Fd Object

object_fd

This is the flash disk (fd.) object, it allows you to use your device's flash memory for data storage. There are two methods of working with the flash memory:

  • With direct sector access, you can write and read flash sectors directly, without burdening yourself with the file system.
  • With file-based access, you create a formatted disk that stores files.

Both methods can be used concurrently and complement each other whenever necessary.

Here is what the fd. object has to offer in terms of the file-based access:

  • Ability to store up to 64 files located in a single root directory (subdirectories are not supported, but can be emulated).
  • Flexible file attributes — define and store any attributes you like.
  • Methods to work with the file directory.
  • Ability to open and work with several files at once.
  • Methods to write to and read from the file, also cut out a portion of the file from the beginning or end.
  • Fast and flexible search to locate data within files. This also includes a record-style search!
  • Automatic sector leveling.
  • Transactions to ensure disk integrity in the toughest of conditions (power failures, etc).
  • A method for firmware/application self-upgrades (not supported by all platforms).

note_warning-wtOn the advice of one of our customers we are giving you the following reminder: Like all other flash memory devices on the market, flash ICs used in Tibbo products only allow for a limited number of write cycles. As the Wikipedia article on flash memory (https://en.wikipedia.org/wiki/Flash_memory) explains, modern flash ICs still suffer from comparatively low write endurance. In Tibbo devices, this endurance is around 100'000 write cycles per sector. When you are using the flash memory for file storage, the fd. object employs sector wear leveling to maximize the life of the flash IC (but the life still remains limited). If your application employs direct sector access, then it is your job to plan the application around the life limitations of the flash memory. For data that changes often, consider using the EEPROM memory accessible through the stor. object. EEPROMs have much better endurance.