PDP OS Boot Sequence: WAS Re: RK05/RL02 Boot Sequence

From: Paul Koning <pkoning_at_equallogic.com>
Date: Tue Jul 6 10:37:05 2004

>>>>> "Megan" == Megan <mbg_at_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
Received on Tue Jul 06 2004 - 10:37:05 BST