1 Jul
2004
1 Jul
'04
8:01 p.m.
On Thu, 1 Jul 2004, Jerome H. Fine wrote:
A word of caution - For reasons on a PDP-11 which I
don't
understand, the secondary bootstrap program avoids the
VECTORS for the console device at 60,64 and for the
LTC (line time clock) at 100. For all but the MSCP
device driver, the 512 bytes is more than adequate.
This is to allow those
bootstrappers to use interrupt-based
timeouts (ltc) if they want to, and same for papertape-based
loading (console vectors). I have seen only a few bootstraps
actually skipping these locations.
--f