Those contracts are reliable in that the customer is extremely unlikely to move to a different product line. Especially when you've got a customer locked in, r

Those contracts are reliable in that the customer is extremely unlikely to move to a different product line. Especially when you've got a customer locked in, refresh timescales are pretty predictable. HPC contracts are generally borne of federal-agency RFPs, and are extremely competitive, and they only 'pay out' upon a passed acceptance test, so it's not trivially possible to predict which quarter your revenue will land for a given sale. You wind up with sales teams putting tons of work into a contract that didn't get selected, which sucks, but even if you win you might wind up missing sales goals, and then overshooting the mark the following quarter. In a company less hidebound this obviously wouldn't be a problem, but IBM has been run by the beancounters for long enough that the prestige isn't worth the murky forecast.