KDPeter?

Can you believe that the code above can be optimized to run 14 times faster on Intel Core i7 CPU and to run 40 times faster on AMD Athlon X2? #define X_SIZE 60 #define Y_SIZE 30 int matrix[X_SIZE][Y_SIZE]; void initmatrix(void) { int x,y; for (x = 0; x < X_SIZE; ++x){ for (y = 0; y < Y_SIZE; ++y){ matrix[x][y] = -1; } } } void main() { initmatrix(); } Check my post:   C code optimization benchmark

The article: Writing device drivers in Linux: A brief tutorial Is a great starting point for Linux Kernel Development but it needs some simple updates. The first error you will find when compiling is: /home/peter/devel/kdpeter/2012/bricks/original-post/memory.c:3:26: fatal error: linux/config.h: No such file or directory compilation terminated. To fix, remove the line from the source code: #include <linux/config.h> Then some warnings: /home/peter/devel/kdpeter/2012/bricks/original-post/memory.c:28:3: warning: initialization from incompatible pointer type [enabled by default] /home/peter/devel/kdpeter/2012/bricks/original-post/memory.c:28:3: warning: (near initialization for ‘memory_fops.write’) [enabled by default] /home/peter/devel/kdpeter/2012/bricks/original-post/memory.c: In function ‘memory_write’: /home/peter/devel/kdpeter/2012/bricks/original-post/memory.c:110:17: warning: ignoring return value of ‘copy_from_user’, declared with attribute warn_unused...

Can you believe that a two line C source code can become a Linux module? $ cat simplest_module.c #include <linux/module.h> MODULE_LICENSE("GPL"); $ cat Makefile obj-m := simplest_module.o all: make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules clean: make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean Just "make". $ make To install your brand new bogus module: $ sudo insmod simplest_module.ko The lsmod command show that your module has been loaded: $ lsmod |grep simplest_module simplest_module          689  0 To remove the module: $ sudo rmmod simplest_module It is very simple to create a Linux Kernel Module. If you want more than a do nothing module, follow the links: Source:  Writing device drivers in Linux: A brief tutorial Recommended:  Writing a Simple USB Driver