[pups] 2.11BSD boot hangs.

Johnny Billquist bqt at update.uu.se
Tue Feb 27 09:46:45 AEST 2001

On Mon, 26 Feb 2001, Steven M. Schultz wrote:

> > jumper installed. Then I noticed the different setting of the front
> > panel DIP swich. The upper switch is off and the lower on. The switches
> > of the other cabinet are both on. If I boot the machine with W5
> > installed and the upper switch on it hangs. It continues to run
> > immediately if it is switched off. What is the purpose of this
> > switches? 
> 	I suspect that one of the switches enables the line frequency clock.
> 	With out a clock running things will work (at least minimally) as
> 	long as there are some interrupts happening.   

Could be. I also remember seeing somewhere that the two dip switches on
the front panel of BA23 boxes should be set differently for PDP-11s and
VAXen. Appearantly they expect the boot button to behave in different ways
on the bus as well... (and HALT I think)

Don't have that docuemnt anywhere close though...

> 	I vaguely remember that some systems (11/23?) had an externally 
> 	enabled clock and if that switch was not set correctly the OS could
> 	be installed but the system would "hang" later on due to no context
> 	switch scheduling.

That definitely happens for RSX atleast. You *must* have a clock interrupt
running, or you are cooked.

> > Ahh, and an other question: Can the RT11 bootstrap listed in 
> > http://www.ibiblio.org/pub/academic/computer-science/history/pdp-11/bootstraps/mscp_rt11.txt
> > be used to boot 2.11BSD? I have no bootstrap ROM card. (Emanuel, hint,
> 	I think it will work.   2.11 is expecting the registers to contain
> 	the following:
> 		R0 = unit number
> 		R1 = CSR of booting controller
> 	as long as those are set it should not matter what bootcode is used.

Then it's more forgiving than the RSX boot code. I have tried that
bootstrap and it won't boot RSX atleast, that much I know...

Speaking of which; does anyone have boot roms for TMSCP for the M9312?


Johnny Billquist                  || "I'm on a bus
                                  ||  on a psychedelic trip
email: bqt at update.uu.se           ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol

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