Please look at the names of the following three monitoring devices. What's the specific use?

The first picture is called a picture divider, which divides the picture on the display screen into 4/6 pictures.

The second one is called hard disk video recorder, which is the monitoring host. The core of the monitoring system is the brain.

The third is the video distributor, which can divide a video picture into two output paths, one is connected to the matrix or monitor, and the other is connected to the hard disk video recorder, as shown in Figure 2.