Howitt Ignores IBM System

Matt Howitt is correct ("Tech Talk," Apr. 26) in noting that preemptive multitasking "has existed for a long time," but he omits mentioning IBM's Time Sharing System (TSS) Model 360/67, which used a multitask environment, and paging of memory to create virtual memory. It too was created in the 1960s.

I was one of two people that got TSS up and running in 1966-67. Unlike Windows 3.1, TSS time slice appropriations were under the control of the system operator, through the supervisor (resident program in core memory). The reason was the same then as now; people exaggerate the priority of their applications. Roy Bercaw   Cambridge, MA