A number of low-cost hard disk recorders are also available.
Here is one of the most useful ones.
The following products come with a monitor and the internal hard disk can be replaced with a commercially available size.
Long time recording of up to 2 months is possible.
It has four video (NTSC) input terminals.
If a PC is available without such a device, a USB or GigE camera and
long-time recording software can be used to record long videos.
Industrial USB Cameras
Industrial GigE Camera
Long-time recording software for industrial USB cameras and GigE cameras