Another question is, what's the difference between SysFile.lib and SysLibFileAsync.lib?
looking into the documentation area of SysFileAsync you can read, that this library is a "wrapper" for SysFile to handle asynchronous access to file functions. That means, the requested function will be processed in the background, and in your program you have to wait for the result. This may last some time, depending on the function and your hardware etc.
The big advantage is that your application program is not interrupted by a slow file access, which might cause trouble in your machine.