Microspeak: ZBB, recall class, glide path, and RTM

Raymond Chen

Raymond

Remember that Microspeak is not merely for terminology specific to Microsoft. It also covers terms in common use which you are expected to know because nobody will explain them to you.

In an old Microspeak entry, I included a snippet from an old document that included the sentence

Project XYZ is at ZBB and we are now at a recall class only bug bar until RTM.

I introduced this sentence in a discussion of the Microspeak phrase the plan for the plan which appears later in the document, but I never did get back to these other terms.

ZBB stands for Zero Bug Bounce, which is the moment that, even for only a brief shining moment, there were no active bugs in the database more than 48 hours old. The precise amount of time varies from team to team, but it means basically that there are no active bugs aside from the ones that just came in recently.

This is an important milestone because it means that the development team has fixed all their bugs, and they can reasonably be expected to fix new bugs shortly after they are discovered.

Eric Lippert discussed this topic in greater detail in 2004.

Related to ZBB is the glide path. Consider a graph that shows the number of active bugs as a function of time. You hope that as the product nears completion, this graph shows a line sloping down and to the right. Superimpose upon this graph a dotted line showing management’s prediction of active bugs in the future, with the dotted line reaching zero at ZBB. That dotted line is the bug glide path, or simply the glide path.

Note that I’m using the word prediction euphemistically.

The term probably relates to the use of the term landing to refer to when something will be completed.

The next piece of Microspeak in that sentence is recall class. This term has its origin in the days when software was distributed in physical media, purchased in stores. A recall-class bug is a bug so severe that you would issue a product recall, shutting down the factory and asking all the warehouses to send back all their copies of the product.

Cyrus Najmabadi discussed this topic in greater detail in 2005.

The last Microspeak term is RTM, which is short for Release to Manufacturing. (The T is capitalized even though the word to is not normally capitalized in titles.) This term also has its origin in the days when software was distriubuted in physical media. It originally referred to the point at which the final product is delivered to factories for mass production. Today, it refers to the point at which the final product is delivered to whatever process gets the product into customers’ hands.

You might think that the term RTM is obvious, but I was having a discussion with a person who was only a few years out of college. I used the term RTM, and the person asked me, “Um, what is RTM?”

Kids these days.

Raymond Chen
Raymond Chen

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