Sparse matrices are occasionally encountered during solution of various problems by means of numerical methods. particularly the finite element method. ELLPACK sparse matrix storage scheme. one of the most widely used methods due to its implementation ease. https://www.roneverhart.com/HGST-Ultrastar-7K6000-HUS726040ALS214-4TB-7-2K-RPM-SAS-12Gb-s-512n-128MB-3-5-SE-Hard-Drive/