why mirrors ?

[Gustavo Niemeyer]

> What does smart do with any multiple "indexes" it downloaded
> (in a single 'update') from more than one mirror ?   Does it
> 'merge' these "indexes" to create a master list of all packages
> available for downloading ?   And when smart closes, is it this
> master list, or the "index" from the *primary*, that is cached
> for use with a subsequent independently invoked 'upgrade' ?

As Pascal explained, there's a file that tells Smart what
checksums it should expect in other files in the repository.
If other files do not match the expected checksum, they're
simply discarded, and another mirror is tried.

In these situations, some information is recorded to reduce
the priority of mirrors containing out-of-date information.

-- 
Gustavo Niemeyer
http://niemeyer.net