--- "Steven M. Bellovin" <smb@cs.columbia.edu> wrote:

> In message
> <BAY17-F17C3D220CEF5F1DDAB4767C36E0@phx.gbl>, "Jared
> Momose" writes:
> >Kamal,
> >
> >I have been thinking about this problem for a
> while, considering the 
> >Blackfin line of DSPs from Analog Devices. These
> processors are similar to 
> >what you describe in that they have address
> protection but not translation. 

Yeah -Im referring to blackfin.

> >Without translation, you are doomed some nasty page
> swapping madness. You 
> >might be able to minimize it by attempting to
> locate your binaries to 
> >different addresses such that concurrently running
> binaries occupy different 
> >sections of your address space, but you still have
> severe limitations 

Not a problem if you consider that:-
(1) there is no swap device
(2) all binaries are loaded from flash on bootup and
seldom removed before shutdown.

> >(multiple instances of the same programe, i.e.
> getty, anything multiuser, 
> >fork needs to be reworked?!). Personally, I have

do we need getty() on a dsp?

> concluded that although it 
> >may be possible, the result would be terribly
> inefficient and not very 
> >useful for anything academic or commercial.
> >
> 
uclinux is the modified version of linux that is
commercially used.

> Let me dredge up some ancient technology.... 
> OS/360, vintage 1965 or 
> so, had memory protection but no virtual memory of
> any sort.  However, 
> executables were relocated at program load time. 
> This imposes a 
> requirement on both the linker and the program
> loader, of course.  

there is a gnu toolchain for uclinux that can be
re-used. I have it compiled on netbsd2.0-i386.
http://blackfin.uclinux.org

provides more info on the same.

regards
-kamal


=====
------------------------------------------------------------
Kamal R. Prasad
UNIX systems consultant 
kamalp@acm.org

In theory, there is no difference between theory and practice. In practice, there is:-).
------------------------------------------------------------


		
__________________________________ 
Do you Yahoo!? 
Yahoo! Mail - Find what you need with new enhanced search.
http://info.mail.yahoo.com/mail_250