most drivers are written as a single source file or set a set of dependent files and
compiled usign make command..(before that we gotta write the Makefile specifying the order
of compilation of all the .o files)
the initial part of the driver source file is called as a prologue and the rest contains entry points.
the prologue contains the initialization part as most of the .c files are written.
* #include-header files * #define-all the constants used in the driver * all the variable declarations and data structures
as said before the remaining part contains the entry points

like init,exit,open,read,write,close and all
k let me continue in my next post..got some work :(