Serial ATA

The main advantages over the older parallel ATA interface are faster data transfer, ability to remove or add devices while operating (hot swapping), thinner cables that let air cooling work more efficiently, and more reliable operation with tighter data integrity checks.

It was designed as a successor to the Advanced Technology Attachment standard (ATA), and is expected to eventually replace the older technology (retroactively renamed Parallel ATA or PATA). Serial ATA adapters and devices communicate over a high-speed serial cable.

For the last few years the SATA connection has been making it’s way to the high speed DVD recorders, as it has become also the main stream method for connecting hard drives, and is a standard feature on every computers motherboard these days. In optical recorder drives the legacy PATA connection has sustained it’s position surprisingly well. This will change in the next generation though, as Blu-ray drives need the higher bandwith provided by Serial ATA.

In this article we are using two recent drives by Pioneer Electronics. The Pioneer DVR-215 is a SATA drive, while the Pioneer DVR-115D is connected using the good old PATA. Besides the connection method, the only difference of these drives is that the Pioneers D-models do not support the DVD-RAM format discs.

Hardware installation

Our hardware setup for this test was a bit challenging. Our test bench computer has an onboard Intel SATA controller, but it was reserved by the RAID hard drives. Even though we had read and heard about people’s poor experiences of using a PCI SATA controller card with a SATA recorder, we decided to give it a go. Our efforts failed in this matter, and after various different PCI controllers (one of the was a totally wrong model, and our own mistake) we gave up on the idea. We started with a cheap Silicon Image 3112 chip based card, which was supposed to work with Pioneer and Plextor drives, but the system refused to boot with this configuration. With a Promise based card we got the system up and running, but the drive was not detected properly, and the system was stalling constantly. With these attempts failing we were forced to use the onboard Intel controller. The drive was immediately detected and working as expected so we could begin benchmarking.

The performance of SATA vs. PATA

First we performed a recording test, by using a number 16x speed Datawrite (CMC Magnetics) media that these drives are able to burn at 18x speed. The image on the left is the Pioneer DVR-215 and on the right is the 115D. Click on the images to have a closer look.

Couple of observations can be made from the graphs above. While the SATA connected drive seems to produce a bit higher average CPU load (2%), the device recording buffer is constantly at 100%. The PATA connected drive produces less CPU load, but the buffer level is constantly decreasing as the data rate accelerating towards the end of the disc. The recording speed of these two drives was identical (media can cause slight variance in between discs). Next step was to try the read performance. Once again 215 on the left and 115D on the right.

All the measured performance features produced identical results. We repeated these tests a number of times to cancel out any disturbances that might be produced by the test environment, and the results remained equal from test cycle after another. There was one exception though – the burst transfer speed of the SATA connected 215 model was constantly about 10MB/s higher. Next we decided to try the recording again, this time by recording a real image file from the RAID hard drive, which was now connected to a PCI SATA RAID card instead of the motherboard. 215 on the left, 115D on the right. Click on the images to have a closer look.

The real life recording test by using ImgBurn confirm what was already shown in the first graphs. The buffer of the SATA connected drive remains at 100% (screenshots are from the 95% recording point), while the PATA connected 115D is bouncing around 80% at this point.

Conclusion

First of all I must conclude that the Pioneer DVR-215 is an equally great drive than the 115D, with the possible benefits of the Serial ATA connection. The performance test showed that there is measurable difference in the connection method, but in these test cases they did not result in real-life differences in recording or read performance. However in some conditions the SATA connected drive could potentially give a smoother ride, thanks to it’s ability maintain the device recording buffer at 100%.

Which one to choose then, if one has both options available? I think the answer depends on the PC hardware. If I was building a new system with on-board SATA, I would choose the SATA connected 215 model. If one has an older PC, like our test bench, the SATA is an interesting option but the possible compatibility issues with the SATA controller must be understood first. However, under no circumstances I can recommend a SATA drive in combination with a PCI SATA controller card – it may work for some, but it has also failed for many and your mileage may vary. The SATA connection doesn’t seem to give that significant benefits that it would be worth buying a separate controller for the job.