Was it a mistake? It is easy to say that IBM had monopolistic tendencies, because they did. On the other hand, the 5100 sounds like a vertically integrated des

Was it a mistake? It is easy to say that IBM had monopolistic tendencies, because they did. On the other hand, the 5100 sounds like a vertically integrated design and it ended up being extremely expensive. The Datamaster strayed away from IBM components, but was still based upon IBM software. One can blame it's failure on the IBM PC being released a month later, but in a way that would prove the point. The Datamaster had such a big head start that the IBM PC borrowed elements of it's design, while the proprietary software of the Datamaster held back its release date. Undoubtedly, IBM wanted more control over the PC. Avoiding a completely proprietary design was probably a calculated bet, an intentional course of action rather than a mistake. It just happens to be a bet they lost.