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D24M User Manual: OPERATING THE CAMERA

www.mobotix.com • [email protected]

3.5 MicroSD Card Recording

3.5.1 Introduction

Flash-based storage devices (MicroSD 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,

extremely resistant to humidity and shock, use very little energy, do

not lose data during power failures and are becoming less expen-

sive. They are thus ideally suited for use with MOBOTIX cameras.

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 individual Flash cells that are no longer functioning.

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 no

longer be used. No data is lost in this process.

In addition, MOBOTIX cameras constantly monitor activated Flash storage devices. MOBOTIX

has developed a technology to test the wear of the Flash device by logging the number of

write/delete cycles (patent pending). The Flash memory wear is automatically displayed in

the status bar in the live camera image but it can also be viewed at anytime in the Admin

Menu> Camera Status dialog.

Conservative Memory Usage Thanks To MOBOTIX MxFFS File System

MxFFS formatting of the MicroSD 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.

Storage Requirements And Life Expectancy Of MicroSD Cards

The life expectancy of a MicroSD card increases proportionally to the storage capacity,

since the camera software will execute fewer write/delete cycles on each storage cell.

The ﬁrst deletion will begins once the SD card has been ﬁlled to capacity (ﬁrst full cycle).

The theoretical life expectancy of a 16GB MicroSD card is between 10 and 35 years,

depending on the degree of use.

Flash memory devices:

More reliable than

hard disks.

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