Facilitating the Development of Soft Devices

Device-level interfaces in operating systems present a very useful cut-point for researchers to experiment with new ideas. By virtualizing these interfaces, developers can create soft devices, which are used in the same way as normal hardware devices, but provide extra functionality in software. Recent years have shown this approach to be of considerable interest: a few examples of block device extension include the addition of intrusion detection systems to disk interfaces [1], the development of “semantically smart” disks [2], and that of time-travel block devices [3]. Other devices, such as network interfaces, have similarly been extended.