[NCjim]

The System/360 was introduced April 7, 1964. They were called third-generation machines - the first true multi-tasking machines.

[StopGlobalWhining]

...the first true multi-tasking machines.

The 360 was the first machine with a combination instruction set that included characters (eg MVC), packed decimal (eg ZAP), integer arithmetic (AR), and floating point arithmetic (AWR).

I think GE's GECOS was the first generally available multi-tasking (time-sharing) operating system, but on that point I may be mistaken. It might have been UNICOS (UNIVAC 1108).

[wideminded]

The System/360 was introduced April 7, 1964.

A long time ago I worked for a brilliant guy who had been involved in the design of the 360. He told us that the pressure was so intense to get the 360 out that two people committed suicide.