OS stands for operating system. In simple terms this is the main program the computer runs. As far as any computer's concerned, when it's doing anything, that's the operating system. An operating system could be any program. If you wrote an embedded computer program to manage a thermostat for your home, that's an operating system. It's what runs on the CPU.
With a regular OS, time is NOT as important. It can take three seconds to return a value from an extremely complicated function. Five seconds to go to the USB port and obtain data from an external device. Real-Time OS's have a far more constrained view. Time is of the essence. A real time OS is commonly an embedded operating system, such as the above mentioned thermostat. When you push the button on the box, you want to see the current temperature in the room NOW. Not in 3 seconds. Not after the "loading" icon has flashed a few times. Now. Everything is based on time, because when the program that determines that the radiation level in the research facility's nuclear reactor has gone above the value expected, it must respond immediately. When your tires lock up in your Anti-Lock Brake system, your computer in your car (yes, there is a car in the computer) needs to react immediately. For more information on real time operating systems, I recommend: http://linuxdevices.com/articles/AT4627965573.html And other articles on the linuxdevices website. Have fun! ----- Original Message ----- From: "Prasad Mehendale" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Tuesday, October 26, 2004 10:17 Subject: [Freedos-user] What is OS ? > Hallo all ! > I hope I am not asking an Off Topic question. > I am a designer of microcontroller based systems, and prefer to write in assembly for speed and small size. > I never learned anything about an OS systematically though I used some (dos & linux). > My question is- > Is it possible to describe an OS in short ? If yes, can any one do this for me? You also may provide some link on net. > I am interested in knowing the difference between the RTOS and the one we frequently use. > I have fair understanding of internal hardware and architecture of micro-processor and controller. Is it sufficient to understand what an OS is ? One may describe all this with reference to Freedos. > Thanks again. > > Prasad Mehendale > > > ------------------------------------------------------- > This SF.net email is sponsored by: IT Product Guide on ITManagersJournal > Use IT products in your business? Tell us what you think of them. Give us > Your Opinions, Get Free ThinkGeek Gift Certificates! Click to find out more > http://productguide.itmanagersjournal.com/guidepromo.tmpl > _______________________________________________ > Freedos-user mailing list > [EMAIL PROTECTED] > https://lists.sourceforge.net/lists/listinfo/freedos-user ------------------------------------------------------- This SF.Net email is sponsored by: Sybase ASE Linux Express Edition - download now for FREE LinuxWorld Reader's Choice Award Winner for best database on Linux. http://ads.osdn.com/?ad_id=5588&alloc_id=12065&op=click _______________________________________________ Freedos-user mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/freedos-user
