Häufig gestellte Fragen
EMTEC product test protocol
Hardware used for the test
- One PC ( Processor Intel i5 or equivalent, 4 GB RAM, USB 3.1 Gen2 Port )
- Cardreader UHS-II (up to 312 MB/s) /USB 3.1
Software used for the test
[ a ] Plug the Flash drive or memory Card on the PC
[ b ] Close all application in Windows
[ c ] Launch CrystalDiskMark 6, Seting :
- Test count : 1
- Test Size : - 100 MB for USB 2.0
- 1 GB for USB 3.1 and SD/MicroSD card
- Test drive
[ d ] Click on "Seq QT32T1" for run the test
USB Flash Drives, formatting and capacity + reliability
There can be several reasons to launch a formatting operation on your USB Drive:
- Erase the data it contained in order to start again on clean bases.
- Change the file system: when you want to make the drive compatible for different OS.
- Change the partitioning : when you want to reorganize your file system and create one or more partitions.
- Presence of viruses: If your drive is severely affected by a malware attack, it is sometimes impossible to install an antivirus or perform a scan to eliminate the threat.
Formatting also is used to perform below tasks: - Testing each memory cell in the Flash storage device.
- Identifying all defective cells and taking steps to ensure that no data will be written to or read from a defective cell.
- Reserving some cells to serve as “spares.” Flash memory cells have a long but finite lifetime. Therefore, some cells are held in reserve to replace any memory cells that may fail over time.
- Creating a File Allocation Table (FAT) or other directory. The file management system must be created to allow any device or computer to identify the files stored in the Flash storage device.
- Reserving some cells for use by the Flash storage device’s controller, e.g., for storing firmware updates and other controller-specific information.
- Where applicable, reserving some cells for special features. For example, the specification for Secure Digital (SD) cards requires reserved areas to support special copy protection and security features.
- A portion of memory space in your external storage is reserved for system files, data sectors, and "spare cells" to ensure the drive performance. This is the primary reason behind the less usable space.
- Another root cause is the calculation method:
Our computers work on base 2 (binary) number system rather than the decimal system. One megabyte of the product you are using is equal to 1,000,000 bytes in decimal base, but for a computer it is 1,048,576 bytes in binary base.
So for each gigabyte advertised in base 10, you're actually receiving about 70 megabytes less than a gigabyte in base 2. This is the reason why the memory displayed in our computers appears to be less than what is actually announced by the manufacturers.
- Also, different operating systems treat your disk differently. Windows OS may not show the disk space like Linux, Mac or Unix. There are little discrepancies between the file formats and algorithms used by different operating systems.
3. Reliability and performance
Before writing the data to its memory, the USB key performs operations to optimize its performance:
- Test the data to be saved in memory. If the data contains errors, they are corrected by the ECC system (Error Correction Code).
- Test of each memory cell of the USB key. Identify all defective cells and take steps to ensure that no data is written to or read from a defective cell.
- Reserve some cells to serve as spare parts. Flash memory cells have a long but limited lifespan. As a result, some cells are kept in reserve to replace memory cells that may fail over time.
- To limit the premature wear of some memory cells, the USB key always selects the least used cells for recording data (Static and dynamic wear leveling system)
What number of files to be stored by capacity
|4 GB||8 GB||16 GB||32 GB||64 GB||128 GB||256 GB|
|Photo APN 12 Mpixels (3,6 MB)||1000||2000||4000||8000||16000||32000||64000|
|Music MP3 (3,5 MB)||1050||2100||4200||8400||16800||33600||67200|
When I plug my flash drive to the USB port, nothing happens
Check that the USB port is not defective.
If you have multiple devices connected, it can happen that your USB port does not deliver enough power to the flash drive, in that case, try using a USB HUB having external power supply.