My Tech notes

STEPS FOR CROSS COMPILING X11 FOR ARM Go to /usr/X11R6/lib in my linux PC. 1) install ARM toolchain, If not installed 2) Get x11 source from http://www.x.org/ 3) extract all the tar files, using tar -xvzf 4) edit cross.def and host.def files, in cross.def set the paths of tool chain in host.def file set crossCompile to YES and DoLoadableServer to NO 5) make shadow directory "build" and link to xc "lndir ../xc" 6) run Make World error: linux_vm86.c 281 impossible constraint in 'asm' 268 res might be used uninitialized in this function. fix:comment line 281, set res=0 error: implicit decleration of function 'SET_FLAG' fix: comment line 111 in programs/Xserver/hw/xfree86/os-support/linux/int10/helper_exec.c error:Undefined reference to XF86VidModeQueryVersion in glxinfo And glxgears Undefined reference to XF86VidModeQueryVersion in xdriinfo fix:download libXxf86vm.so.1.0 into our armtoolchain lib path and make softlinks ln -s libXxf86vm.so.1.0 li...

The Advancement of technology had entered into nanometer age. search in google define:Blue-ray will get wiki pages here is summary of it. Blu-ray Disc (also known as Blu-ray or BD) is an optical disc storage medium designed to supersede the standard DVD format. Its main uses are for storing PlayStation 3 games, high-definition video, and data storage, with up to 50 GB per disc. This is quite impressive, The disc has the same physical dimensions as standard DVDs and CDs. Why Blu-ray disc stores 50GB on same size of DVD/CD? Well here is advancement of laser technology, thanks to Shuji Nakamura for his invention on blue laser, The name Blu-ray Disc derives from the blue-violet laser used to read the disc. While a standard DVD uses a 650 nanometre red laser, Blu-ray uses a shorter wavelength, a 405 nm blue-violet laser, and allows for almost six times more data storage than on a DVD. check out about Blu-ray Movies - Everything about Blu-ray movies and releases .at http://www.blu-ra...

Get HyperSCSI for SAN - Storage Area Network SCSI (Small Computer Systems Interface) family of protocols. HyperSCSI can allow one to connect to and use SCSI and SCSI-based devices (like IDE, USB, Fibre Channel) over a network as if it was directly attached locally. Why HyperSCSI over iSCSI? The main advantage of HSCSI compared to iSCSI is especially a lower network load as well as an end system (server and client) load. TCP/IP SAN performance is still not good enough without hardware acceleration FC-based SANs cannot do Storage Wide-Area Networks Fully functional software implementation of both client and server so HSCSI can be used for a solution built on commonly available hardware, no expensive and specialized hardware is needed. Therefore, HSCSI can be used for building small and cheap SANs. HSCSI main disadvantage is this protocol has no official standard like iSCSI nd so it is unsupported in any way by manufacturers developing hardware data storage solutions. Two modes of oper...

As a kernel or device driver developer one must know what Linux kernel can not 1) No access to C library Generally, C library is large. Accessing a C lib function from kernel space is very time consuming. It affects the kernel speed and size. So many libc functions are implemented in the kernel. Just like printf in libc is implemented as printk in kernel. 2) The kernel lacks memory protection. Application in user space lacks memory protection. so when an application access illegal memory location, it results in segment violation. But when in kernel space segment violation occures, it results in oops. It is a major kernel error. 3) Difficult to use floating point. When floating point arithmetic is done in user space, kernel manages the transition from integer to floating point mode. But enabling floating point in kernel, the kernel requires manually saving and restoring the floating point register. It is extra overhead for kernel. 4) Limited and small stack Linux kernel has very small ...

Google Chrome OS is an open source, lightweight operating system. It is designed mainly considering netbooks. The notebooks will be available to consumers in mid 2010. This will be an open challenge to its rival MS Window. The key aspects of Google Chrome OS are its security, simplicity and speed.

Monolithic kernel has simple design. Monolithic kernel is a single large processes running entirely in a single address space. It is a single static binariy file. All kernel services exist and execute in kernel address space. The kernel can invoke functions directly. The examples of monolithic kernel based OSs are Linux, Unix. In Microkernels, the kernel is broken down into separate processes, known as servers. Some of the servers run in kernel space and some run in user-space. All servers are kept separate and run in different address spaces.The communication in microkernels is done via message passing. The servers communicate through IPC (Interprocess Communication). Servers invoke "services" from each other by sending messages. The separation has advantage that if one server fails other server can still work efficiently. The example of microkernel based OS are Mac OS X and Windows NT.