Writing process logs (keystroke logs) provide an excellent source of information about how writers have distributed their time and attention across the course of a writing task. However, relatively little is known about how the features that can readily be collected from such logs vary as a result of changes in writing task demands. In this study, we contrast the writing behavior of 463 8th-grade students in a school with low socioecomonic status in the western U.S. under 3 conditions: when they were copy typing (retyping an article), when they were drafting an essay, and when they were editing the essay they had drafted in a previous session. We observed striking differences in the characteristics of the resulting keystroke logs, reflecting differences in the mix of writing processes emphasized in each task. Copy typing was characterized by relatively slow typing, little time spent on long pause behaviors (except between words, when writers would have been scanning the text they were copying), and strictly local editing events. Drafting was characterized by relatively fluent typing, significant amounts of backspacing (reflecting false starts and sentence-level revision and editing), significantly longer pauses at sentence and word boundaries (reflecting idea generation and the process of translating ideas into words), and a moderate amount of time spent jumping to points within the most recently produced sentence to sentence in order to make edits to phrasing. Editing was characterized by very long pauses before jumping to another location to the text to make an edit, with very little time spent typing out individual words, phrases, or sentences. These differences indicate the importance of interpreting keystroke logs in the light of task demands and suggest that different features will be provide significant information about writers’ performance, depending on the writing processes most emphasized in a particular literacy task.