Emulation Vs. Simulation

There is a vast number of computer systems in use today. From the computer on our desktops and the phones in our pockets, to the electronic brains within our cars, ATMs, airplanes, the number of different architectures is constantly growing. These systems require programming and training, which involves the use of either a simulator or an emulator. Though similar in their use, simulators and emulators are two different styles of providing an imitation of another system.

Purpose of Simulation and Emulation

• Simulators and emulators share a common purpose: the imitation of one complicated system with another complicated system. There are a variety of needs for these systems. For example, a programmer needs to create the software for a variety of devices on a desktop computer, and uses emulators and simulators to mimic the device before installing the new software. Another example is the use of simulators for training purposes, especially when the activity is dangerous to do untrained. Even modern gaming consoles will use emulators to allow gamers to play games from older systems on newer devices.

Definition of a Simulator

• A simulator is a software or hardware system that mimics another complicated system, with a varying level of reality. A lot of simulators are software-based. A large subset of video games are simulations, such as city simulators, war simulators and flight simulators. While video game simulators are not very realistic, highly realistic simulators like airline training simulators not only include ultra-realistic physics and details in the software, they also usually include hardware with realistic controls and feedback.

Definition of an Emulator

• Emulators are limited to imitating computer hardware systems. In short, emulators are computer system simulators. For example, there are emulators for just about every kind of phone that runs on desktop computers. These emulators allow programmers to write software for the emulated system without needing the hardware in hand. This saves time and money in development. Other uses include legacy support. Modern video game consoles use emulators to mimic the hardware of their previous incarnations. As computers evolve, emulation is required to run software that was written for older systems.

Other Uses for Simulators

• Simulators have a myriad of uses. Public organizations use simulations to model the growth and spread of disease in various settings and the effects of disasters, such as flooding and tornados. Scientists use simulations to model physical systems to the point that computational science is a growing field with its own journals. Manufacturers use simulations to model and design products before money is spent making them. Artificial intelligences use simulation to learn and build their database of knowledge. Simulation and emulation has proven itself an important tool in this modern age.

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  Emulation

  • Emulation is making one computer act like a different computer. One of the most popular applications of emulation technology is using an emulator program to run gaming software from outdated computers, like the Commodore 64, on new PCs. Gaming emulators can also make PCs run games from older consoles like Nintendo or Sega Genesis. Another practical application of emulation software is to emulate the OS, or operating system, of a different computer. An emulator can be used this way to make Mac software run on a PC or vice-versa.

    Legality

    • Emulators that allow computers to run software from other types of computers, or even gaming consoles are perfectly legal. Many emulators are freeware and open source, meaning anyone can download them and anyone has access to the actual programming code. But many of the games that can be played through emulators are illegal. The read only memory games, or ROMs, are usually copies of copyrighted software. Those are illegal to distribute or download.

    Other Devices

    • 

      Emulators aren't only made for computers. Emulators are available for iPods, iPhones, Blackberries, Google's Android and other "smart" devices. Most of these emulators are designed primarily for game play. Some of them are fully and legally licensed and some are more homemade versions available for free.

    Simulation

    • Simulation is also a from of mimicry, but it is different than emulation. A simulation is a computer recreation of a particular scenario. Simulations are designed to act like an authentic system or situation. Simulations are popular in the gaming world, one of the first being Microsoft's Flight Simulator. Many other games allow users to recreate theme parks, restaurants or historical battles. The Sims series is just a simulation of everyday life.

    Other Uses

    • 

      Simulations are valuable scientific tools. They are common in physics, biology, chemistry and engineering. They can allow scientists to study virtual scenarios that may be impossible to actually create. Simulations are also used in economics, mathematics, sociology and other fields. Simulators are also an integral part of flight training programs for pilots. Microsoft's Flight Simulator is just a game, but real flight simulators create a realistic, but perfectly safe experience for pilots in training.

      
      

      source: www.ehow.com

Inside the iPhone 5: What makes it tick

Apple's A6 chip is big step up from the A5, according to analysts. Qualcomm's newest 4G LTE silicon is a major improvement too.

The Apple A6 chip. The combo CDMA-LTE Qualcomm chip is at bottom.

(Credit: Apple)

Apple's revamp of the iPhone included an overhaul of the inside too. So, what new silicon did Apple drop into the iPhone 5's chassis?

A6 chip: It's faster! (duh). Here's a summary of what Apple says. "Up to twice as fast compared with the [iPhone 4S' A5 chip]...The A6 chip also offers graphics performance that's up to twice as fast as the A5."

Problem is, Apple doesn't say much beyond that. So, I asked Anand Shimpi from chip review site Anandtech. While some of it's guesswork until reviewers decap the chip, Anand is usually on the money.

Based on the performance gains, he believes the A6 is based on an ARM Cortex-A15 design. That's the latest and greatest from ARM, the chip architecture that powers virtually all of world's major-brand smartphones.

This is pretty big because, if true, it means Apple's chip is truly cutting edge. "It looks like Apple has integrated two ARM Cortex A15 cores on Samsung's [32 nanometer manufacturing] process. This is a huge deal because it means Apple beat both [Texas Instruments] and Samsung on bringing A15s to market," he wrote in a blog post today.

The graphics processing unit is less clear but Anand believes it could be using four Imagination PowerVR SGX543 cores, doubling the GPU core count in theiPhone 4S.

Another analyst believes Apple is able to balance increased performance with decent battery life because of tweaks done independent of the main central processing unit, or CPU.

"In order to get double the performance but still have good battery life, more than likely it's because they have beefed up peripheral cores," said Francis Sideco, an analyst at IHS iSuppli. "Those are GPUs, accelerators that are peripheral to the main core," he said.

Source: CNET News

QR Code : Explained

QR Code - A common term that is seen in the media that reads "Scan your smartphone here to get more details". Its a modified version of Bar-Code that has some added features of readability even in damaged code. QR Code is the one that comes with auto error correction. So what is QR Code?

QR Code - Quick Response Code is a combination of Black and White squares as it is below:

The most beauty part of it is that any one can make this code and any one can generate them for free. Of course the unique one. Once the QR Code is generated or created, one can modify its colour, graphics, or even one can mess it up! One needs not to be a great hacker to crack the code, just knowing the basics can make it all.

QR Code is a 2 dimensional code that is categorized in matrix code. 

The features of QR Code are:

1. High speed in reading the code.
2. Error correction.
3. High capacity.

Since the QR Code has been created, it is available in two models- Original and Extended model. Extended model is the one in use now-a-days. Depending upon the number of characters used, the size of the QR Code changes. More the characters, big is the size. Though it can hold any number of characters, QR Code scanner (smartphone!) finds difficult to scan the code. 

Versions and Character encoding:

Depending upon the size of the QR Code, the version number changes. There are around 40 versions available starting from 21*21 grid pattern for version 1 to 177*177 grid pattern for version 40. QR Code can hold:

• Numeric characters(0-9) - 10 Characters
• Alpha-Numeric characters(0-9 A-Z special symbols) - 45 Characters
• 8-bit data
• Multi Byte data

Know QR Code:

• Three large squares marked RED are position markers. These tells the scanner where the edge is.
• A single small square in RED is an alignment  marker that tells the scanner that the codes are lined up properly. Their number increase when the size of the grid increases as here.
• RED stripes that runs over the alternative white and black squares is a timing pattern, defines the position of number of rows and columns.
• GREEN tells the format of the QR Code as it is a website or text message or a phone number.
• BLUE area describes the version number used in the QR Code. (It is already discussed few lines before)

Here is a pictorial representation. These areas are the sensitive ones and other areas can be changed depending upon your data.

Error Correcting:

An added feature of QR Code is error correcting. QR Code defines 4 levels of error correction in case the white and black squares are misread. 

• Level L: Up to 7% of the error can be corrected.
• Level M: Up to 15% of the error can be corrected.
• Level Q: Up to 25% of the error can be corrected.
• Level H: Up to 30% of the error can be corrected.

Because of this error correction, you can create an error for sure as it is here.

You can do even like this as it is Here. It is still readable until you don't touch the sensitive areas as it is described above.

Now you can create your own QR Code for your Products or Website or E-Mail or Phone Number... Or generate online here for free. Google can fetch you some more online QR Code generators.

Domain Types

There are many types of domain in the internet world. Here I do not mean it as .com or .co.in or something like that. I come to say about Parked Domains, Sub-Domains, Add-on Domains and Redirects.

Parked Domain
Suppose, say you have two domain names like mydomain.com and my-domain.com. If you want the users to point to the same website from mydomain.com and my-domain.com, then this is the right choice for you, which means that when the users type mydomain.com or my-domain.com, DNS (Domain Name Server) will direct the user to the same website.

Try it: Everyone knows Google website. You just type www.google.com to access that website. Have you just tried www.gooogle.com or www.ggoogle.com? You may wonder that it all directs you to same page!
This is the use of Parked Domain.



Sub-Domain
An online company wants to have a forum website for its main website. Though the forum is needed for it, they do not buy another website for forum, instead they use the existing website as the link to it. In other words, sub-domain utilizes the existing domain name. Consider mycompany.com is a company's domain name, if it wants to add a forum page to its website and to be shown as a unique one, it just creates a sub-domain as: forum.mycompany.com. Its just the concept of replacing www with your own words.

Know it: forum.mycompany.com is a sub-domain and it also can be called from www.mycompany.com/forum
This is how the sub-domain can be used as a unique domain. Sub-domains are usually free and is most preferred in order not to change a domain.



Add-On Domain
It is like having two seperate domain names with different contents but with the same hosting account, which means your content is split in public_HTML folder inside your hosting account itself. Main account and Add-on account uses same bandwidth of the hosting account but different nameserver. Here the advantage is that add-on domain can be accessed either separately or can be accessed from you main account as :

addondomain.com
maindomain.com/addondomain
addondomain.maindomain.com



Redirects
This is different from those previously discussed domain types. Those domain names are dependent on your webhosting plan. But Redirect is the concept that you point out a website either to your blog or a social networking profile or even a website hosted in a different web server. Some redirects allow you to point out your IP address similar to the DNS address. The Redirecting server do not host your website or its contents rather it stores the URL that is to be redirected when the redirecting URL is entered in the address bar. Some services even allows masking of the real redirecting URL and displays their URL.

CDPD vs CMDA vs GSM vs GPRS vs EDGE

CDPD :


Cellular Digital Packet Data

• Packet-based network.
• Optimal bandwidth of 19.2 Kbps.
• Run in the same spectrum as the AMPS networks.

CDMA :

Code Division Multiple Access

• Either packet based or circuit based.
• CDMA1 :  Uses circuit switch data, that runs at 14.4 Kbps, and acts as a dial-up connection.
• CDMA2000 : packet based, and has a maximum of 144 Kbps, and delivers 50-120kbps in real world usage.

GSM :

Global System Mobile Communication

• Circuit-based network.
• The user must make a dial-up connection to access the network.
• Optimal bandwidth of 14.4 Kbps.
• Provides voice service through digital network.
• SIM card (Subscriber Identity Module card) stores phone number, connection information, and may store an address book. 
• This allows a user to switch devices without needing to contact the service provider.

GPRS :

General Packet Radio Service

• Packet-based wireless communication service.
• Extends the GSM network that allows for advanced data services.
• Data rates from 56 up to 114 Kbps and continuous connection to the Internet for mobile phone and computer users, but delivers in the 30-50 Kbps in real world usage.
• Advantage over GSM is that one can use the device as the modem or as an Web-Browser.

EDGE :

Enhanced Data for Global Evolution

• An extension to the GSM / GPRS networks.
• 3 times faster than GPRS.
• Download speed extends about 300 Kpbs.