This is OWFS -- the one-wire filesystem.
OWFS is an easy way to use the powerful 1-wire system of Dallas/Maxim.
A simple and flexible program to monitor and control the physical environment. You can write scripts to read temperature, flash lights, write to an LCD, log and graph, ...
1-Wire is a data protocol stat allows simple connections to clever chips. The chips are uniquely addressed, and have a variety of types, including temperature and voltage sensors, switches, memory and clocks.
What Is 1-Wire Technology?
The basis of 1-Wire® technology is a serial protocol using a single data line plus ground reference for communication. A 1-Wire master initiates and controls the communication with one or more 1-Wire slave devices on the 1-Wire bus (Figure 1). Each 1-Wire slave device has a unique, unalterable, factory-programmed, 64-bit ID (identification number), which serves as device address on the 1-Wire bus. The 8-bit family code, a subset of the 64-bit ID, identifies the device type and functionality. Typically, 1-Wire slave devices operate over the voltage range of 2.8V (min) to 5.25V (max). Most 1-Wire devices have no pin for power supply; they take their energy from the 1-Wire bus (parasitic supply).