Re: Ada-inspired OS/Language

[sam@rfc1149.net (Samuel Tardieu)]

"Warren W. Gay VE3WWG" <ve3wwg@cogeco.ca> wrote in message news:<3D628304.3040506@cogeco.ca>...

> Now we've regressed with the palms etc., back to this no-protection model.

Are you referring to Palm Inc. handhelds? (if you aren't, let's blame
the language barrier and ignore the rest of this message :-).

If this is the case, this is unfair to Palm Inc. Their handheld
devices contain a chip which prevents memory writes outside of the
heap (only one application can be running and thus access the heap at
a given time, and the stack is located in the heap space). When an
application wants to write into a so-called database (for example
another application or users persistent data), the PalmOS system call
checks the address, directs the external chip not to intercept the
next write operations if the address is correct (previously locked
memory chunk), do the write then tells the chip to prevent further
write operations in non-heap areas.

They do not have true memory protection (which would be useless in
their case), but they do offer a working alternative. That is why
their devices almost never loose data, even when they run bogus
applications (which can cause a data-safe device reset).

  Sam
-- 
  Samuel Tardieu -- http://www.rfc1149.net/sam -- sam@rfc1149.net