On Sun, Dec 31, 2023 at 1:27 PM Phil Budne <phil@ultimate.com> wrote:

> arnold@skeeve.com wrote:
> > I am guessing that the original conventions date back to
> > V7 or 32V, but one would have to go looking at code to be sure.
>
> Looking at the hp (RP-04/5/6) man page in V7, 32/v, and 3bsd the
> convention was rpN, where 0 <= N <= 7 were partitions on the first
> drive, and rp8 was the first partition on the second drive.  rp0 was
> root, rp1 was swap, rp2 and rp3 (in the v7 man page) are unassigned.
>
> The rpNx convention, where N is the drive number, with "c" as the
> whole disk is present in the 4.1BSD hp(4) man page.
>

This was just a change to MAKEDEV. The kernel used the same minor
number encoding. 4BSD still used the V7 make script in /dev, but at some
point before 4.1cBSD (I don't have the 4.1BSD exploded locally) it changed,
both in name from MAKE to MAKEDEV and to start the [a-h] suffix for
partitions.

Warner