User Mode Vs Kernel Mode

All programs or processes when running are executed in User mode. Processes do not interact directly with the kernel but they just give instructions in form of system calls and the kernel mode will take care of the rest.

Switching to kernel mode requires one of these to happen, an interrupt, a trap and  I/O or event occurrence.
The kernel mode responds to the request for example handling of device drivers, memory allocation and others which we refer to as privileged instructions, and the process is switched back to user mode where we find less privileged instructions.


"When the computer boots up, Windows calls the KERNEL, the

main kernel-mode program that allows all the other programs
to run, even the user-mode programs".

http://www.allinterview.com/showanswers/67083.html

Operating System Programming

It has always been a challenge to know how the OS was built. The release of the Win 32 bit OS was a basis for the development of win 64 bit OS. The C-language is a basis for many operating systems. You can also program your OS or even learn how Windows was built. for more info visit "http://www.tenouk.com/cnwin32tutorials.html"

UNIX Operating System

Many people have a lot of questions concerning what UNIX is, most OS's falling in this category were developed using the C-language.



"Since PDP-11 Unix became operational in February, 1971, over 600 installations have been put into service. Most of them are engaged in applications such as computer science education, the preparation and formatting of documents and other textual material, the collection and processing of trouble data from various switching machines within the Bell System, and recording and checking telephone service orders. Our own installation is used mainly for research in operating systems, languages, computer networks, and other topics in computer science, and also for document preparation."


More Information on http://www.livinginternet.com/i/iw_unix.htm

And the name UNIX, In 1970 Peter Neumann coined the project name Unics (UNiplexed Information and Computing Service) as a pun on Multics, (Multiplexing Information and Computer Services)^[7]. Unics could eventually support multiple simultaneous users, and it was renamed Unix.


More Information on http://en.wikipedia.org/wiki/Unix#History

Windows 8 operating system

Microsoft is soon releasing a new version of windows, check it out here Developing windows 8

Mobile networks

Just look at the Motorolla dynatac phone which was released in 1973. It was the first cellular telephone with a battery that wold only last an hour of talktime. I think we are about to back to that generation in terms of size because phones have become big again.