Hard drive capacity is essentially not an issue anymore since capacity is cheap and easily expandable. Hard disk speed is of great importance when it comes to disk-intensive operations like storing data. This applies to all forms whether logging into a database or to proprietary datalog files. Hard disks with low rotational speeds (5400rpm) are not recommended in general as their read and write performance typically hinders the overall performance of the system especially when it comes to historical data storage and retrieval