Debian Support policy

[Rajkumar S <rajkumars@asianetindia.com>]

Hi,

I am doing a comparative study of support times and policies of various 
OS. Windows and RHEL has their policies, including the dates of releases 
and eol, listed at

http://www.microsoft.com/windows/lifecycle/default.mspx
http://www.redhat.com/apps/support/errata/rhlas_errata_policy.html

I know that debian do not follow fixed time lines. but is their any 
rough time frame as to how much time an OS is supported, ie bugs fixes 
are available? Any such policy documents?

Thanks everyone,

raj

PS: I would also be delighted if i get the urls for other OS also 
(MacOS, Mandrake and so on...)