L3 Communications Targa 4 Series, Technical Reference And Installation Manual

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TARGA SYSTEMS
S4 SATA & USB DTU Installation Guide 32003444 Rev A
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3.6 DTD Startup
At startup, the DTD SATA Flash disk must mount/initialize the FLASH memory array
before media requests can be processed. The worst case delay can be 5 seconds for large
capacity drives, but the typical delay is approx 3 seconds.
Note: For the SATA DTU, the DTD must be installed during the host boot process to
ensure that the operating system recognizes the removable drive and assigns a
drive letter.
3.7 Data Reliability
The DTD provides enhanced data reliability via the following mechanisms;
·
All erase/write operations are performed in a closed loop operation to verify data has
been erased and programmed correctly with the proper voltage margins.
· Data is checked with a powerful Error Correction Code (ECC) that offers a high
degree of data protection.
· Built in defect management with automatically sector reassignment based on
detected memory errors.
3.8 DTU Startup/Shutdown
The DTU door mechanism is designed with an optical sensor, upon detection of a door
opening, the DTU will remove power from the DTD before it can be removed.
- WARNING -
This controlled power down sequence cannot prevent data loss or file structure
discontinuities if the DTD is removed while writes to the DTD are in progress, or if data is
still held in the Host system cache memory. An operator initiated ‘eject’ or ‘file close’
operation should always be done prior to removing the DTD to ensure that all the host
system cached data and file structures have been written to the DTD before it is removed.
Many operating systems provide a “Safe to Remove” prompt when all of the relevant data
has been written to the removable disk .
3.9 Hardware Erase
This is an embedded function within the FLASH disks used in the DTD. The disks have
been configured to perform a “Hhigh Speed Clear” followed by an “initialization” to
prepare the FLASH array for subsequent use. In the event of a power failure during this
process, the SATA disk will automatically resume this process, before it can be accessed .
Upon completion all FLASH memory contents will have been erased and the DTD will
have to have the associated Host file system structures re-written to it before it can be
used.