  In this paper, we present a generic framework for constructing systematic
minimum storage regenerating codes with two parity nodes based on the invariant
subspace technique. Codes constructed in our framework not only contain some
best known codes as special cases, but also include some new codes with key
properties such as the optimal access property and the optimal update property.
In particular, for a given storage capacity of an individual node, one of the
new codes has the largest number of systematic nodes and two of the new codes
have the largest number of systematic nodes with the optimal update property.
