Making an RT-11 boot disk

Jerome H. Fine jhfinedp3k at compsys.to
Tue Apr 10 22:44:19 CDT 2007


 >David Betz wrote:

>>> Okay, I think I see how to do it:
>>> set du0 unit=0, part=0
>>> set du1 unit=0, part=1
>>> set du2 unit=0, part=2
>>> set du3 unit=0, part=3
>>
>> Yes, that looks familiar.
>>
>>> If I do this, I wonder where my RX33 will be assigned. Is it  
>>> assigned du4 since du0-3 are already taken by partitions?
>>
>> Hm....
>> Every MSCP device has a device number. And you have to tell the  
>> driver on which device number and partition it should work.
>> So if your RX33 (what IS that??) has unit number 0, you can create  
>> the devices as above. If you have different drives, you have to use  
>> unit=x.
>
> An RX33 is a 1.2mb 5.25" floppy drive. Actually, I guess I just  
> didn't think hard enough. When I didn't have *any* set commands, the  
> drives were automatically assigned DU0=RD54 and DU1=RX33. My guess  
> then is that the RD54 is unit 0 and the RX33 is unit 1. The suggests  
> that if I just add the line:
> set du4 unit=1
> I should get the RX33 assigned to DU4:
> I guess I should think before I type in questions. Sorry!

Jerome Fine replies:

I suggest that you use:

SET  DU0:  UNIT=0, PART=0
SET  DU1:  UNIT=1, PART=0
SET  DU2:  UNIT=2, PART=0
SET  DU3:  UNIT=3, PART=0

SET  DU4:  UNIT=0, PART=1
SET  DU5:  UNIT=0, PART=2
SET  DU6:  UNIT=0, PART=3
SET  DU7:  UNIT=0, PART=4

I realize that it creates confusion, however, if you
want to do a hardware boot on the RD54, you obviously
BOOT  DU0:

If you want to do a hardware boot on the RX33, you
BOOT  DU1:

If you have booted DU0: (the RD54), then it is quite
acceptable to regard the RX33 as DU4: since the RX33
is just a data drive at this point.  But it will
certainly NOT be possible at that point using V05.03
of RT-11 to command:
BOOT  DU4:  (i.e. the RX33 floppy)
since the set tables on the RX33 floppy MUST have:
SET  DU1:  UNIT=1, PART=0
when you are doing a hardware boot and in order to
do a software boot from DU0: to the RX33 floppy, the
SET values for the device being booted (the RX33 being
the device in question) must be identical to the SET
values on DU0: or the device being booted FROM!

So if you don't want to continually be confused when you
boot from the RX33 which must have:
SET  DU1:  UNIT=1, PART=0
I suggest that you have the identical SET values for DU1:
on the RD54 on DU0:

You will quickly find that under V05.03 of RT-11, you are
ONLY able to boot from a device with a PART=0!!!!!!!!!!!!
This is because the bootstrap program from DEC is missing
one instruction (it was that way until V05.06 IIRC!).  That
missing instruction is in all of my V05.04G files of DUX.SYS,
but I don't thing I ever went back to V05.03 to fix the problem.

Finally, RT11XM.SYS requires device drives with the "X" added to
the device name.  So you will need DUX.SYS, LDX.SYS, VMX.SYS,
NLX.SYS, SLX.SYS, LSX.SYS, etc.

RT11FB.SYS uses the other flavour of the device drives without
the "X" or DU.SYS, etc.
RT11SJ.SYS also uses DU.SYS, etc. and in addition requires TT.SYS
to send to / from the terminal.

All of the device drivers that are used under a given monitor
must be compatible with that monitor.  This allows the RT-11
user to have an RT11FB monitor that is bootable with DU.SYS
and an RT11XM monitor with DUX.SYS with a different set of
characteristics.  When you set up the monitor to be booted
on DU0:, as you have found, BOTH the monitor and the correct
device driver must be present.  But either pair can be used:
COPY/BOOT  DU0:RT11FB.SYS  DU0:  (requires RT11FB.SYS and DU.SYS)
COPY/BOOT  DU0:RT11XM.SYS  DU0:  (requires RT11XM.SYS and DUX.SYS)

Once booted, you can software boot by:
BOOT  DU0:RT11FB
BOOT  DU0:RT11XM
from either DU0: or DU1:

By the way, the RX33 can hold 2400 blocks or almost all of the
V05.03 distribution that runs RT-11.  Leaving out all of the
*.MAC files is probably sufficient.  If you can experiment with
SIMH or E11, it is easier to know what to do on the real PDP-11/73.
Also, have the SET values that same on SIMH / E11 as for the real
PDP-11/73 and that will also make things easier.

You seem to be well along with RT-11.  If you have any more
questions, please ask.

Sincerely yours,

Jerome Fine
--
If you attempted to send a reply and the original e-mail
address has been discontinued due a high volume of junk
e-mail, then the semi-permanent e-mail address can be
obtained by replacing the four characters preceding the
'at' with the four digits of the current year.




More information about the cctalk mailing list