Surely this type of service is great in an asynchronous environment, but aren't the vast majority of fat pipes around the world are upload capped?
as the number of users increases, surely the sum of the bandwidth downloading will ultimately be limited by the bandwidth uploading - not a problem at the moment as there are a good number of people on t1s etc, but as more and more people use the service, is this not going to become a problem?
In answer to your question: Civil Aircraft navigate using a variety of methods. Depending on where in the flight programme these are, this could be anything from VOR (Very High frequency Omni Directional Range) system to a Heading Select system ILS system or ADF. The Nav system itself functions using a variety of inputs including VOR (Military systems operate on TACAN (Tacital Area Navigation) which uses UHF rather than the mid band frequencies that VOR uses), Compasses, Accelerometers, Gimballs, Gyros as well as Ground Mapping RADAR fixes, GPS (these days), JTIDS (Joint Tactical Information Distribution System -Military again), On-Top fixes, HUD fixes and Offset fixes in addition to ADF (automatic direction finding)
These inputs are used for comparison within the autopilot which uses a triplex (usually) voting system to decide what to show and what to do. (obv this various from system to system)
So, finally, in response to your question, yes the plane does use a compass to navigate and whilst all these sub-systems are designed to promote redundancies within the larger system, they are taken into account and in the event of a larger systems failure, may be relied upon more than the pilot may realise - hence one of the major problems in over reliance on redundant systems...your perceived level of safety increases thereby causing you to change your actions accordingly and hence reducing the overall safety of the craft. - But thats another story.
Incidentally, the reasons for not using cell phones on planes are neatly put at this link Airborne operation of PEDs [PDF]
(I am not a pilot)
ipfw rules
sudo ipfw add 08800 deny tcp from any to any portnumber in via en0 for wired connections
If i remember correctly...
You will have to edit the ipfw file to get it to remember this on startup though...
sudo pico/etc/ipfw.conf
In this particular case the problem is appletalk routing. Since you are creating a local subnet using the PowerMac as the router, you probably have appletalk activated on the wrong network interface. It needs to be on the Airport ethernet only and not on the wired connection. It can only be on one at a time so just switch it. - incidentally this won't change your ability to share info with the airported computer. You could also try blocking access to the appletalk port (548 IIRC) on your built in firewall.
Alternatively, get a proper hardware firewall and use that to mask your subnet.
Ultimately you need to be careful what services you enable on which interface as one of them is visible to the world and one isn't.
Principally you have 2 problems. One is who would buy it, you are transsonic,so you have to fly over desert or ocean so you are limited to certain routes (as you say, but it limits the market dramatically). The other is the fact that the fuel consumption is not associated with the high cruising speed, but the getting to that speed.
The difference in economy associated with a lower speed design is in fact not huge. once you are supersonic you are supersonic and its crossing that barrier that poses the problems. the real engineering barrier is above m2.2. thats when you start to get into real trouble requiring new materials and cooler tech.
1. depends on the coefficient of friction.
2. concorde flies at twice the altitude of other aircraft where the air is pretty thin....
3. besides which there is a lot more to drag than just skin friction...induced drag etc...
of course roughly speaking makes all this pretty irrelevant since the olympus engine is a beast.
You would expect there to be a revolutionary new plane out in the skies if you compared the development of the air airdustry with say that of electronics, but in reality, very little has changed. All aircraft look the same for a very good reason. Using equations and theorems which are all over 50 years old, there is in fact very little room for maneouvre in the design. The only real advancements have come in the realm of avionics and materials which have allowed planes like the Eurofighter to be made, which is an inherently unstable aircraft. The only commercial application of clever tech like that in other airplanes is in the ability to reduce drag by shifting the centre of gravity relative the centre of lift which essentially will reduce the drag of the craft if done correctly. Concorde was (and is) revolutionary because of the absolutely outstanding aerodynamics of it. It uses its planform to generate lift when working out of its optimised regime in a way which no other aircraft does to this day (AFAIK) (clever use of trailing vortices to actually generate lift across the planform at high angles of attack rather than just cause drag). I could go on for hours about the elegance of the design, but i think the best way to summarise it is to look at say the wing of a 777 and notice all the little riblets, all the little aerodynamic tricks which are there to compensate for other features. By comparison, the concorde is a wholly integrated design, every feature working together to create the whole. Design like that is a real tribute to the French (particularly the french since they were in charge of the aero) and British designers which came up with it.
Slashdot Mirror
The P800 has a software option for you to switch off the gsm circuitry (for planes etc) so you don't have to get irradiated...
sorry - for asynchronous read symmetric...
(its been a long day)
Surely this type of service is great in an asynchronous environment, but aren't the vast majority of fat pipes around the world are upload capped? as the number of users increases, surely the sum of the bandwidth downloading will ultimately be limited by the bandwidth uploading - not a problem at the moment as there are a good number of people on t1s etc, but as more and more people use the service, is this not going to become a problem?
In answer to your question: Civil Aircraft navigate using a variety of methods. Depending on where in the flight programme these are, this could be anything from VOR (Very High frequency Omni Directional Range) system to a Heading Select system ILS system or ADF. The Nav system itself functions using a variety of inputs including VOR (Military systems operate on TACAN (Tacital Area Navigation) which uses UHF rather than the mid band frequencies that VOR uses), Compasses, Accelerometers, Gimballs, Gyros as well as Ground Mapping RADAR fixes, GPS (these days), JTIDS (Joint Tactical Information Distribution System -Military again), On-Top fixes, HUD fixes and Offset fixes in addition to ADF (automatic direction finding) These inputs are used for comparison within the autopilot which uses a triplex (usually) voting system to decide what to show and what to do. (obv this various from system to system) So, finally, in response to your question, yes the plane does use a compass to navigate and whilst all these sub-systems are designed to promote redundancies within the larger system, they are taken into account and in the event of a larger systems failure, may be relied upon more than the pilot may realise - hence one of the major problems in over reliance on redundant systems...your perceived level of safety increases thereby causing you to change your actions accordingly and hence reducing the overall safety of the craft. - But thats another story. Incidentally, the reasons for not using cell phones on planes are neatly put at this link Airborne operation of PEDs [PDF] (I am not a pilot)
Is there not the (tiniest) possibility of a spark if you drop the phone and the battery pops off - ? (just a question)
maybe it never had appletalk switched on to access the ethernet port before?
Wait a couple of weeks if you can and get her a 15" AluBook
Looks genuinely useful here is another selection Search Result
ipfw rules sudo ipfw add 08800 deny tcp from any to any portnumber in via en0 for wired connections If i remember correctly... You will have to edit the ipfw file to get it to remember this on startup though... sudo pico /etc/ipfw.conf
PS I don't think this has anything to do with Rendezvous.
In this particular case the problem is appletalk routing. Since you are creating a local subnet using the PowerMac as the router, you probably have appletalk activated on the wrong network interface. It needs to be on the Airport ethernet only and not on the wired connection. It can only be on one at a time so just switch it. - incidentally this won't change your ability to share info with the airported computer. You could also try blocking access to the appletalk port (548 IIRC) on your built in firewall. Alternatively, get a proper hardware firewall and use that to mask your subnet. Ultimately you need to be careful what services you enable on which interface as one of them is visible to the world and one isn't.
Principally you have 2 problems. One is who would buy it, you are transsonic,so you have to fly over desert or ocean so you are limited to certain routes (as you say, but it limits the market dramatically). The other is the fact that the fuel consumption is not associated with the high cruising speed, but the getting to that speed. The difference in economy associated with a lower speed design is in fact not huge. once you are supersonic you are supersonic and its crossing that barrier that poses the problems. the real engineering barrier is above m2.2. thats when you start to get into real trouble requiring new materials and cooler tech.
1. depends on the coefficient of friction. 2. concorde flies at twice the altitude of other aircraft where the air is pretty thin.... 3. besides which there is a lot more to drag than just skin friction...induced drag etc... of course roughly speaking makes all this pretty irrelevant since the olympus engine is a beast.
Of course the engines are another matter altogether...no argument there....
with 30 years advancement in technology.
You would expect there to be a revolutionary new plane out in the skies if you compared the development of the air airdustry with say that of electronics, but in reality, very little has changed.
All aircraft look the same for a very good reason. Using equations and theorems which are all over 50 years old, there is in fact very little room for maneouvre in the design. The only real advancements have come in the realm of avionics and materials which have allowed planes like the Eurofighter to be made, which is an inherently unstable aircraft.
The only commercial application of clever tech like that in other airplanes is in the ability to reduce drag by shifting the centre of gravity relative the centre of lift which essentially will reduce the drag of the craft if done correctly.
Concorde was (and is) revolutionary because of the absolutely outstanding aerodynamics of it. It uses its planform to generate lift when working out of its optimised regime in a way which no other aircraft does to this day (AFAIK) (clever use of trailing vortices to actually generate lift across the planform at high angles of attack rather than just cause drag).
I could go on for hours about the elegance of the design, but i think the best way to summarise it is to look at say the wing of a 777 and notice all the little riblets, all the little aerodynamic tricks which are there to compensate for other features. By comparison, the concorde is a wholly integrated design, every feature working together to create the whole.
Design like that is a real tribute to the French (particularly the french since they were in charge of the aero) and British designers which came up with it.
(yes i am an aero engineer)