6 Jul
2004
6 Jul
'04
3:37 a.m.
>>>> "Megan" == Megan
<mbg(a)theworld.com> writes:
> Any ideas as to where can I get more details on
the various OSes
> boot sequence on the PDP11?
>
> Should have details like what disk block goes to which core
> address, how to find/load/jump to the kernel..etc.
Megan> Typically, for the -11's, the first block (block 0) of the
Megan> device is loaded at address 0. The DEC bootblock standard
Megan> calls for the first word to be a 5 (reset) and the second to
Megan> be a branch to the rest of the code (so that locations 4/6 and
Megan> 10/12 at a minimum are free for non-existent memory and
Megan> illegal instruction traps).
That doesn't match what I learned (or what's in RSTS 10.1). The reset
in location 0 was an old convention. But when a real boot block
standard appeared, it said that 0 had to be a NOP, and 2 a branch to
the setup code. Also, there had to be a "Szeto ID area" just before
the branch target.
As a special case, PRO boot devices must have a HALT (0) in word 0 --
obviously the ROM boot transfers control to 2 and not 0 as on other
PDP11s.
paul