You can use Tie::File to store your data in a file, and use push and shift per Ratazong's suggestion on the array which modifies the file live-time:

use Tie::File;
tie my @file, 'Tie::File', 'file.txt' or die $!;
shift @file if @file == 8;
...
push @file, 'new data';
...
untie @file;
[download]

Then, use cron to run your script every hour, and for any other external processing, just pull the data out of the 'file.txt' file.

-stevieb