TSS/360

The IBM Time Sharing System TSS/360 was an early time-sharing operating system designed exclusively for a special model of the System/360 line of mainframes, the Model 67. Made available on a trial basis to a limited set of customers in 1967, it was never officially released as a supported product by IBM. TSS implemented a number of novel features, some of which eventually saw daylight in more popular systems such as Multics and VM/CMS. Despite its many advances and novel capabilities, the TSS/360 project was a costly and embarrassing failure for IBM.