computer tips

Monday, January 10, 2011

LCD (liquid-crystal display)

Short for liquid-crystal display. A low-power, flat-panel display used in many digital devices to display numbers or images. It is made of a liquid containing crystals that are affected by electric current, sandwiched between filtering layers of glass or plastic. LCDs do not produce light of their own; instead, when electric current is passed through the material, the molecules of the "liquid crystal" twist so that they either reflect or transmit light from an external  source.

Stands for "Liquid Crystal Display." LCDs are super-thin displays that are used in laptop computer screens and flat panel monitors. Smaller LCDs are used in handheld TVs, PDAs, and portable video game devices. The image on an LCD screen is created by sandwiching an electrically reactive substance between two electrodes. This color of this substance can be changed by increasing or reducing the electrical current. Since LCD screens are based on the principle of blocking light (rather than emitting it), they use up much less power than standard CRT (Cathode-Ray Tube) monitors.

What is a Sprint Backlog ? A short definition

I have been talking about the Product Backlog which is the repository of all the feature requirements, architectural work, and design changes required to be done by the team, and is owned by the Product Owner, typically from the Product Management team. However, there is another term called the “Sprint Backlog”. In this post, we will briefly talk about the Sprint Backlog, and its definition, and the next few posts will start to define the term in more detail.

The Sprint Backlog is the actual execution plan of a specific Sprint, and is owned by the Product team, and not by the Product Owner. It details the breakdown of the specific tasks that are planned for the current Sprint, and involves breaking down the features defined in the Product Backlog down into tasks, with these tasks being short bites of between 5 and 16 hours of work for each task. Once these tasks are defined, anybody can pick up specific tasks to implement, and indeed, the assignment of tasks is done by the Product team themselves. It is the team that sets the priority for the Sprint Backlog.

Wireless Mesh Definition

Wireless mesh technology was developed for the US Defense Department. Basically, it was a way for tanks on the battle field to communicate with one another and a central system. Each tank was an access point (AP). An AP would talk to its nearest AP who would relay the messages to another close AP, passing messages up and down the line. The network was smart in that you could take out one tank and it would heal itself, finding the shortest way back to the central command center.

Today, wireless mesh has evolved. Most mesh technologies still use a single radio for sending the information up and down the network as well as connect with a customer device like a phone or internet connection. In practical terms, this limits the speed (bandwidth) of the network, and also means that the system can go no further than 3 hops before it needs to find a connection into the internet fiber backbone as a single radio system loses, on an average, about two thirds of its speed over three hops.

WiMax and cellular technology systems are based on the single cell tower system. Mesh uses small radios or access points which are much cheaper to deploy and which connect to each other with many possible routes, passing information up and down the system.

iPod Definition

An iPod is a palm-sized, electronic device primarily created to play music. Unlike a traditional Walkman or portable CD-player, the iPod is capable of storing a large number of tracks and playing for many, many hours on a single battery charge.

The iPod owes much of its success not in what it does, but in how it does it. Apple, the creator of the iPod, seems to have found the perfect combination of simplicity and functionality. Plus, a clever marketing campaign and Apple's ongoing efforts to remain relevant, resulted in the iPod striking a chord with the right demographic in a way that no other portable music player has in recent times.

Bluetooth Definition

Bluetooth is a transmission specification for digital data exchange between 2 or more devices over short-range. This data can be anything including documents, images, and voice and the devices include PDAs, phones and desktop devices. The specific is an open standard allowing any one to take advantage of the opportunities it presents.

Unlike other wireless transmissions technologies, Bluetooth is intended to be used by devices that are close to each other. For instance, a PDA could transfer data such as a phone number to a cellphone. A laptop could transfer data such as e-mails to a PDA. With this technology, the need for wires and proprietary file transfer software could be eliminated.
Some examples of bluetooth applications are:
  • Wireless networking between desktops and laptops.
  • Bluetooth peripherals such as printers, mice, and keyboards.
  • Bluetooth cell phones have been sold in large numbers, and are able to connect to computers, personal digital assistants (PDAs) and, specifically, to hands free devices.
  • Certain mp3 players and digital cameras to transfer files to and from computers.
  • Bluetooth headsets for mobile phones.
  • Bluetooth car kits that allow users with Bluetooth-equipped cell phones to make use of some of the phone's features, such as making calls, while the phone itself can be left in a suitcase or in the boot/trunk, for instance.
  • For remote controls where infrared was traditionally used.

Definition of CPU

The CPU (central processing unit) is the part of a computer controls the interpretation and execution of instructions. Generally, the CPU is a single microchip, but that doesn't necessarily have to be the case. In the consumer desktop and laptop market, the CPU market is dominated by Intel, AMD, and IBM. These manufacturers supply the computer makers such as Dell, HP, and Apple.

Due to its importance to every computing task, the speed of the CPU, usually measured in gigahertz (GHz) is the number that most vendors use in their marketing campaigns. In the past, the larger the number, the faster the computer could be expected to be. However, in recent years, the speed of the CPU has had less impact as other components of a computer take on more and more of the workload. Also, differences in technology mean that a slower chip that performs more calculations per cycle can actually be faster than a higher rate chip doing fewer calculations per cycle.

RAM(Random Access Memory )

This is the area of where our data and instruction actually get stored .Every computer system has a specific storage capacity .In a typical Pc .We have 64 MB RAM, i.e. it has 64  1024 X 1024 location each capable of storing one byte, Each location has a unique address and in a RAM .The Contents of the memory are lost when power is switch off.
  It is used only to ‘Temporarily’ write or hold the data.