What OS does CD-i use?
The operating system used in a CD-i player is called CD-RTOS, which stands for Compact Disc Real-Time Operating System. It is hard coded in a ROM of at least 512 KB, along with other player-specific software such as the player’s startup shell. CD-RTOS is based on version 2.4 of Microware’s OS-9/68K operating system. OS-9 is very similar to Unix, and supports full multitasking and multi-user operation. The original OS-9 was build in the early 80s as a realtime operating system to be used in industrial and embedded applications were real time functionality is a key criteria, such as with robotics, automobile production and set-top boxes. It was slightly adapted to CD-i, for example by including the correct device descriptors for the CD drive, and with drivers for CD-i’s specific audio and video decoding ICs. Since OS-9 is a modular operating system with a very small kernel of only about 25 KB, only the parts used by a specific CD-i player have to be preset in ROM. For example, a CD-i pla
