User manual

3.5 SD Card Recording
3.5.1 Introduction
Flash-based storage devices (SD cards, CF cards, USB sticks and solid-state disks)
do not contain any moving parts as compared to the commonly used hard disks.
Flash-based devices are compact, largely resistant to humidity and shock, use very
little energy, do not loose data on power failures and get less expensive all the
time. They are thus ideally suited for the MOBOTIX cameras.
Maximum Data Transfer Rate
Using high-quality Flash devices such as the MOBOTIX R models will allow record-
ing the video sequences of a MOBOTIX camera with the highest possible frame
rate (e.g. continuous recording including audio). When using SD cards, however, it
is imperative to use a high-quality card with a high maximum data transfer rate
(writing speed is most important). For information on recommended SD cards,
please see the MOBOTIX website www.mobotix.com.
Number of Write/Delete Cycles per Flash Storage Cell
The number of write/delete cycles of every storage cell of a Flash device is limited
(e.g. 10,000, 100,000 or more, depending on the quality). The controller of the Flash
device automatically detects Flash cells that do not work properly any more. The
contents of the faulty cell will then be rebuilt using a checksum and will be moved
to a properly working spare cell. The faulty storage cell will be marked as "bad"
and will not be used any more. Note that no data is lost in this process.
In addition, MOBOTIX cameras constantly monitor the wear of activated Flash stor-
age devices. MOBOTIX has developed a technology to test the wear of the Flash
device by logging the number of write/delete cycles (patent pending). Open Admin
Menu> Camera Status to see the Flash Cell Wear parameter. The camera can
also display this information in the status bar at the bottom of the live image.
Conservative Memory Usage Thanks to MOBOTIX MxFFS File System
MxFFS formatting of the SD card means that the MOBOTIX camera software will
use the Flash device as evenly as possible, thus allowing for the maximum possible
number of write/delete cycles. This also means that all storage cells of the Flash
device will be written and deleted with the same frequency, if possible. The
MOBOTIX technology increases the life of the Flash device considerably and also
improves the security and the reliability of the storage process.
© MOBOTIX AG • Security-Vision-Systems • Made in Germany
www.mobotix.com • [e-mail]
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D12 Camera Manual Part 1