The DECtape Library System was a DECtape oriented save and restore system that was available from the start. The resident portion of this system occupies only 17 words of memory (7600-7625 octal), and it allowed saving and restoring absolute core images as named files on a reel of DECtape.

Initially, program development was still done with paper tape, and only executable memory images were stored on DECtape, but eventually, a limited DECtape-based text editor was introduced, along with a DECtape based assembler.

(Source: PDP8 FAQ)