And the review determined that the two affected beams, both over 60 feet long, barely moved an inch due to the fractures. The redundancies in design guaranteed the beams’ stability. The overall safety of the building was never compromised. If those workers hadn’t discovered the cracks by chance, we still might not know about them.
For the scientists, that ends a mission of unexpected endurance. The rover was designed to last only three months. Opportunity provided scientists a close-up view of Mars that they had never seen: finely layered rocks that preserved ripples of flowing water several billion years ago, a prerequisite for life.
The last regular contact with the spacecraft was on April. 4. The spacecraft was in good health and operating as expected.
Kepler completed its prime mission in 2012, detecting nearly 5,000 exoplanets, of which, more than 1,000 have been confirmed. In 2014 the Kepler spacecraft began a new mission called K2. In this extended mission, K2 continues the search for exoplanets while introducing new research opportunities to study young stars, supernovae, and many other astronomical objects.
To save on bandwidth, Kepler only downlinks data from the pixels associated with 156,000 target stars out of the millions of stars in the Kepler field. Data from an “aperture” of pixels around each target star are downlinked to Earth, and computer programs on Earth measure the brightness of the star based on the light that hit the pixels in the aperture. If the telescope pointing is not good enough to keep the target stars in their respective apertures on the pixels, it is impossible to measure the brightness of those stars with a precision of 20 parts per million.
Once the spacecraft checks out, Kepler will kick off its latest effort, looking toward the galactic center for planets whose gravity distorts the light from far more distant stars. This technique, known as gravitational microlensing, has been used with ground-based telescopes to discover about 46 planets, some of them orphaned from their parent stars. But the method is a first for Kepler, which searches for dips in starlight caused by planets crossing in front of their suns.
Computers operating each engine cannot work if this data, which is unique to each of the turboprops, is missing.
Under the A400M’s design, the first warning pilots would receive of the engine data problem would be when the plane was 400 feet (120 meters) in the air, according to a safety document seen by Reuters. On the ground, there is no cockpit alert.
Sounds like these data files became a single point of failure.
It has been written many times in these pages, and it begs repeating: this rover was sent on a 90-day expedition, with the mission success mobility objective of driving 600 meters. In March, Opportunity completed 42.195 kilometers or 26.2 miles. It’s the first marathon “run” on another planet. And in April – the 4000th sol. “This rover just keeps giving and giving,” said Planetary Society President Jim Bell, professor of astronomy and planetary scientist at Arizona State University and lead scientist on the MERs’ panoramic cameras (Pancams).
The SSD Endurance Experiment represents the longest test TR has ever conducted. It’s been a lot of work, but the results have also been gratifying. Over the past 18 months, we’ve watched modern SSDs easily write far more data than most consumers will ever need. Errors didn’t strike the Samsung 840 Series until after 300TB of writes, and it took over 700TB to induce the first failures. The fact that the 840 Pro exceeded 2.4PB is nothing short of amazing, even if that achievement is also kind of academic.
If you write a lot of data, keep an eye out for warning messages, because SSDs don’t always fail gracefully.
Fault Tolerant Router is a daemon, running in background on a Linux router or firewall, monitoring the state of multiple internet uplinks/providers and changing the routing accordingly. LAN/DMZ internet traffic (outgoing connections) is load balanced between the uplinks using Linux multipath routing. The daemon monitors the state of the uplinks by routinely pinging well known IP addresses (Google public DNS servers, etc.) through each outgoing interface: once an uplink goes down, it is excluded from the multipath routing, when it comes back up, it is included again. All of the routing changes are notified to the administrator by email.
Unlike a normal virus scanner on consumer PCs that compares a catalog of known viruses to something that has infected the computer, A3 can detect new, unknown viruses or malware automatically by sensing that something is occurring in the computer’s operation that is not correct. It then can stop the virus, approximate a repair for the damaged software code, and then learn to never let that bug enter the machine again.
The A3 software is open source, meaning it is free for anyone to use, but Eide believes many of the A3 technologies could be incorporated into commercial products
Download papers from the source: A3 : Flux Research Group
The A3 project applies virtualization, record-and-replay, introspection, repair, and other techniques to develop a customizable container for “advanced adaptive applications.” The A3 container provides its protected application with both innate and adaptive defenses against security threats.
XenTT — a “time-traveling” hypervisor (docs and source code)
Chronos has a number of advantages over regular cron. It allows you to schedule your jobs using ISO8601 repeating interval notation, which enables more flexibility in job scheduling. Chronos also supports the definition of jobs triggered by the completion of other jobs, and it also supports arbitrarily long dependency chains.
In a complex processing pipeline every step increases the chance of failure. Until December last year, we were relying on a single instance with cron to kick off our hourly, daily and weekly ETL jobs. Cron is a really great tool but we wanted a system that allowed retries, was lightweight and provided an easy-to-use interface giving analysts quick insights into which jobs failed and which ones succeeded.