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jailbreaking                                                Published on: 15/2/2013

Jailbreaking, in a mobile device context, is the use of an exploit to remove manufacturer or carrier restrictions from a device such as an iPhone or iPad. The exploit usually involves running a privilege escalation attack on a user's device to replace the manufacturer's factory-installed operating system with a custom kernel.

Apple users often jailbreak iPhones and iPads to install programs that are not available through Apple's channels. Developers who don't wish to undergo Apple review or comply with Apple's AppStore rules often post apps on Cydia and other download sites used by jailbroken devices. Jailbreaking can also be used to bypass Digital Rights Management (DRM) and share copyrighted media, or to access file system, user interface, or network capabilities that are otherwise locked down.

However, jailbreaking increases the risk of malware infection or hacking. A jailbroken device can be easily victimized by aTrojan or accessed remotely by an intruder. Any security measures provided by iOS or installed third-party applications may be rendered inoperable or untrustworthy. As a result, employers often take steps to detect and then quarantine or wipe jailbroken devices

Gigabit Wi-Fi (802.11ac)                             Published on: 15/2/2013


802.11ac, also known as Gigabit Wi-Fi, is a proposed specification in the802.11family applicable to WLANs (wireless local area networks). 802.11ac represents an extension or update of the current 802.11a standard.

Networks using 802.11ac will operate in the 5-GHz(gigahertz) band using OFDM (orthogonal frequency-division multiplexing), just as 802.11a does. The enhancements supported by 802.11ac will facilitate simultaneous streaming of HD (high definition) video to multiple clients in homes and businesses, as well as faster wireless synchronization and backup of large files. New features that will exist in 802.11ac, in addition to those carried over from 802.11a, include:

  • Channel width up to 160 MHz (megahertz).
  • Single-link throughput of 500 Mbps(megabits per second) or more.
  • Multi-station WLAN throughput of 1 Gbps(gigabit per second) or more.
  • 400-ns(nanosecond) short guard interval.
  • Low-density parity check code.
  • Space-time block coding.
  • Up to eight spatial streams.
  • Transmit beamforming.

Finalization of the 802.11ac standard is expected in late 2012, with formal approval taking place by the end of 2013.

Open API                                                Published on: 15/2/2013


An open API, sometimes referred to as a public API, is an application program interface that provides a developer with programmatic access to a proprietary software application. An API is a software intermediary that makes it possible for application programs to interact with each other and share data. It's often an implementation of REST that exposes a specific software functionality while protecting the rest of the application.

Open APIs are published on the Internet and shared freely. A startup software company, for example might publish a series of APIs to encourage third-party developers in vertical industries to be innovative and figure out new ways to use the startup's software product. In theory, it's a win-win business arrangement.

The third-party developer can make money by licensing his new program, a mashup with advanced functionalities that would be almost impossible to create from scratch. The startup gets to expand their company's user base without having to spend any money to develop niche industry software -- and they still get to keep their source code proprietary.Open APIs can be problematic for developers, however, because the company publishing the API has all the power. If the startup ever decides to change the terms of use for its API, for example, or decides to charge a fee for licensing the API, the third-party developer has no choice but to accept it and deal with it.

OLTP                                                Published on: 5/10/2013


OLTP (online transaction processing) is a class of software programs capable of supporting transaction-oriented applications on the Internet.

Typically, OLTP systems are used for order entry, financial transactions, customer relationship management (CRM) and retail sales. Such systems have a large number of users who conduct short transactions. Database queries are usually simple, require sub-second response times and return relatively few records.

An important attribute of an OLTP system is its ability to maintain concurrency. To avoid single points of failure, OLTP systems are often decentralized.

Apache Cassandra                                                Published on: 15/2/2013


Apache Cassandra is an open source distributed database system that is designed for storing and managing large amounts of data across commodity servers. Cassandra can serve as both a real-time operational data store for online transactional applications and a read-intensive database for large-scale business intelligence (BI) systems.

Originally created for Facebook, Cassandra is designed to have peer-to-peer symmetric nodes, instead of master or named nodes, to ensure there can never be a single point of failure (SPoF). Cassandra automatically partitions data across all the nodes in the database cluster, but the administrator has the power to determine what data will be replicated and how many copies of the data will be created.

After Facebook open-sourced the code, Cassandra became an Apache Incubator project in 2008 and a top-level Apache project in 2010. As of this writing, Cassandra deployments include Netflix, Digg, Adobe, Twitter, HP, IBM, Rackspace, Cisco and Reddit. The name Cassandra was inspired by the beautiful mystic seer in Greek mythology whose predictions for the future were never believed.

Hadoop                                                Published on: 15/2/2013


Hadoop is a free, Java-based programming framework that supports the processing of large data sets in a distributed computing environment. It is part of the Apache project sponsored by the Apache Software Foundation.

Hadoop makes it possible to run applications on systems with thousands of nodes involving thousands of terabytes. Its distributed file system facilitates rapid data transfer rates among nodes and allows the system to continue operating uninterrupted in case of a node failure. This approach lowers the risk of catastrophic system failure, even if a significant number of nodes become inoperative.

Hadoop was inspired by Google's MapReduce, a software framework in which an application is broken down into numerous small parts. Any of these parts (also called fragments or blocks) can be run on any node in the cluster. Doug Cutting, Hadoop's creator, named the framework after his child's stuffed toy elephant. The current Apache Hadoop ecosystem consists of the Hadoop kernel, MapReduce, the Hadoop distributed file system (HDFS) and a number of related projects such as Apache Hive, HBase and Zookeeper.

The Hadoop framework is used by major players including Google, Yahoo and IBM, largely for applications involving search engines and advertising. The preferred operating systems are Windows and Linux but Hadoop can also work with BSD and OS X.

NAS storage                                                Published on: 15/2/2013


Network-attached storage (NAS) is hard disk storage that is set up with its own network address in order to provide file-based data storage services to other devices on the network. Network-attached storage consists of hard disk storage, including multi-disk RAID systems, and software for configuring and mapping file locations. Configuration, including the setting of user access priorities, is usually done through a Web browser.

NAS software can usually handle a number of network protocols, including Microsoft's Internetwork Packet Exchange and NetBEUI, Novell's Netware Internetwork Packet Exchange and Sun Microsystems' Network File System.

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