[BC] ftp sites

[Cowboy]

On Friday 15 September 2006 03:12 pm, Harold Hallikainen wrote:

> Don't FTP sites usually have some sort of limit on the number of
> simultaneous users?

 If properly configured, yes.

> If so, a "slow" streaming playback would keep a user 
> using the ftp connection for longer than one using a quick download.

 No.
 The connections are dynamicly queued.
 My FTP server is set at 4 connections. That means that it will serve
 four streams simultaneously, but will queue however many requests
 there are.
 When one of the active four blocks ( buffer full ) that connection is pushed
 onto the queue, and the next connection on the queue is served, until one
 of the active four blocks for whatever reason.
 This swapping continues until a transfer is completed, then that connection
 is deleted from the queue.

 It's not a windows-ish time slice "fairness" thing.
 It's much more a real time thing. Run the current thread until it either
 completes or blocks, then run the next thread until IT either completes
 or blocks, subject to a higher priority interrupt, in which case the current
 thread is blocked until the higher priority process either completes or
 blocks, then fall back to the scheduler.

 When a buffer fills, that stream blocks. When the buffer becomes unfull, that
 stream CAN run again, but it won't until its turn in the queue, which might be
 immediately, or it might be some time later. There is no deterministic deadline,
 so it's not real time, as a lost or dead connection can be re-established at some
 unknown time in the future and resumed.

-- 
Cowboy