Pinpoint: A Record, Replay, and Extract System to Support Code Comprehension and Reuse

Abstract

Block-based programming environments, such as Scratch and Snap!, engage users to create programming artifacts such as games and stories, and share them in an online community. Many Snap! users start programming by reusing and modifying an example project, but encounter many barriers when searching and identifying the relevant parts of the program to learn and reuse. We present Pinpoint, a system that helps Snap! programmers understand and reuse an existing program by isolating the code responsible for specific events during program execution. Specifically, a user can record an execution of the program (including user inputs and graphical output), replay the output, and select a specific time interval where the event of interest occurred, to view code that is relevant to this event. We conducted a small-scale user study to compare users' program comprehension experience with and without Pinpoint, and found suggestive evidence that Pinpoint helps users understand and reuse a complex program more efficiently.

RR-Row: Redirect-on-Write Based Virtual Machine Disk for Record/Replay

“…Lee et al propose a tool for recording and replaying Android APIs to analyze the evasion techniques used in sophisticated malware [12]. Wang et al present Pinpoint, a system that records execution of the program (including user inputs and graphical output) and replays the output [14]. In this way, it helps Snap!…”

“…The main advantage is that it is able to provide the record/replay ability at the instruction level so that deterministic fine-grained operation can be achieved stepby-step upon replay. Due to the benefit, it is used in many scenarios such as hot-standby, live migration, fault tolerance, software debugging, security analysis, and so on [5]- [14].…”