2.11BSD Device Names

[Glen Slick]

On Thu, Sep 15, 2016 at 1:08 PM, David Coolbear <david at thecoolbears.org> wrote:
> For 2.11BSD on the PDP-11, in the stand alone utilities that are found on
> the installation tape, the storage devices are named:
>
> dn(x,y,z) where dn is the mnemonic for the driver, x is the controller
> number, y is the unit number and z is the partition on the unit. So the
> first partition on the first drive on the first MSCP controller is
> ra(0,0,0). It's fairly easy form the install tape to disklabel and mkfs a
> drive on a second controller.
>
> Once UNIX is running, things change. The devices in /dev are named ra0 for
> the first unit on the first controller, ra1 for the second unit on the
> first controller and etc. I don't see a way in the naming convention to
> identify other controllers.
>
> My question is, what is the device name in /dev for the first drive on the
> second controller?

man ra

major device number(s):
raw: 14
block: 5

minor device encoding:
bits 0007 specify partition of RA drive
bits 0070 specify RA drive
bits 0300 specify RA controller

ra{0-7}{a-h} would be the 8 partitions on the 8 drives on the first controller

ra{8-15}{a-h} would be the 8 partitions on the 8 drives on the second controller

ra{16-23}{a-h} would be the 8 partitions on the 8 drives on the third controller

ra{24-31}{a-h} would be the 8 partitions on the 8 drives on the fourth
controller.

ls -l /dev/*ra*

If you don't see the device you need than you can use /dev/MAKEDEV to
create it with the appropriate major and minor device numbers.