OpenFlow: A Radical New Idea in Networking

An open standard that enables software-defined networking


Computer networks have historically evolved box by box, with individual network elements occupying specific ecological niches as routers, switches, load balancers, NATs (network address translations), or firewalls. Software-defined networking proposes to overturn that ecology, turning the network as a whole into a platform and the individual network elements into programmable entities. The apps running on the network platform can optimize traffic flows to take the shortest path, just as the current distributed protocols do, but they can also optimize the network to maximize link utilization, create different reachability domains for different users, or make device mobility seamless.
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Related: Beyond Beowulf ClustersSoC: Software, Hardware, Nightmare, BlissTCP Offload to the Rescue

Extending the Semantics of Scheduling Priorities

Increasing parallelism demands new paradigms.


Application performance is directly affected by the hardware resources that the application requires, the degree to which such resources are available, and how the operating system addresses its requirements with regard to the other processes in the system. Ideally, an application would have access to all the resources it could use and be allowed to complete its work without competing with any other activity in the system. In a world of highly shared hardware resources and general-purpose, time-share-based operating systems, however, no guarantees can be made as to how well resourced an application will be.

Related: Real-World ConcurrencyPerformance Anti-PatternsAbstraction in Hardware System Design

LinkedIn Password Leak: Salt Their Hide

If it does not take a full second to calculate the password hash, it is too weak.


6.5 million unsalted SHA1 hashed LinkedIn passwords have appeared in the criminal underground. There are two words in that sentence that should cause LinkedIn no end of concern: “unsalted” and “SHA1.”

A Nice Piece of Code

Colorful metaphors and properly reusing functions


In the last installment of Kode Vicious (A System is not a Product,ACM Queue 10 (4), April 2012), I mentioned that I had recently read two pieces of code that had actually lowered, rather than raised, my blood pressure. As promised, this edition’s KV covers that second piece of code.

ACM Webinar: 2012 – Big Data: End of the World or End of BI?

Thursday, June 28, 2012 at 12:00 PM EDT/11:00 AM CDT/9:00 AM PDT/4:00 PM UTC

According to some, the world will end at the Winter Solstice this year. If not, it’s certainly time to take a closer look at Business Intelligence (BI) and ask: “After 20 years, is it still fit for purpose? Can it deliver the type of support needed for decision-making in the next decade?” We are witnessing the birth of a new “biz-tech ecosystem,” where business and technology have become symbiotic and collaborative behavior is the norm. In this environment, decision-making is very different from what is supported by today’s BI.

This webinar explores the emerging ecosystem and poses some interesting challenges for BI vendors and implementers in 2013… Assuming we’re all still here…

Registration and more information:
What you’ll learn about:

  • The meaning and emergence of the biz-tech ecosystem
  • The re-convergence of operational and informational systems
  • Data, information and knowledge – reopening Pandora’s Box
  • Millennials and team decision making – the whys and wherefores
  • Architectural models for 2013 and beyond