Thomas E. Cook

NStrace: a bus-driven instruction trace tool for PowerPC microprocessors

NStrace is a bus-driven hardware trace facility developed for the PowerPC® family of superscalar RISC microprocessors. It uses a recording of activity on a target processors bus to infer the sequence of instructions executed during that recording period. NStrace is distinguished from related approaches by its use of an architecture-level simulator to generate the instruction sequence from the bus recording. The generated trace represents the behavior of the processor as it executes at normal speed while interacting normally with its run-time environment. Furthermore, details of the processor state that are not generally available to other trace mechanisms can be provided by the architectural simulation. There are two main components to the process of generating bus-driven instruction traces: bus capture and trace generation. Bus capture is triggered by a call to a system program that puts a particular address on the bus, then establishes the initial state of the processor by a combination of writing out register values and invalidating caches. A logic analyzer records the bus activity, and from this a file of bus transactions is produced. Trace generation proceeds by driving a processor simulator with these bus transactions and recording the sequence of instructions that results. The processor simulator is an 3 elaboration of that developed for the PowerPC Visual Simulator. We have successfully generated instruction traces for a mix of utility programs and real applications on several microprocessor platforms running several operating systems. The capacity of the bus recording hardware is two million transactions, yielding instruction traces with lengths of the order of one hundred million instructions. This trace facility has been used for a number of studies covering a range of performance issues involving software, hardware, and their interactions.

Mobile innovation applications for the BYOD enterprise user

As employees began to bring their consumer mobile devices to the office, employees expected corporations to embrace or to provide solutions similar to consumer solutions they were used to on their smartphones. However, because of accountability and security concerns, many enterprises prefer employees use corporate alternatives to popular consumer apps. However, many of these expected enterprise alternatives to consumer solutions were not available to employees. In this paper, we discuss lessons learned during the BYOD (Bring Your Own Device) transformation process leading to the rapid development and deployment of internal alternatives to consumer applications, as well as the introduction of technologies to reduce the cost brought on by a large influx of mobile devices connected to the enterprise. We also discuss the importance of a filtered approach to access content through the firewall into the enterprise arena as an alternative to the full virtual private network approach granted to PC devices.

Extending Web Browsers with a Unity 3D-Based Virtual Worlds Viewer

Many virtual worlds are accessed via a rich client interface that must be downloaded and installed into the users environment. For many users, especially enterprise users, this large download and install represents a significant obstacle to virtual world acceptance. The authors describe a technical implementation that uses the Unity 3D browser plug-in as a way to access a virtual world from within a Web browser. Using this familiar tool, users can interact with the rich virtual environments provided by Second Life and OpenSimulator.

Implementing a cloud backed scalable note-taking application with encrypted offline storage and cross platform replication

The act of taking notes is second nature to most people in the business and academic world where note-taking can play a variety of important roles such as aiding memory recall of events, idea capture, problem solving or visualization of complex systems and concepts through the use of diagrams or sketches. Whilst the traditional paper based form of note-taking is sufficient in most cases and actually superior in others to digital note-taking, the digital form does have some compelling advantages including the ability to search through notes, back them up, have ubiquitous access to them and augment them with captured digital media. Implementing these digital enhancements presents a challenge especially when combined with a requirement to provide a highly secure storage environment to protect confidential notes. In this paper we describe an architecture that provides these features whilst maintaining a high level of scalability and security through the use of cloud based services.