Definitely. Once I had a coworker, who said, after I had explained the concept to him: "What do you need a spacecraft for? There is Earth! Isn't Earth like a giant spacecraft?"

And he's right: Earth is like a spacecraft too. Or, if you expand on the concept of giant spacecraft, our solar system could entirely be contained in some kind of chamber inside a spacecraft, and what we see as stars, might be other chambers with other solar systems. That's the largest of spacecraft imaginable! ;)

Universes could be like snowflakes falling on a winter day, and galaxies like little ice crystals ... who knows? ;)

And then there might be God who sent us on a journey ... question is: Will we ever know when the journey is over? Is there a goal within our reach? :)

The secret order should be where the AI of the ship comes in. It would have to select the best new members for the order, and keep them "aligned". This would keep management "cost" in that area minimal. Now picture the consequences of your suggestion: Let's assume for a moment that the ship is governed by a democratic government. In the worst case, it would have control over the ship. There'd be various interest groups that would try to gain control of the ship. Would you like to see them die, the billions of people on such a ship? One tiny error in the control of such a ship can cause all people to die. Now put it in the hands of power-hungry madmen. That's why still in democratic governments, there's still shadow groups like secret societies, and secret services that keep some information out of the hands of even the highest ranks in government. To keep a democratic government at bay and in functional condition, the AI would have to use far more sophisticated tactics (if even allowed to do so). Meh ... I like the secret order thing much better. People can go ahead and have their governments and such, but don't mess with the ship! lol ;)

Certainly, you're right. It would be the reasonable choice, to make everything transparent and open ... if it works for a couple hundred or thousand years, that is the question. What if the ship falls into anarchy, civil wars, dictatorships? The ship must still function under those circumstances, and ship its passengers along and nourish them. In a ship with Earth-like conditions, rain would fall and sun would shine, grass would grow, and cows would feed ... mountains and rocks would endure the centuries. People will be born and die, become dust and nourish the trees. I wonder if people would not forget where they are after a couple of centuries ... with all tech happening in the background, they would never even need to be aware of the fact. But who knows? There's a lot of possibilities.

I thought about his pretty often, and I think that the most reasonable form of generation spacecraft would be AI controlled, self-repairing, self-sustaining, and very huge, so that Earth-like landscapes could be built in them. A ship that is 1000 km wide and high, and 10,000 km long would not be much different from a planet to its inhabitants. Clarke's 1x4x9 ratio also would make a reasonable form factor. Such a ship can of course only be built when resources are mined from the solar system planets, especially the gas giants have plenty of matter to utilize. With an "army" of robots, such a thing would be comparably easy to build and to maintain. The ship would have to have automated mining facilities, factories and so on. To the people, it would be like an ordinary world. Many of them would not need to know they're on a spacecraft. But some staff should definitely exist (an order perhaps?) that knows about the journey. Also, the government of the ship could be such that it's clear to everyone they're on a spacecraft, but then provisions need to be in place to avoid mutinies, etc.

Of course, but this was about whether it can be done by a C programmer in less than 1 hour.

However, with this little change, which I completed in less than 5 minutes, the program completes in only 0.056 seconds and makes it only 5 times slower than the tail version. ;)

The setvbuf() in this case has the effect, that the fseek() will fetch a 10 megabyte-sized chunk upon the first read backwards from the end of file. This makes the inefficiency of repeated fseeko() calls for every character almost negligible. :)

With a 1 gigabyte file of random data, my program needs 21 seconds, while the tail version naturally completes within 0.011 seconds, so in this case, it'd be roughly 2000 times slower! :)

But it's proof that a functional equivalent can be written by a C programmer in less than 1 hour! :)

Yup, I know that. S/he wanted me to demonstrate it could be written in less than 1 hour, and that's what I did: I intentionally didn't try to reimplement the UNIX tools, only the essential functionality. So, my code doesn't seek backwards (I do have written code before that does just that), instead I keep line positions in a cycling buffer and scroll through them. Also note the setvbuf() call, which speeds things up by reading 10 megabytes at a time. The getc() call is a macro that expands to code that is executed in the cache of the CPU, so the result will be pretty fast. Granted, I haven't tested it with overly large files, but the performance won't be too shabby. But it certainly won't be as fast as tail.

Ah, I forgot to mention that fseeko() and ftello() are POSIX functions, but needed to process 64 bit files on 32 bit systems (when _FILE_OFFSET_BITS 64 is used).

Well, this code does the same as yours. I wrote it in 46 minutes, using only the ANSI C library.

A skilled C programmer also needs less than 1 hour for something like that. The standard C library has a lot of text processing functions (like sscanf()), plus it has a qsort(). Ever wonder why the C I/O library is suitable for managing database files? All the field functions in fscanf()/fprintf() etc. are suitable for database management.

Also, C is still one of the prime choice languages for writing compilers, which do a lot of text processing.

Inertia Drive.