AFAICS, that author of that article is misinformed.
AIUI, the drive only skips over bad blocks when its Streaming Command
Set is enabled. The drive still supports the regular command set. In
fact, these commands *must* be used whenever the file system is
updated. The user of an AV-GP drive may not care about a dropped video
frame, but he must have confidence that his file system is intact.
Furthermore, a drive that supports TLER (Time Limited Error Recovery)
is to be preferred over non-TLER capable drives in RAID environments.
A drive that takes too long to recover from an error may drop out of a
RAID.
FWIW, here is an excerpt from a Seagate technology paper:
Seagate Briefing: Optimizing Surveillance DVR Reliability:
http://www.axetech.be/Pdf/Accessoires/HD/Seagate Technology Paper _SV35 QandA.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."
Section 4.3 of the following document lists the supported ATA commands
for Seagate's video surveillance models.
SV35 Series SATA Product Manual, Rev. D:
http://www.seagate.com/staticfiles/support/disc/manuals/ce/SV35 Series/SV35.5 Series/100562053d.pdf
These ATA commands include the following:
Read DMA (C8h)
Read DMA Without Retries (C9h)
Read Sectors (20h)
Read Sectors Without Retries (21h)
Read Verify Sectors (40h)
Read Verify Sectors Without Retries (41h)
Write DMA (CAh)
Write DMA Without Retries (CBh)
Write Sectors (30h)
Write Sectors Without Retries (31h)
- Franc Zabkar
)