combined hardware-virtual isolation

addm/security/combined hardware-virtual isolation:
2.9: 3.31: intro:

. certain attributes of data are essential to security;
eg, by retagging arbitrary data so that it is
usable as a pointer to code,
we can treat malware data as instructions to follow .
. generally all data can be tagged
just as it is done by xml .

. there are 2 possible ways to enforce
process isolation and ROM attributes:
# HW (hardware) mem'mgt,
# VM (virtual machine) mem'mgt .
. hardware mem'mgt can enforce VM mem'mgt:
the VM's run-time exec never needs to change;
so, HW mem'mgt can see that code as const;
also, any file that the VM is trying to interpret
can be treated by the HW mem'mgt as
something that only the VM process can modify .
. finally, the VM has its own process space
and this should keep other processes
from corrupting its work space .

Ada's core attributes

8.20: web.adda/ada/predefined attributes:
. what are Ada's reserved attributes?
here they are renamed for clarification
(these are just the most basic ones;
there are many more for floats, etc):
type'base  -- the unconstrained subtype;
enum in type'first .. type'last,
A'range(N) =  A'first(n) .. A'last(n) -- array's nth dimension;
type'value(enumcode number or image string);
type'image(value) is a string;
type'code(value) -- the integer representing the value (aka pos);
type'codebitsize -- obj's fixed size (when packed);
rec.component'codebitoffset;
type'imagesize -- #characters(for largest expression);
type'++(value) -- successor;
type'--(value) -- predecessor .