Yes. I would say, first of all, the change quarter-over-quarter is mainly coming from mix. If you look at the hard disk drive gross margin, is completely flat to the prior quarter. So we don't have any change in profitability for the hard disk. We have increased a lot our non-hard disk revenue, mainly in the SSD part of the business, and that is driving some reduction in the overall gross margin. But of course, it was also very helpful at the revenue level and the free cash flow level.
Now when you look inside the hard disk, mass capacity was at a record high, fairly close to September as we were expecting about 1% higher, but still a good record high. Legacy was sequentially down in mission-critical, but as you know, is a high gross margin segment. And was actually higher in consumer that is actually a lower gross margin segment. So there is a lot of mix going on into December. But finally, the reality is hard disk in total, was flat gross margin compared to September and the increase in the non-hard disk part was driving the slight decline at the company level.
Now when you go into the March quarter, where it's still a mix impact, it's a different kind of mix. This is more a seasonality impact. Some of the segments that will be seasonally low are fairly high gross margins like surveillance, like mission-critical. Other segments are actually fairly, let's say, not low but low at gross margin like consumer. And we also expect at this point, some decline in the SSD part of the revenue.
So when you put all together, again, the mix is probably driving the gross margin in the March quarter, slightly down from the December quarter, but it's not coming from the business. It's coming mainly from the mix. As Dave was saying before, of course, we have also some cost increases, mainly in the freight and logistic cost. We thought 2 quarters ago to be at already the high level of the freight cost, but it continued to increase in September and again in December. This we expect to start declining in the next few months. But with our spending control, with the strong mass capacity business that we have, we have mainly offset those bad news coming from the cost leaving the mix impact, of course, impacting the total result.