[HECnet] DECdns

[Johnny Billquist]

On 2016-05-31 17:10, Dave McGuire wrote:
> On 05/31/2016 10:41 AM, Johnny Billquist wrote:
>>> At the time DECdns was designed, the Internet's DNS was basically just
>>> a text file connected to a trivial daemon, with updates done by
>>> sending new versions of those text files around.  That was roughly the
>>> same level of primitiveness that the DECnet Phase II through IV node
>>> name mappings had.  DECdns delivered a distributed database with
>>> automatic machinery for distributing updates reliably.
>>
>> However, your description and/or understanding of DNS seems to be very
>> weird. DNS have never been just a text file connected to a daemon. It
>> sounds like you are conflating DNS and the pre-DNS /etc/hosts (or
>> HOSTS.TXT) file, that was used in the early days. Which might match the
>> time frame of DECdns. The HOSTS.TXT file was not even connected to any
>> daemon. Your programs were expected to just read and parse the file
>> themselves, as needed. Or at least on the systems I know about. Exactly
>> how this worked could differ from one system to the next. But there
>> wasn't anything called "DNS" at that time.
>
>   Actually, it actually was just a text file connected to a daemon.  I'm
> not talking about HOSTS.TXT, I'm talking about BIND.  And, at least in
> the case of master servers, this is still the case.  Slave servers no
> longer store their replicated data as text files, and even when they
> did, it was a bit more complex than simply "sending the files
> around"...they were (and are) parsed, transferred in binary form, and
> re-created on the other end.  Except now, they're stored in a binary
> form in the filesystem on the other end.  But Paul's description is, in
> essence, correct.
>
>   The daemon has been anything but trivial for 20+ years, and is
> unbelievably complex now.

The problem with Paul's description was not what the local backing store 
looked like, but how it was distributed. As you yourself says, it is not 
distributed as a plain text file.

The comparison to how nodenames in DECnet was done is very much on par 
with the old HOSTS.TXT file, but not at all comparable with DNS.

>> DNS is distributed, with automatic updating of secondaries from
>> primaries. It is rather fault tolerant, and very scalable.
>>
>> The one thing "lacking" have been an easy way of adding new information
>> programatically, while at the same time ensure security and data
>> validity. So you often still have the source of information for the
>> primary server being managed in a text file. But that file is not sent
>> around to other servers of the domain. DNS takes care of distribution
>> and replication itself.
>
>   All of that works quite well now.  The security of dynamic updates
> could be better, but it works, and signed zones work well (but are
> difficult to set up).

Yeah, I know this has been improved lately, but this has, for a long 
time, been one of the biggest complaints about DNS.

	Johnny