Wednesday, January 22, 2014

ideas: Liquid Cooling for Data Centers

Is There a Liquid Fix for the Cloud’s Heavy Energy Footprint? - IEEE Spectrum: "Because liquids are denser than gases, they are a more efficient medium to transport and remove unwanted heat.

Yet direct liquid cooling is a rarity in the corporate data centers that run bank transactions and the cloud facilities that serve data to smartphones. Data centers consume more than 1 percent of the world’s electricity and about 2 percent of the electricity in the United States. A third or more of that expenditure is for cooling."

example: Asicminer’s 500-kilowatt computing system uses 97 percent less energy on cooling than if it employed a conventional method.

Paxos protocols

Paxos (computer science) - Wikipedia, the free encyclopedia:

Paxos is a family of protocols for solving consensus in a network of unreliable processors. Consensus is the process of agreeing on one result among a group of participants. This problem becomes difficult when the participants or their communication medium may experience failures.[1]

Consensus protocols are the basis for the state machine approach to distributed computing, as suggested by Leslie Lamport[2]and surveyed by Fred Schneider.[3] The state machine approach is a technique for converting an algorithm into a fault-tolerant, distributed implementation. Ad-hoc techniques may leave important cases of failures unresolved. The principled approach proposed by Lamport et al. ensures all cases are handled safely.


Another (ugly) acronym:

HATEOAS - Wikipedia, the free encyclopedia

HATEOAS, an abbreviation for Hypermedia as the Engine of Application State, is a constraint of the REST application architecture that distinguishes it from most other network application architectures. The principle is that a client interacts with a network application entirely through hypermedia provided dynamically by application servers. A REST client needs no prior knowledge about how to interact with any particular application or server beyond a generic understanding of hypermedia. In aservice-oriented architecture (SOA), clients and servers interact through a fixed interface shared through documentation or aninterface description language (IDL).

RESTful service can be described as well to be available for the client code-generation, RSDL (RESTful Service Description Language) using dynamic metadata collection to achieve this goal.

The HATEOAS constraint serves to decouple client and server in a way that allows the server to evolve functionality independently.

REST APIs must be hypertext-driven » Untangled
(by inventor of REST, and co-author of HTTP)

if the engine of application state (and hence the API) is not being driven by hypertext, then it cannot be RESTful and cannot be a REST API. Period.