[svlug] help transfering data over 1394 cable

[Daniel Gimpelevich]

On Fri, 09 May 2008 02:59:36 -0700, Rick Moen wrote:

> Oh?  _One_ of us provided correct information and a complete recipe for 
> moving the file with the desired speed advantage and avoidance of
> pointless complexity.

Although you provided correct information, it was I who at least attempted
to avoid pointless complexities, such as creating a new private network
segment connected through a semi-private network segment.

> The other of us compared rsync to ssh as
> alternatives (possibly not being aware that the first runs _over_ the
> second) and advised Christian he'd have to find an "rcp daemon" [sic]
> before he could run rcp.

The first is not required to run over the second (in general, current use
case notwithstanding), and is slower than scp/sftp/fish either way _at the
application layer_. Since sshd is the daemon that handles both scp and
sftp (and by extension, fish), it may be described with some accuracy as
the "scp daemon" or even the "fish daemon," since correct terminology here
is also a pointless complexity. Rsh and rcp work the same way, as anybody
attuned to the history of ssh knows. From my saying he'd need an "rcp
daemon" when I did, he'd instantly see rcp as pointlessly complex, whereas
if I said "rsh daemon," he'd first probably ask "Why do I need rshd for
rcp?" and only decide that rcp is pointlessly complex upon getting the
answer. Know your audience.

>> I intentionally avoided the above point for brevity.
> 
> I believe you misspelled "I gave Christian misleadingly bad information
> on a subject I was already aware I knew nothing about."

Wow, I never thought you'd stoop to intentional libel on a public mailing
list... (Yes, I'm fully aware of what you always say about that.)

>> > and the need to move 1.5 TB of video
>> > files over a private network segment would seem to qualify, too.
>> 
>> Did anybody mention that the network segment is _not_ private?
> 
> Irony alert:  You're recommending _NFS_ for that?  The No Friggin'
> Security filesystem?

OK, I see how my urging one to seek information about NFS may be
misconstrued as a recommendation to use it in the given case. I'm often
unclear in what I say. I mentioned NFS as counterpoint to rsh/rcp, and
warned about it not being "perfectly suited to this."

> I was, in fact, going to get around to pointing out precisely that flaw
> in Christian's plan:  If he's going to connect the two machines to a
> switch that's connected to public networks, then the only network
> mechanisms he could reasonably use to move his 1.5 terabytes of video
> files would be cryptographically authenticated ones such as scp, sftp,
> kerberised ftp, or ftp-ssl (or variants such as FISH).  Which, again,
> means he'd better cultivate a _real_ sense of patience, since the
> transfer is going to take geologic time.

Wanna know where he came up with the idea of using FISH for that? From
_that_ being what I recommended, for precisely the above reason, despite
my opinion that nobody would be masochistic enough to want to reconstruct
DV data from a packet dump, anyway.

> _Or_ he can do the sensible thing and go buy or borrow a $20 second
> ethernet card, so that the data transfer can be over a private network
> segment after all, and thus use reasonably fast transfer mechanisms
> without exposing his systems to bend-over security.

Since the non-private network segment is what assigns 10.x.x.x addresses,
that would require setting up an addressing system (read: deciding on a
couple of numbers exactly once) for the private segment, which if you
remember, was the original reason he decided against Firewire. Yes, he'd
need that for a crossover cable, too (since that is also a private network
segment after all), but he hasn't grokked that yet.