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Politics : Formerly About Advanced Micro Devices -- Ignore unavailable to you. Want to Upgrade?

To: Bill Jackson who wrote (28073)	1/22/1998 10:09:00 PM
From: Time Traveler	Read Replies (1) \| Respond to of 1574212

Bill, The number of transistors are increasing from generation to generation. As you have pointed out, testing such a processor must be a real nightmare. That is the x86 family. When the next generation after Merced comes out, we will have a complete divorce from the archaic and burden-some x86. Testing of the processors should ease up again. John.

To: Bill Jackson who wrote (28073)	1/22/1998 10:59:00 PM
From: Elmer	Read Replies (1) \| Respond to of 1574212

<How will they test even production line CPUs in a timely manner when they get into the 50 million transistor area?(in a few years) > The purpose of production test is to screen out manufacturing defects and guarantee the device meets datasheet specifications. It is not intended to prove the logic is correct. That is another field, called logic validation and system validation. Once the logic is proven to be correct,(as is reasonably possible) then each device is assumed to be correct also, unless it contains a defect. Screen out the defects and there is no need to reprove the logic 100 million times. EP

To: Bill Jackson who wrote (28073)	1/22/1998 11:25:00 PM
From: Paul Engel	Read Replies (3) \| Respond to of 1574212

Bill - Re: "How will they test even production line CPUs in a timely manner when they get into the 50 million transistor area?" You have touched on a very important point. And there are methods to deal with them. Intel has included BIST (Built in Self Test) logic on their Pentium family processors so there is an initial series of tests (performed by the CPU itself) that is perfomed quite efficiently. The product engineers also hone the test suites - test vectors - improving test coverage and optimizing the test vectors to perform more internal logic coverage with more optimized test flows. This experience has been built up from almost 20 years of x86 production test experience. Also, as chips get faster - and assuming you can FIND a suitable logic testor that can run at these new chip speeds (500 to 800 MHz), the test times can be maintained just because the chips can be clocked faster. However, finding these testers isn't easy. There are very few vendors and the new testers are multi-multi-million dollar investments. Perhaps someone else on this thread can add some insight into the test difficulties with newer CPU chips? Paul