Because the IBM PC was an IBM product with the IBM badge, personal computers became respectable. It became easier for a business to justify buying a microcomputer than it had been even a year or two before, and easiest of all to justify buying the IBM Personal Computer. Since the PC architecture was well documented in IBM's manuals, and PC DOS was designed to be similar to earlier CP/M operating system, the PC soon had thousands of different third-party add-in cards and software packages available. This made the PC the preferred option for many, since the PC supported the hardware and software they needed.