Arguments have favoured data tape as a backup medium for hard disks, including low cost, high capacity and robustness. But ultimately performance is limited by the complex mechanical systems, sequential access to the data and the need to share a limited number of reading and writing decks. ALTO offers the same benefits and support established workflows, but with further benefits.

Hard disk drives offer the advantage that each disk is inherently a self-contained reading and writing device capable of random-access rather the sequential access of data tape. The next generation sub-nearline drives used in ALTO are designed to be spun down and switched off when not reading or writing, reducing power consumption and extending disk life, but new techniques are needed to protect the media from disk failure.

Following a disk failure, the lengthy rebuild time for a simple RAID array can leave content vulnerable to subsequent disk failures. Alternative protection strategies significantly increase capital and running cost. ALTO uses data replication techniques to offering user selectable protection, minimal recovery time, and disaster recovery configurations. ALTO disks can be removed for vault storage, or project transport. Media files can be accessed on an external computer.