"Most processors from the 386 on have easily handled that many threads. What I think the author means when he says 'thread' is actually 'process'"

When you look at traditional processors, every time a new "process" needs to be swapped in, the CPU must push the registers back to memory.

Some CPU Architectures will switch between "threads" of execution without pushing all of the registers out to slow memory and the same memory segments are often leveraged by the thread of execution.

When you look at SPARC processors, registers do not necessarily have to be pushed out to slow cache during a process switch, meaning SPARC scales better with multiple processes than traditional CPU's.

When you look at the T1 & T2 processors, the CPU is not pushing registers out to slow memory, and the hardware threads can operate on different memory segments simultaneously without pushing program execution address registers out to slow memory.

To understand why SPARC and CoolThread T1 & T2 scale to hundreds of simultaneous threads more efficiently than traditional processors and millions of processes effectively when traditional processors will merely thrash with their applications timing out - one must understand architecture.

SPARC allows for much heavier utilization than traditional processors while SPARC CoolThreads allow for massive utilization over traditional processors - all because of threading.

This does not mean that SPARC is perfect for every bill - but one must be educated to understand when it does fit best.