1 Jul
2004
1 Jul
'04
9:50 a.m.
Hello list,
I'm trying to figure out the boot sequence on both the RK05 and RL02 drive from a
PDP. Here's how I understand it so far:
1. Get the bootstrap in core either via the FP or PTR.
Or from ROM (originally diode matrix [1]. later on bipolar PROM chips)
[1] Chosen, I am told, because the user could program it without special
equipment like a PROM programmer. All you needed was a pair of cutters
(the 'blank' boards shipped with all the diodes fitted), and a soldering
iron to correct errors.
2. Execute bootstrap and pull in the absolute loader
from 1st. sector of
512 bytes or 256 words;
i.e. copy 1st. sector of drive to core starting from 0
3. Execute absolute loader by a JMP 0.
4. ??? What happens next ???
That clearly depends on what the absolute loader consists of. Presumably
that program will then load the rest of the OS from the appropriate parts
of the disk.
-tony