Storage has become a constrained resource on smartphones. Gaming is a popular activity on mobile devices and the explosive growth in the number of games coupled with their growing size contributes to the storage crunch. Even where storage is plentiful, it takes a long time to download and install a heavy app before it can be launched. This paper presents AppStreamer, a novel technique for reducing the storage requirements or startup delay of mobile games, and heavy mobile apps in general. AppStreamer is based on the intuition that most apps do not need the entirety of its files (images, audio and video clips, etc.) at any one time. AppStreamer can, therefore, keep only a small part of the files on the device, akin to a "cache", and download the remainder from a cloud storage server or a nearby edge server when it predicts that the app will need them in the near future. AppStreamer continuously predicts file blocks for the near future as the user uses the app, and fetches them from the storage server before the user sees a stall due to missing resources. We implement AppStreamer at the Android file system layer. This ensures that the apps require no source code or modification, and the approach generalizes across apps. We evaluate AppStreamer using two popular games: Dead Effect 2, a 3D first-person shooter, and Fire Emblem Heroes, a 2D turn-based strategy role-playing game. Through a user study, 75% and 87% of the users respectively find that AppStreamer provides the same quality of user experience as the baseline where all files are stored on the device. AppStreamer cuts down the storage requirement by 87% for Dead Effect 2 and 86% for Fire Emblem Heroes.

中文翻译：

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AppStreamer：通过预测流降低移动游戏的存储要求

存储已成为智能手机上的受限资源。游戏是移动设备上的一项流行活动，游戏数量的爆炸性增长及其不断增长的规模导致了存储紧缩。即使在存储空间充足的情况下，下载和安装繁重的应用程序也需要很长时间才能启动。本文介绍了 AppStreamer，这是一种新技术，用于降低移动游戏和一般重型移动应用的存储要求或启动延迟。AppStreamer 基于大多数应用程序在任何时候都不需要其全部文件（图像、音频和视频剪辑等）的直觉。因此，AppStreamer 只能在设备上保留一小部分文件，类似于“缓存”，并在预测应用程序在不久的将来需要它们时从云存储服务器或附近的边缘服务器下载剩余部分。AppStreamer 会在用户使用应用程序时不断预测近期的文件块，并在用户看到由于缺少资源而停顿之前从存储服务器中获取它们。我们在 Android 文件系统层实现 AppStreamer。这确保了应用程序不需要源代码或修改，并且该方法可以跨应用程序推广。我们使用两款流行游戏评估 AppStreamer：3D 第一人称射击游戏 Dead Effect 2 和 2D 回合制策略角色扮演游戏 Fire Emblem Heroes。通过用户研究，分别有 75% 和 87% 的用户发现 AppStreamer 提供与所有文件都存储在设备上的基准相同的用户体验质量。