FYI: Tornado 2/vxWorks 5.4 (traditional) runs everything in supervisor mode. vxWorks-AE (Advanced Edition) runs supervisor and user. AE is the New Improved vxWorks... while they talk about continuing to support vxWorks 5.4, they are depreciating it and it may become a stripped down version of AE.
All in one mode (supervisor) gives you NO protection between tasks, no hardware protection, you are free to clobber everything and anything. It is less hassle to program and typically runs faster (how much? depends), but much more hassle to debug crashes, less robust, etc. If at all possible, use a protected mode OS (supervisor + user). It will be MUCH more robust. During development, it will catch bugs that you would never notice on an unprotected OS until you have fielded a billion of them and the cost of retrofitting puts you out of business :-(. Well,so I exaggerate. gvb At 10:07 AM 11/2/01 +0530, kirti wrote: >Kirti ------->Normaly we come across 2 modes of operation , user mode & >kernel mode, Is > > > there any OS which provides > > > only one mode of operation ??? I think DOS doesn't support kernel mode >as a > > > seperate mode of operation, does any > > > OS for Embeded has such fearures ?? If anybody knows it then let me >know > > > it. > >Pallav----------> All the RTOS's have only one mode of operation - "kernel > > mode". Eg. VxWorks.Also, I think you could say that DOS only > > provides "Kernel Mode", since User programs are allowed direct > > access to all resources. > > > > > >Do u mean that application running on Vxworks will be running in kernel mode >only ? >But then how do they handle protection of hardware ? If we are not >differentiating bet'n >kernel mode & user mode then lot of protection realted things comes into >picture. > >Actually we are concentrating on developing a OS which will respond like >real time responce, >but its not hard real time , naturally its unix based OS , There comes the >issue of giving dual mode structure. > >Anybody can guide me in this matter ??? > >regards >Kirti ********************************************************************** This e-mail and any files transmitted with it are confidential and may be legally privileged or otherwise exempt from disclosure under applicable law. This e-mail and its files are intended solely for the individual or entity to whom they are addressed and their content is the property of Smiths Aerospace. If you are not the intended recipient, please do not read, copy, use or disclose this communication. If you have received this e-mail in error please notify the e-mail administrator at [EMAIL PROTECTED] and then delete this e-mail, its files and any copies. This footnote also confirms that this e-mail message has been scanned for the presence of known computer viruses. *********************************************************************** -- To unsubscribe from this list, send a message to [EMAIL PROTECTED] with the command "unsubscribe linux-embedded" in the message body. For more information, see <http://waste.org/mail/linux-embedded>.
