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