[mythtv-users] Mooting architecture for a DataDirect replacement
mythtv at rodsbooks.com
Wed Jun 27 02:36:51 UTC 2007
On Tuesday 26 June 2007 21:59, ICMan wrote:
[re: Using the DNS protocol, but not the existing DNS hierarchy, for data
> The "name" of the station/server/service
> bounds the data. A server could be authoritative for more than one
> domain (ie. station). Perhaps the station names could be delegated by
> the cable/feed company names (Rogers-Toronto, Star Choice-Chicago,
This could be an appealing aspect of this approach. It could make retrieving
data by station pretty painless. In the case of NNTP, you'd presumably need
to encode the station ID in the subject header (or possibly some other
header), which is a bit unaesthetic.
> I know Jay is flogging NNTP, but I just don't see how you get accurate
> listings, a complete lineup,
These issues aren't any better or worse for NNTP vs. DNS (vs. most other
protocols); these issues relate more to the data collection end of things
than to the data distribution method used.
> JIT listing changes, etc.
Usenet posts tend to propagate fairly quickly through the Usenet network, and
the load balancing is such that it shouldn't be a big strain on local NNTP
servers to have Myth boxes checking for new posts in a handful of newsgroups
every few minutes. To be sure, dissemination won't be instantaneous, but it
could be pretty quick -- on the order of a few minutes to an hour or so, if
users' boxes check their NNTP servers every few minutes.
> Would the
> proposed solution put an NNTP server at every station, or would they use
> existing commercial NNTP servers to propogate changes?
Either method would work, as would our providing an NNTP server for this
specific purpose. Chances are most stations wouldn't want to install and run
an NNTP server on-site, so it'd probably be an off-site server -- if the
stations even contributed data directly (they might not, as some recent posts
> How do you
> ensure everyone with a public NNTP relay carries the appropriate news
Most Usenet news server administrators will add a new group or group hierarchy
upon request, provided it's not something that'll overload their system or
otherwise cause problems.
> How do we tell people what news servers to point to?
This could be a challenge, but not an insurmountable one. One approach would
be to have the Myth system probe for appropriate servers, given the user's
domain name (or ISP's domain name). For instance, if you say your ISP is
example.net, it might probe nntp.example.net, news.example.net, and perhaps a
few others. This will auto-detect the correct server a good portion of the
time. The code might even include a lookup table for some common ISPs. Beyond
that, you'd need to tell users to contact their ISP and/or subscribe to a
commercial Usenet provider -- or if we run our own NNTP server, configure the
system to use it.
> Will NNTP
> server administrators freak over the increased load on the servers that
> contain MythTV Listings Newsgroups?
No. The extra load would be pretty small by Usenet standards. Somebody
computed the data storage requirements for the whole project as being in the
low hundreds of megabytes (per 2-week period, IIRC, which is all that would
have to be cached). I've got a Leafnode server locally, which is a small
cacheing NNTP client/server for personal use. It's currently got 22MB of
files in its cache, and I only subscribe to one or two dozen text-only
newsgroups. Much of Usenet is binary newsgroups, and some of those can easily
run into the gigabytes of storage per day. Any news server that carries any
but the tiniest binary newsgroups won't even notice the spike in traffic that
TV listings would cause.
As a side note, with the MythEPG mailing lists now up and running (although I
have yet to receive a post on them), how should we begin moving these
discussions to that list (or should we)? I considred "cross-posting" (to use
the Usenet term) this reply, but I'm not sure that would be considered good
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