25 Jun
2006
25 Jun
'06
8:13 p.m.
As far as *nix goes, I think Linux just checks the ELF
signature and
executable header checksum. Don't take that as the gospel truth though, I
haven't done any major research into the ELF file format...
OS-90 (at least the 6809 version) checks that the module header is valid,
and then, IIRC, that the module itself has the right checksum. This is
not for any security reason, though, it's because at boot-up, OS-9 checks
all of memory for valid modules. If it finds any, it links them into the
module table, etc. Therefore you can stick OS-9 modules in ROM, just
about anywhere in the memory map, and the OS will find them. Of course to
do this safely, the system has to be very unlikely to consider random
data as a valid module, hnece the check on the header and the module body.
-tony