syslog
12Jun/120

HotCloud 2012 — Day 1

Posted by Malte Schwarzkopf

I am a visiting preacher at HotCloud today, delivering a sermon about the seven deadly sins of cloud computing research. Of course, syslog provides you with the usual live-blogging service, although some sessions may be missing, as I nip out to work on a soon-to-be-submitted paper!

Here goes the first day...

13Apr/120

Liveblog: EuroSys 2012 — Day 3

Posted by Malte Schwarzkopf

EuroSys 2012Various people from Cambridge are currently in Bern für EuroSys 2012, and will be reporting live from the conference here, as well as summarizing the trends and highlights afterwards.

The final day of the conference starts with a keynote from Steve Furber, followed by two more sessions. Click the link to read the details!

12Apr/120

Liveblog: EuroSys 2012 — Day 2

Posted by Malte Schwarzkopf

EuroSys 2012Various people from Cambridge are currently in Bern für EuroSys 2012, and will be reporting live from the conference here, as well as summarizing the trends and highlights afterwards.

The second day has kicked off, and we will be providing the usual live update service below the fold -- click "continue reading" to get there!

11Apr/122

Liveblog: EuroSys 2012 – Day 1

Posted by Malte Schwarzkopf

EuroSys 2012 Various people from Cambridge are currently in Bern für EuroSys 2012, and will be reporting live from the conference here, as well as summarizing the trends and highlights afterwards.

So here goes -- we're kicking off. Read more below the fold!

12Apr/110

EuroSys 2011, day two

Posted by Derek Murray

Session 4: Joules and Watts

Energy Management in Mobile Devices with the Cinder Operating System

A new mobile device OS, whose aim is to allow users to control their energy use, and allow applications to become more energy-efficient. First abstraction is throttling, which limits the draw that a particular application may have. However, the energy use is bursty, so this uses a reserve buffer that allows an application to use more energy if it has been running below maximum for a while. A process with an empty reserve will not be scheduled. To prevent hoarding of energy, the reserve drains with multiplicative decrease (e.g. 10%/sec). Reserves may be nested, to, for example, isolate the energy usage of a plugin like Adobe Flash. Energy may also be ring-fenced in "virtual batteries" for uses such as emergency calls. The OS abstraction is a process launcher called "enwrap", which launches an application with an allocation of power consumption. Background applications draw power from a smaller virtual battery to prevent unexpected power draw from applications you can't see; this is managed via a custom window manager. Development issues arose from the implementation of the HTC Dream, which uses a binary blob shared object to interact with the secure ARM9 core, and the exposure of the battery level as an integer 0 to 100; this led to concerns that future mobile phones will be more difficult to develop research OSs for, as there is a move to more use of secure cores and signed code. As a result of these frustrations, they moved to implement their abstractions in Linux, giving Cinder-Linux. One challenge was IPC: it was necessary to attribute energy use in daemons to the process making the IPC request. (This was easier in Cinder due to the use of gates, based on the same mechanism in HiStar.) One application developed was an energy-aware photo gallery, which modulated its download rate depending on energy properties. Next step is working out how to use these primitives, in terms of UI design (presenting a breakdown of energy use to users), energy modeling (currently use a simple energy model based on offline profiling, but could use something more sophisticated such as the approach described in the following talk), userspace code instrumentation and running Android (Dalvik) on Cinder.

11Apr/110

EuroSys 2011, day one

Posted by Derek Murray

Session 1: Data, Data, Data

Keypad: An Auditing File System for Theft-Prone Devices

The challenge is that mobile devices are prone to theft and loss, and encryption is not sufficient, because people have a habit of attaching the password to the device on a post-it, and it is vulnerable to social and hardware attack. Aim is to know what (if any) data is compromised in the event of a loss, and prevent future compromises. Solution is to force remote auditing on every file access (with encryption), by storing keys on the auditing server; this is done in the file system. File system metadata are stored on the trusted server. There are significant challenges in making this performant: caching/prefetching/preallocation are used to optimize key requests, but file creation is more challenging to optimize due to file systems semantics. Blocking filename registrations have correct semantics, but poor performance; vice versa for non-blocking registrations. To reconcile this, force a thief to use blocking semantics while allowing the user to use non-blocking semantics (as much as possible), which is based on using filenames as public keys. Second challenge is allowing disconnected access: the idea is to use multiple devices carried by the user to cross-audit file accesses, which still requires devices to hoard keys before going disconnected. - dgm36

17Mar/110

On the road: FAST 2011

Posted by Malte Schwarzkopf

I recently had the opportunity to attend FAST (the USENIX Conference on File and Storage Technologies) in sunny San José. Despite "only" running for two days, the program was packed with presentations of interesting research papers.

Back in Cambridge, I gave a trip report (slides), and have also made my (rough, unedited -- proceed with caution) notes available.