uint32_t read_len; /* bytes read into buffer, if zero, block empty */
uint32_t VolSessionId; /* */
uint32_t VolSessionTime; /* */
+ uint32_t read_errors; /* block errors (checksum, header, ...) */
int BlockVer; /* block version 1 or 2 */
bool write_failed; /* set if write failed */
bool block_read; /* set when block read */