Mail cost

[boomslang]

Originally posted by Supplement Four:
</font><blockquote>quote:</font><hr />Originally posted by Andrew Boulton:
Xmail: Messages sent by xboat. Xmail carries information only; material objects may not be sent. The message is digitally coded; xmail costs CrlO per 20 kilobits per parsec. The message may be sent using a standard Anglic character set (about CrlO for a 500 word message) or a picture may be reproduced in facsimile (Cr20 for a 200 x 200 bit matrix). The message is printed out at its destination and delivered by a world's local mail system.

</font>[/QUOTE]That's so painfully outmoded. Moore's Law, et cetera, et cetera...

A Type X carries 17 dtons worth of "data banks". A terabyte hard drive here at early TL8 is the size of your lunchbox. Thousands of them will fit into a single dton. Ramp the tech up to TL14 (needed for Jump-4), and a single Xboat is probably carrying an exobyte of data or more.

And the kicker: the computer was going to be booted up and making the trip anyway, the actual carriage cost is zero Credits.

IMTU, I figure a modest Cr1 per gigabyte-parsec is reasonable-enough to foster and encourage interstellar communication, yet still produce a breathtaking revenue stream for the noble families. Maybe a Cr1 per terabyte-parsec rate could be considered for non-government use, to further promote private use.

The problem comes on the uplink/downlink end of the Xboat operations. Trasmission of an exabyte of data in the few minutes it takes and Xboat to hurriedly refuel and replot for the next Jump takes a spectacular amount of bandwidth. We're talking spinal-mount-weapon energy levels here. Even if an Xboat could generate that kind of power, the antenna's backscatter radiation alone would produce a freshly-grilled Scout in moments. ("Crew-1" on the radiation damage table, as it were.)

Plain ol' Mail on the other hand is a true cash cow; forget landing the Mail Contract to defray operating costs on your Subbie -- what you want is to land the Post Office Contract for a busy-but-low-government world. Charge an exhorbitant (but pro-rated) Cr100 per kilogram-parsec for small parcels (including, ironically enough, digital media), and you will make enough money to own your own fleet of Mail Packets in no time.

Then you can laugh at all the chumps hauling freight and passengers for peanuts... and even at the losers who think they've lucked out because they get a whole Cr25000 (and that's not even per parsec) every time they haul Cr500000+ worth of small packages for you...

No wonder some governments don't mind operating their Subbies at a loss, eh?

 

[Straybow]

Bandwidth: That's the reason why you put the data in a "drive" (could actually be some kind of solid state permanent memory) and transfer the drive. You need a larger space (not necessarily 17 dTon) because every downstream destination world (say, one third of 11k worlds on average) needs a separate package.

 

[RainOfSteel]

Originally posted by boomslang:
Ramp the tech up to TL14 (needed for Jump-4)

Since when?

Book 2 doens't have TLs involved with drives, and Book 5 says Jump-4 is available at TL-11.

Though that does raise the separate issue of why Supplement 9: Fighting Ships, says the X-Boat is TL-10. It wouldn't be the first typo in that book. The ship is really probably TL-11.

Originally posted by boomslang:
Trasmission of an exobyte of data in the few minutes it takes and Xboat to hurriedly refuel and replot for the next Jump [...]

What? A few minutes? No, I think they sit around for longer than that. The tender has to come get it first. Given jump error margins and the slow acceleration of the tender, that's going to leave some time open (more than a few minutes).

Ship to ship refueling also probably takes more than a few minutes, as well.

The X-Boat can be simulatenously uploading and downloading during both waits.

If it activiates a thousand communications channels (in its TL-11 comm system) at once, each one carrying a high-speed compressed data stream, I don't think it will be a problem when you look at today's communication systems vs. what will likely be available 2-3 TLs down the road.

Also, each X-Boat is unlikely to unload its total data store at each stop.

I even doubt that each X-Boat runs around with a fully loaded data store.

Originally posted by boomslang:
[...] takes a spectacular amount of bandwidth. We're talking spinal-mount-weapon energy levels here.

I'm going to have to say I have that I doubt that. I strongly doubt it.

Can you toss some math out here?

 

[boomslang]

Originally posted by RainOfSteel:
</font><blockquote>quote:</font><hr />Originally posted by boomslang:
Ramp the tech up to TL14 (needed for Jump-4)

Since when?</font>[/QUOTE]HG2, pg. 23. TL13, actually (my bad).

The ship is really probably TL-11.

TL10 will do it, for the Model/4. (Magical and Wonderous Jump-drive-B that requires no powerplant notwithstanding.)

And now, some math:

An exabyte is a billion gigabytes. To trasmit that using EM radiation requires a (combined) signal that can be modulated very fast: you cannot trasmit data at more than twice the Hertz without loss (which is unacceptable in this application).

Suppose the Xboat needs to dump a mere 1 million gigabytes (a petabyte) into the next outgoing ship (0.1% of its assumed capacity).

At bandwidth of one gigabyte a second, that takes on the order of two weeks, and requires a GHz signal. If we split into 1000 channels, averaging a GHz in frequency, it can be done in maybe 15-20 minutes, moving a terabyte a second.

But it's generating those 1000 1-GHz channels that takes a big transmitter. And, as you recall, Xboats don't even have powerplants, much less gigawatt radios and gigantic receiver-transmitter arrays. And the 1GHz range is getting up into infrared, which is not optimum for long-range transmission. You'll want to back down into radio frequencies, or at least microwaves.

So now we're talking a 10000-channel microwave transmitter that can move a terabyte per second using several gigawatts of power. That's a pretty good spec for a weapon, as well. Depending on how much leakage you get from your antennae, it's going to be something you want to keep anything with water in it quite well away from.

If you want to minimize backscatter and all, you can go with masers instead of mere microwave radios, but now that's really looking like a weapons system.

The Netflix hypothesis still holds: it's probably cheaper and faster to just swap out the databanks using removable media; a Ship's Boat, for example, could shuttle back and forth between an incoming and an outgoing Xboat, swapping out hardware with much less overhead.

 

[far-trader]

Originally posted by RainOfSteel:


Book 2 doens't have TLs involved with drives, and Book 5 says Jump-4 is available at TL-11.

Though that does raise the separate issue of why Supplement 9: Fighting Ships, says the X-Boat is TL-10. It wouldn't be the first typo in that book. The ship is really probably TL-11.

It's TL10 because as a Book 2 design in Supp 9 because of the Model/4 Computer.

And the magic jump drive that needs no powerplant is a first edition Book 2 design quirk, later changed but the X-Boat was never fixed for that either (since it wouldn't have worked).

Agreed, as a Book 5 build it would be TL13 for the J4 but you also end up with enough space for a maneuver drive which raises more disturbing questions than the simple TL issue.

Not that there aren't already a host of questions to be ironed out between Book 2 and Book 5...

 

[Spinward Scout]

Hmmm... This is interesting. I wonder why no one's ever really thought it through before. 30 years of Traveller and nobody went 'hey, just a minute...' It would add to the data load if all of the x-mail packets were encrypted as well.

It WOULD be easier to swap the data 'sachel' from one pony... er... x-boat to the other. A mating of both ships seems to me to be the best method. But we'd be moving away from 'canon'.

 

[RainOfSteel]

Originally posted by boomslang:
HG2, pg. 23. TL13, actually (my bad).

I was looking at the wrong chart.

Originally posted by boomslang:
But it's generating those 1000 1-GHz channels that takes a big transmitter.

Since when?

My cordless phone is a gigahertz radio transmitter. At TL-8. At higher TLs, that'll be a lot smaller and more power efficient.

Size is not necessary to generate higher frequencies.

Size is necessary to generate lower frequencies, that's why ELF transmitters are miles long.

Now, to trasmit in quality over a distance, that requires technical precision and quality components, and higher power, but not gigawatts of it. A gigawatt tranmitter would be suitable for transmission at interstellar ranges. Little X-Boats don't need anything of the kind.

Originally posted by boomslang:
And, as you recall, Xboats don't even have powerplants

That has been the subject of massive debates going back decades.

Please be aware that the Book 2, Book 7, Book 9 X-Boats are all generally viewed as mistaken or otherwise stupidly impossible (not to mention rules-violating).

Considerable time has been given over to designing far more probable X-Boats that are actually rules legal.

Originally posted by boomslang:
[...] much less gigawatt radios and gigantic receiver-transmitter arrays.

You don't need a gigawatt radio to transmit gigahertz frequencies.

Originally posted by boomslang:
And the 1GHz range is getting up into infrared,

Then how does my 5.8 GHz cordless phone work? It's not by infrared.

And what is this site about60-GHz CMOS Radio Systems, then?

Or this site, Welcome to the U.C. Berkeley UWB Group?

-----------------------

In any event, a multi-channel laser comm system surpasses radio constraints.

 

[RainOfSteel]

Originally posted by The Traveller Formerly Known As...:
It WOULD be easier to swap the data 'sachel' from one pony... er... x-boat to the other. A mating of both ships seems to me to be the best method. But we'd be moving away from 'canon'.

I just don't think that is necessary.

A blue or ultraviolet frequency multi-channel laser comm could transmit larger amounts of information in comparison to radio.

 

[Spinward Scout]

I see your point with your last post. Pairing up for the transmission is what we're looking at then. A broadcast wouldn't be precise enough.

 

[boomslang]

Originally posted by RainOfSteel:
My cordless phone is a gigahertz radio transmitter. At TL-8. At higher TLs, that'll be a lot smaller and more power efficient.

And it has a 50000km or even 500000km range from its base? I don't think so... look on the bottom and see what its wattage is...

Wavelength isn't the issue; transmission power and reception sensitivity are... the Inverse-Square Law and all that jazz...

 

[boomslang]

Originally posted by The Traveller Formerly Known As...:
Hmmm... This is interesting. I wonder why no one's ever really thought it through before. 30 years of Traveller and nobody went 'hey, just a minute...' It would add to the data load if all of the x-mail packets were encrypted as well.

Wait, you mean you don't encrypt all your data streams by default?



Clearly the "interstellar fax machine" model of Xboat communications yields to the "large-packet-size e-mail" model, but a good encryption algorithm shouldn't more than quadruple the original data length, regardless of key length.

 

[aramis]

Originally posted by Icosahedron:
... if interstellar mail is so cheap (and even then makes billions for the X-boats) why would travellers pay 20-120Cr to a total stranger to carry a letter for them?

To avoid formal tracking of the letter. Avoiding the evil empire.
To reduce the number of potential leaks so that they may be eliminated if the delivery is botched.

Deniability...

 

[aramis]

Originally posted by boomslang:
</font><blockquote>quote:</font><hr />Originally posted by The Traveller Formerly Known As...:
Hmmm... This is interesting. I wonder why no one's ever really thought it through before. 30 years of Traveller and nobody went 'hey, just a minute...' It would add to the data load if all of the x-mail packets were encrypted as well.

Wait, you mean you don't encrypt all your data streams by default?



Clearly the "interstellar fax machine" model of Xboat communications yields to the "large-packet-size e-mail" model, but a good encryption algorithm shouldn't more than quadruple the original data length, regardless of key length. </font>[/QUOTE]If one is compressing or encrypting, one may as well do the other...

 

[rancke]

Originally posted by boomslang:
That's so painfully outmoded. Moore's Law, et cetera, et cetera...

A Type X carries 17 dtons worth of "data banks". A terabyte hard drive here at early TL8 is the size of your lunchbox. Thousands of them will fit into a single dton. Ramp the tech up to TL14 (needed for Jump-4), and a single Xboat is probably carrying an exobyte of data or more.

That's assuming that the computer technology of the Real Universe Earth today is only TL 8. This is not necessarily so. One possible explanation for why the TU Earth was more advance in space technology is that the efforts we put into the computer revolution went into space technology instead. Real Universe Earth could have a computer tech level of... well, I don't know, but higher than 8.


Hans

 

[RainOfSteel]

Originally posted by boomslang:
</font><blockquote>quote:</font><hr />Originally posted by RainOfSteel:
My cordless phone is a gigahertz radio transmitter. At TL-8. At higher TLs, that'll be a lot smaller and more power efficient.

And it has a 50000km or even 500000km range from its base? I don't think so... look on the bottom and see what its wattage is...

Wavelength isn't the issue; transmission power and reception sensitivity are... the Inverse-Square Law and all that jazz...
</font>[/QUOTE]

Originally posted by RainOfSteel:
Now, to trasmit in quality over a distance, that requires technical precision and quality components, and higher power, but not gigawatts of it. A gigawatt tranmitter would be suitable for transmission at interstellar ranges. Little X-Boats don't need anything of the kind.

 

[boomslang]

Originally posted by RainOfSteel:
A gigawatt tranmitter would be suitable for transmission at interstellar ranges. Little X-Boats don't need anything of the kind.

Well, not if they have gigantic receiver antennae in order to yield the necessary gain -- but we're back to a trade-off: if you're going to move a terabyte per second over GHz multifrequencies either you have a high-power transmitter or else you have a huge receiving dish. You can't have high bandwith and a low-power transmitter and a small receiving dish; something's gotta step up. The bandwidth is non-negotiable, and Xboats have small dishes, ergo...

 

[BillDowns]

I would imagine laser transmissions would be used. That would require more accuracy, but less power - Inverse square doesn't apply to coherent lasers.

To increase the data rate, a small cluster of 10 lasers could be used to transmit error-corrected byte-wide data, and reduce the time by a factor of 8.

 

[Spinward Scout]

If I remember correctly, the X-Boat Tender has a big receiver dish...

 

[robject]

I suggest that the high-bandwidth transmitter installs into the lone hardpoint on the Xboat. Or perhaps it's three bitcasters in a triple turret.

 

[Gnusam Netor]

Bitcaster...