Re: [LIP] Resident function using c/c++

sameer oak wrote:
>>Yes. They are called daemons.
> 
> ...
> FYKI, daemons are not TSR programs. and UNIX doesn't support TSR
> programs.

If your definition of TSRs is based on how they work, rather than what 
they achieve, I will have to agree with you. Daemons don't exit like 
TSRs - they simply let go of the terminal.

TSRs are not a "feature" provided by DOS but a poor hack for achieving 
multi-taksing under DOS, since the..er..DOS scheduler [for the lack of a 
better term] only allows only one process to run at a time, and so a 
process which needs to continue to run needs to indicate to the 
scheduler that it's exiting, while hooking into some interrupt to 
be..er..resurrected.

If you want to have TSR like behaviour - essentially running in the 
background, without being listed in any process/module table, check out 
the code for some rootkits, which do exactly that.

> this's one of the reasons why UNIX did not support execution of virus
> programs.

Ahh...I always knew there were some features missing in *nixes - not 
"supporting" virus execution is certainly one of them.

Perhaps a better security model - specifically kernel/userspace 
separationa and user privileges is a better explanation of why viruses 
haven't caught onto *nixes.

Remember, worms, trojans & rootkits exist for *nixes - they don't spread 
like viruses though.

> though, there are loopholes and hackers find the way through.

-- 
Regards,
Varun Varma
---------------------------------------
Mindframe Software & Services Pvt. Ltd.
http://www.mindsw.com
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