Why buses?
Joined: Dec 2002
Posts: 199
Likes: 0
From: flightdeck/earlyhours commute
I'll give my view based on previous career as ex-engineer, and ome things explained in the grey mists of time from college...
The term bus derives from omnibus. A latin expression or term, Omni, essentially 'for all'. ie Omnipotent, Omnidirectional, etc
Later, the bus (transport) being a bit of a simplification, mainly meaning a carriage for everyone. It was I believe originally refered to as the omnibus.
The term 'bus became commonly used in electrical and electronics meaning essentially the same thing. Presumably, a bus to get something from place to anywhere/everywhere on a route.
Databus- same data for everything that needs it.
Busbars. the same power source for everything that needs it.
A bit over simplified, but I think thats it.
SSD
The term bus derives from omnibus. A latin expression or term, Omni, essentially 'for all'. ie Omnipotent, Omnidirectional, etc
Later, the bus (transport) being a bit of a simplification, mainly meaning a carriage for everyone. It was I believe originally refered to as the omnibus.
The term 'bus became commonly used in electrical and electronics meaning essentially the same thing. Presumably, a bus to get something from place to anywhere/everywhere on a route.
Databus- same data for everything that needs it.
Busbars. the same power source for everything that needs it.
A bit over simplified, but I think thats it.
SSD
Joined: Feb 1999
Posts: 402
Likes: 0
From: land of the long BLUE cloud
Buzz bars is just the common mispronounciation by those who want an electrical association!
Along with the previous explanations, I understood that busses, as in omnibusses, were the original application of this type of power distribution.
Along with the previous explanations, I understood that busses, as in omnibusses, were the original application of this type of power distribution.
Joined: Jul 2007
Posts: 92
Likes: 0
From: Europe
It's a name for a certain (not necessarily electrical) topology.
Assume, you have a host unit and several guest units you want to connect. Then there are 2 main possibilities:
1) Connect every item separately, i. e. with its own cable - this is called star topology. 100 MBit Ethernet is an example, it *needs* a central node (switch).
2) Connect every guest with the very same cables like a daisy chain - this is called bus topology. The central heating in a multi story building is an example, because one riser line serves multiple radiators.
Of course you want to save weight on every aircraft, therefore not every unit has its own connection to battery / generator / whatever, instead the lines are extended from one unit to the next. (Well, since you wouldn't extend from something in the starboard wing directly to the outer portside, this has its limits, but its called "bus" anyway because of simplicity.) In general, most power supply layouts in electric / electronic devices are busses, not only in aviation industry.
Also data connections are sometimes buses. The disadvantage is the protocol overhead you need to tell the connected devices which unit is the addressee of a particular data packet. It can take quite a bit of extra bits and electronics in order to sort these things out. Also redundancy suffers when the cable is cut somewhere, because all units are affected at once. But obviously you can take care about these things - A380 is doing a major part of its communication via special Ethernet derivative.
If you are interested further, Wikipedia tells a bit more when you search for "star network" or "bus network". (This is where I got the images from.)
Assume, you have a host unit and several guest units you want to connect. Then there are 2 main possibilities:
1) Connect every item separately, i. e. with its own cable - this is called star topology. 100 MBit Ethernet is an example, it *needs* a central node (switch).
2) Connect every guest with the very same cables like a daisy chain - this is called bus topology. The central heating in a multi story building is an example, because one riser line serves multiple radiators.
Of course you want to save weight on every aircraft, therefore not every unit has its own connection to battery / generator / whatever, instead the lines are extended from one unit to the next. (Well, since you wouldn't extend from something in the starboard wing directly to the outer portside, this has its limits, but its called "bus" anyway because of simplicity.) In general, most power supply layouts in electric / electronic devices are busses, not only in aviation industry.
Also data connections are sometimes buses. The disadvantage is the protocol overhead you need to tell the connected devices which unit is the addressee of a particular data packet. It can take quite a bit of extra bits and electronics in order to sort these things out. Also redundancy suffers when the cable is cut somewhere, because all units are affected at once. But obviously you can take care about these things - A380 is doing a major part of its communication via special Ethernet derivative.
If you are interested further, Wikipedia tells a bit more when you search for "star network" or "bus network". (This is where I got the images from.)
Joined: Feb 2001
Posts: 6,729
Likes: 104
From: The Winchester
Shiney Side down
I reckon you are right and if you look hard enough most of the other explanations here actually go back to the latin "omnibus", or "for all" origin... road buses, Databuses, or whatever, they are all common carrier,i.e. "for all".
Right, lesson over, now as my dear old Latin teacher would have said "write it out a hundred times before dawn or I'll cut your ****** off"..( or was it John Cleese?)
Right, lesson over, now as my dear old Latin teacher would have said "write it out a hundred times before dawn or I'll cut your ****** off"..( or was it John Cleese?)
