[exim] quota() in cyrus:imap:admin and lq in cyradmin

Hi,

I don't know how to use the quota() function from the Cyrus::imap:admin
module.
The result returned from the quota() function is different from running
lq command in cyradm.
Please see below for illustration.

In cyradm:

> lq user/bob@???
STORAGE 0/512000 (0%)

Cyrus::IMAP:Admin:

my %quota;
my $e;
my $r;
my $mailbox = 'user/bob@???';
($e, %quota, $r) = $cyrus->quota($mailbox);
print "E: ".$e."\n";
print "%quota: ".%quota."\n";

The output of runing the above perl is:
E: STORAGE
%quota: 1/8

I feel confused with this value from the quota() function. What is 1/8
stands for? how come it's not 0/512000 ?

Thanks
Sam