I remember reading about a classroom computer lab where each student sits before his or her own computer to work. Each of the student computers is networked to the teacher's desktop computer where the teacher is able to capture the screen of any student computer to monitor work. Such systems are expensive. They cost tens of thousands of dollars per classroom. I would imagine that they are prone to malfunctions and planned obsolescence.
Computer labs like that seem a costly and poor way to do this sort of work. A much simpler—and more earth-friendly—technology has been around far longer than I have: chalkboards.
Here, see for yourself how a teacher can monitor kindergarteners spelling:
An added benefit is that wood-framed slate chalkboards are very satisfying to use. They're solid and heavy. The chalk is fun to write with, and being short, can only be held with the proper three-fingered grip. The little scraps of bath towels make good erasers. And, done on the mat like this, if someone needs a little help it's only inches away.