zbackup is a globally-deduplicating backup tool, based on the ideas found in rsync. Feed a large .tar into it, and it will store duplicate regions of it only once, then compress and optionally encrypt the result. Feed another .tar file, and it will also re-use any data found in any previous backups. This way only new changes are stored, and as long as the files are not very different, the amount of storage required is very low. Any of the backup files stored previously can be read back in full at any time. The program is format-agnostic, so you can feed virtually any files to it.

This is achieved by sliding a window with a rolling hash over the input at a byte granularity and checking whether the block in focus was ever met already. If a rolling hash matches, an additional full cryptographic hash is calculated to ensure the block is indeed the same. The deduplication happens then.

Multi-robot systems promise to provide efficient solutions for an ever increasing variety of different applications, such as exploration of hostile environments, disaster recovery, construction, and nano-scale medicine.

Each of these applications is characterized by several aspects, such as environment dynamics (e.g. orbit, water flow, wind, rough terrain, bloodstream), robot types (e.g., mechatronics, sensors, actuators), and communication means (e.g., wifi, vision, stigmergy, etc.).

Physics-based simulation plays a fundamental role in the study of solutions for this wide set of applications.

Joy as mathematicians discover a new type of pentagon that can cover the plane leaving no gaps and with no overlaps. It becomes only the 15th type of pentagon known that can do this, and the first discovered in 30 years.

Schaak! is very interesting.

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