  Suppose that $\mathscr{E}$ and $\mathscr{F}$ are Hilbert $C^*$-modules. We
present a power-norm
$\left(\left\|\cdot\right\|^{\mathscr{E}}_n:n\in\mathbb{N}\right)$ based on
$\mathscr{E}$ and obtain some of its fundamental properties. We introduce a new
definition of the absolutely $(2,2)$-summing operators from $\mathscr{E}$ to
$\mathscr{F}$, and denote the set of such operators by
$\tilde{\Pi}_2(\mathscr{E},\mathscr{F})$ with the convention
$\tilde{\Pi}_2(\mathscr{E})=\tilde{\Pi}_2(\mathscr{E},\mathscr{E})$. It is
known that the class of all Hilbert--Schmidt operators on a Hilbert space
$\mathscr{H}$ is the same as the space $\tilde{\Pi}_2(\mathscr{H})$. We show
that the class of Hilbert--Schmidt operators introduced by Frank and Larson
coincides with the space $\tilde{\Pi}_2(\mathscr{E})$ for a countably generated
Hilbert $C^*$-module $\mathscr{E}$ over a unital commutative $C^*$-algebra.
These results motivate us to investigate the properties of the space
$\tilde{\Pi}_2(\mathscr{E},\mathscr{F})$.
