The next test will help to evaluate the “scalability” of HDDs firmware according to the workload. Random read comes first.

Here, average access time influences the result most. The IBM/Hitachi is the best, and Samsung SpinPoint PL40 is the third. Unlike the competitors, Samsung’s firmware gives up when the workload increases.

The next diagram shows averaged data for all read/write ratios, except the two terminal cases.

When read and write requests are mixed together, the IBM/Hitachi drive loses its leadership under linear workload. It loses to Samsung PL40 that even defeated its predecessor with a lower access time. I’d better not mention the outsiders: Maxtor and Seagate.

In case of 100% write requests the graphs take quite another look. The drives that feature lazy write functions manage data under low and medium workloads quite well, but starting from 32 outgoing requests it is the operation system that sorts the requests out and determines the overall result.

The shape of the Seagate graph tells that the drive does have lazy write function, but its efficiency is too low. I will try to explore this phenomenon and report to you in one of our future reviews.