The Berkeley one (which I think may predate the IP implementation) is the one that we know as /etc/hosts that has the address then the namees of the hosts.

The "real" one is the one the NIC put out in the pre-domain days.    It's defined in RFC 952,  looks like

HOST : 10.0.0.29 : BRL.ARPA, BRL : PDP-11/70 : UNIX : TCP :

There was also a simple TCP service that would serve up the file.

I detested the Berkeley one and we always downloaded and used the NIC table on our machines.  I rewrote "rhost" and it's successors (gethostbyname, etc...) to read directly from the NIC format.

Amusingly one day we got an Imagen ethernet-connected laser printer.    Mike Muuss decided the thing should be named BRL-ZAP and since I didn't know what to put down as the machine type, and it did have a 68000 in it, I had Jake put 68000 in the entry in the host table.

The next day I got all kinds of hate mail from other BSD sites who assumed I had intentionally sabotaged the host table.   Apparently, the BSD systems used a YACC grammar to parse the NIC table into the Berkeley one.   The only problem is they got the grammar wrong and assumed the CPU type always began with a letter.    There parse blew up on my "ZAP" host and they assumed that was the desired effect.

I countered back that using a YACC grammar for this was rediculous.   There was already a real popular file on UNIX that had a bunch of fields separated by colons and commas (/etc/passwd anybody) that it was never necessary to use YACC to parse.

-Ron