Even those implement communication primitives e.g. locks, semaphores, mailboxes, etc. as part of the OS. Some of the larger ones also define a driver model of s

Even those implement communication primitives e.g. locks, semaphores, mailboxes, etc. as part of the OS. Some of the larger ones also define a driver model of sorts (which often just codifies the structure of the first driver for that type of peripheral e.g. USB, Ethernet, CAN, I2C, SPI, GPIO).