What's the special for video surveillance drives?

[bigspace]

Currently I find there are several models of video surveillance drives in market. In my understanding, it's optimized for video applications. It can run for 24*7 hours every week, so it's better than desktop drives. But the performance is worse than enterprise drives. Am I correct?

The price of video surveillance drives is less than the price of enterprise drives. But in datasheet I find the read/write rate of VS drives is still fast. What's the real difference between them?

[fzabkar]

The AV drives support the ATA Streaming feature set.

Seagate Briefing: Optimizing Surveillance DVR Reliability:
http://www.axetech.be/Pdf/Accessoires/H ... er%20_SV35%0QandA.pdf

"Perhaps surprisingly, complete data integrity for video is not vitally important. That's because a small error introduced into a video stream doesn't compromise the overall integrity of the visual image. While a small, perhaps imperceptible, flaw may occur, the overall video is still intact. However, in order to manage the vast amounts of video and related metadata in a surveillance system, a keyed relational database or similar traditional data organizational system is often used. It is absolutely critical that reads and writes for such systems employ the utmost levels of error correction and detection to ensure data integrity isn't compromised.

An important feature of the SV35 Series disc drive is its support of the ATA-7 streaming command set. ATA-7 is a recent extension of the industry-standard ATA command set for controlling disc drives. The streaming component of this standard enables the SV35 Series drive's reads and writes to be customized for either video or data payloads. Using the ATA-7 streaming commands, both of these requirements are elegantly met."

[fzabkar]

See http://nevar.pl/pliki/ATA8-ACS-3.pdf

It describes the various streaming commands, eg READ STREAM EXT, READ STREAM DMA EXT, WRITE STREAM EXT, WRITE STREAM DMA EXT.

[bigspace]

Thanks for you explanation. In my understanding, the software should support the feature, otherwise the streaming command won't be used. If I use it on normal desktop PC, then I won't benefit anything from it. Am I correct?

From the spec, the ATA streaming commands doesn't guarantee the data integrity. I am not very clear with this sentence:

The streaming component of this standard enables the SV35 Series drive's reads and writes to be customized for either video or data payloads. Using the ATA-7 streaming commands, both of these requirements are elegantly met.

It seems to tell us that there won't be data integrity problem. How does it solve it? Use different configuration for video and normal data?

Thanks!

The AV drives support the ATA Streaming feature set.

Seagate Briefing: Optimizing Surveillance DVR Reliability:
http://www.axetech.be/Pdf/Accessoires/H ... er%20_SV35%0QandA.pdf

"Perhaps surprisingly, complete data integrity for video is not vitally important. That's because a small error introduced into a video stream doesn't compromise the overall integrity of the visual image. While a small, perhaps imperceptible, flaw may occur, the overall video is still intact. However, in order to manage the vast amounts of video and related metadata in a surveillance system, a keyed relational database or similar traditional data organizational system is often used. It is absolutely critical that reads and writes for such systems employ the utmost levels of error correction and detection to ensure data integrity isn't compromised.

An important feature of the SV35 Series disc drive is its support of the ATA-7 streaming command set. ATA-7 is a recent extension of the industry-standard ATA command set for controlling disc drives. The streaming component of this standard enables the SV35 Series drive's reads and writes to be customized for either video or data payloads. Using the ATA-7 streaming commands, both of these requirements are elegantly met."

[fzabkar]

See section 7.33 of the ATA standard. It explains in detail how errors are handled in streamed data.

http://nevar.pl/pliki/ATA8-ACS-3.pdf