In this paper we reviewed the latest development and discussed several problems in current research on brain-computer-interfaces (BCIs), such as overestimating the function of the human brain and lacking understanding on the way the brain stores information. Based on the model of "2D code" data form for brain functions, we argued that current BCI technical solutions are only applicable to some simple application scenarios, such as understanding the emotional type of the subject, the state of life activities, and controlling the external instruments, but they are not capable to obtain accurate details such as memory and thinking in the brain. On the other hand, we believed that here is a large space for the development of information input technologies, i.e., the information input technology. For example, a potential brain stimulation device with multiple regulatory effects and multiple control methods like physical and biochemical technologies may be widely used to treat brain diseases, such as depression and epilepsy, as well as for short-term enhancement of brain power. This work may shed some light on the current research field of brain-computer interface.