Linux - NewbieThis Linux forum is for members that are new to Linux.
Just starting out and have a question?
If it is not in the man pages or the how-to's this is the place!
Welcome to LinuxQuestions.org, a friendly and active Linux Community.
You are currently viewing LQ as a guest. By joining our community you will have the ability to post topics, receive our newsletter, use the advanced search, subscribe to threads and access many other special features. Registration is quick, simple and absolutely free. Join our community today!
Note that registered members see fewer ads, and ContentLink is completely disabled once you log in.
If you have any problems with the registration process or your account login, please contact us. If you need to reset your password, click here.
Having a problem logging in? Please visit this page to clear all LQ-related cookies.
Introduction to Linux - A Hands on Guide
This guide was created as an overview of the Linux Operating System, geared toward new users as an exploration tour and getting started guide, with exercises at the end of each chapter.
For more advanced trainees it can be a desktop reference, and a collection of the base knowledge needed to proceed with system and network administration. This book contains many real life examples derived from the author's experience as a Linux system and network administrator, trainer and consultant. They hope these examples will help you to get a better understanding of the Linux system and that you feel encouraged to try out things on your own.
Click Here to receive this Complete Guide absolutely free.
I compiled the program using gcc 3.2.3 as follows
gcc -o test test.c
Ran the program as follows :-
The output was as follows :-
fd = 3
errno = 22
file read failure:: Invalid argument
Anybody has any ideas why the program fails to read the raw device. The program can read other files successfully. It only has problems reading raw devices. Could not find anything on the net. The Oracle server seems to be able to read the raw device but my program cannot. Any help would be appreciated.
I think I know what is happening. Since you are using direct I/O the buffers you pass to
the read and write call *have* to be *boundary alligned*
If you just reserve an array, no one guarantees that the memory area for that array
is memory alligned.
So I have changed a little bit your program, in the way that now
memalign is used instead of an array. I have used 512 Byte as boundary
which is the default disk sector size. The reserved size is 1k (1024 Byte)