Computers & Technology

Citrix came up with their new product XenApp 6 brings a bunch of new features that most emerging companies will need as the technology continues to evolve and the client requirements continues to expand. These features and benefits include:

•Simple Installation
•Single Administrative Console
•Introduction of Worker Groups
•Citrix Policies and GPO Integration
•Merchandizing Server and Dazzle
•HDX MediaStream for Flash
•Provisioning Server Technology

1.1. Simple Installation

With the introduction of XenApp 6, Citrix introduced a number of enhancements to the installation wizard. Replicating from Microsoft's "Manage your Server" and roles concepts, Citrix adopted a similar process for installing XenApp. The Figure below depicts a typical Citrix Farm Architecture.

At the time of installation of XenApp, the administrator is allowed to choose the specific roles of a particular server that it will play in the XenApp Farm. Small Citrix farms typically have the following roles.
•Web Server
•License Server
•Application Server
•Database Server

Although the Farm Data Store (Database Server) is an essential part of the Farm, it is not technically a role. In fact, it is not a Citrix Server at all. It is a database server, typically SQL (can be Oracle or MS Access) that contains critical Farm Data. At the time of configuring the wizard for XenApp6, the administrator can designate the place where the Data Store will be located.

In larger environments, the Citrix Farms are much more complex and compact in the architectural level. They include other essential and value adding components like Provisioning Services, EdgeSight monitoring, Dedicated Data Collectors, Remote Access Devices, Secure Access Gateway and increased redundancy with all essential servers.

Another change to the install process is that there is no configuration required during installation. This makes the installation of each Server roles very easy to handle. Once the installation is completed, the administrator is prompted to configure each of the roles.

1.2. Single Administrative Console

Over the last decade one challenge for Citrix administrators has been the different consoles for doing different kinds of Farm management tasks. XenApp 6 has conglomerated almost all administrative tasks in one console called the Delivery Services Console.

Delivery Services Console

With this new Citrix Delivery Services Console, a Citrix administrator can use one console to perform all the required tasks like Publishing Applications, Creating Policies, and Managing Worker Groups and Zones, along with many other tasks. With a single console, it became easy to manage hundreds of servers and applications in a Citrix Server Farm.

1.3. Introduction of Worker Groups

Generally, each and every XenApp Server in the Citrix Farm would look the same. It would have all of the same applications installed, and there would be no compatibility issues or DLL conflicts between applications. Unfortunately, it is not the case every time. In some cases, we have complicated environments that sometimes require different applications to be installed on different XenApp servers. We have to deal with huge Clients with world-wide offices with geographically dispersed data centers and file servers. There are Test Environments, Production Environments, Segregated Contractor DMZ Servers, and many other scenarios we refer to as Application Silos. Application Silos are common in Citrix Farms, not because they are preferred but because they are required.

Worker Groups

In the former releases of Citrix, Application Silos were managed in a very manual way by only installing and publishing certain applications to some definite Citrix servers. But in XenApp 6, Citrix has introduced Worker Groups concept. Worker Groups paves the way to manage all servers within an Application Silo as one object. This allows us to publish applications and set a particular policy on a specific Worker Group rather than individual servers, making managing complex real-life Citrix environments much easier.

Moreover the Worker Groups can Perform Load Balancing between geographical locations or direct users to the XenApp servers closest to their current location.

1.4. Citrix Policies and GPO Integration

There must be a balance between allowing users to do what they need to do without exposing them to unnecessary risk and Outage. These controls are executed via policy. Before XenApp 6, the Microsoft policies (GPOs) were controlled with one console, and the Citrix policies were managed with another separate console. Citrix Administrators can now use GPOs and Organizational Units (OUs) to manage their Citrix Policies just like they do their Microsoft Policies, giving Administrators one tool to manage user rights.

GPO Integration If one doesn’t have rights at an Active Directory Level, XenApp6 does still allow for IMA-Based Polices, which is stored in the Citrix Data Store. These policies are created using the Delivery Services Console; however, they are superseded if GPO-Based Citrix Policies exist.

1.5. Merchandizing Server and Dazzle

Citrix Receiver for Windows, Receiver for Mac, and Merchandising Server are components of the Citrix Delivery Center solution. While Citrix Delivery Center provides the application delivery infrastructure to the IT administrator, Citrix Merchandising Server and Citrix Receiver for Windows work together to streamline the installation and management of application delivery to the user desktops. Merchandising Server provides the administrative interface for configuring, delivering, and upgrading plug-ins for your users' computers.

Merchandizing Server

Dazzle provides users with self-service access to the applications and desktops they need to work productively. Icons for those applications and desktops can be presented on the local desktop, on the Dock, or in the Dazzle folder available from the Finder.

The new, easy-to-use interface allows users to subscribe to applications and desktops hosted on XenApp 6 and XenDesktop servers with a single click, replacing the need for individual connection files used by earlier versions of the plug-in.

1.6. HDX MediaStream for Flash

HDX MediaStream for Flash is an amazing feature of XenApp. It crept into XenApp 5 in the second and third feature packs and is installed by default in XenApp 6.

Essentially it offloads the processing of Flash content from the server to the client when using a Citrix distributed copy of Internet Explorer. The result is that the playback on the client PC is noticeably better than without it in most cases. It also hammers the CPU of the client PC instead of the CPU on the server so should improve the user experience for everyone else too and help get more users per server.

Despite being installed by default in modern clients and on XenApp 6 servers there are a few things that might trip it up. If any of these occur the client will generally silently fall back on the standard way of processing Flash content on the server.

1.7. Provisioning Server Technology

Provisioning Server technology allows Citrix administrators to create a single master virtual disk (vDisk) and then connect multiple desktops or servers to that vDisk and boot simultaneously.

Provisioning Server
With XenApp, we can leverage this technology to keep all of the Application Servers in a Citrix Farm consistent with the same applications, hotfixes, and patches. This ensures that users receive the same experience, regardless of which server they are load-balanced to. With this technology, administrators can now update many servers by updating a single vDisk, making administering large server farms much simpler.

1.8. Farm Properties Transformed into Citrix Policies

Till XenApp 5 Farm Properties were the only means by which all the settings on the Farm level was controlled of. From XenApp6 onwards there is no concept of Farm Properties. Everything is integrated in the Citrix Policy now. Citrix Policies have been made more compact and robust. With the help of Citrix Policies each and every settings at the Farm level can be controlled and modified. This new feature has made the life easier for the Citrix Administrators.

Virtualization

Definition: Virtualization cannot be defined clearly without a proper example as it is a concept and not a process. In brief, it can be said that Virtualization, in computing world, means a creation of a Virtual version of something, be it a Hardware device, an operating system, a network resource or an application.

Example: Suppose a computer is running on Windows XP and VMware Workstation is installed on it. With VMware three new Virtual Machines (VMs) could be set up on that Windows XP machine and each one of them can behave like an independent system.
One VM can run on Linux Operating System, one on Windows Server 2003 and the other one in Macintosh. So, three completely different Operating systems running on a single parent Operating System, i.e. Windows XP.

Types of Virtualization

There are various kinds of Virtualization that can be done in our technical arena. Lets discuss a few among them.

i) Server Virtualization: Server Virtualization is the concept where the resources of the Physical Server are masqueraded in front of the Users. Here there prevails a concept of Host and Guest. The Host is the original Physical Server with the base operating system and the Guests are the Virtual machines that are built on Top of it. It is also possible to mask the original resources present in the physical Server and allocate only the amount required to each the Virtual Machines. So when the Users logs into the Virtual machines they can only view the selected amount of resources allocated to it. It is also possible to allocate additional resources at any point of time to the Virtual Machines. So, the Server (Virtual Machines) that the Users are using and working on are hosted on another Physical Server. So, actually the users are on a virtual Server rather than on a Physical machine.
Example: XenServer, VMWare Workstation

ii) Desktop Virtualization: Desktop Virtualization is a concept where the personal desktop computing model has been enhanced to client-server architecture. Virtual Desktop Interface or the Virtual Desktop Infrastructure is the Server-Computing Model which allows the Virtualization of the Desktop model. It allows the users with different network subscribers to use the Virtual Machines and maintain an individualized central computer or Server. It can be located at any Residence, Data center or in a Server Room of any office Campus. The Users are located at different parts of the World but they will be using that same Computer (Desktop) by using a network connection be it LAN or WAN or a simple internet cloud.
Example: XenDesktop

iii) Application Virtualization: Application Virtualization is a concept which increases the portability of Heavyweight applications among all the Users who are located geographically at different corners of the globe. Let’s think of a situation where a user is out of his home and needs to prepare a PowerPoint presentation at that very moment. He can easily find a Cyber café or Cyber zone which may also not have the required software installed on the machine, he can easily login to a server which has the required software for him and he can complete his task successfully. May be that Server is Located at Los Angeles and he is sitting in Melbourne. So, if he has his Credentials he can easily use any of the applications that are hosted from the remote Servers.
Example: Citrix Presentation Server 4.5, XenApp5 and XenApp6.

iv) Memory Virtualization: Memory Virtualization is the concept to detach the volatile memory i.e. the Random Access Memory (RAM) of the individual computers present within a Cluster or Network and build a Memory pool with it. The advantage of the concept is that by doing this each machine within that cluster or network can use the memory from the pool. So, the memory utilization is now streamlined and the memory availability becomes more. A single machine can use the required amount of memory only and the spare memory of that machine can be used by other users ho really require it.

Buying Chinese tablet online.

Chinese gadgets have a great market India. The reason is that the Indian market is so concerned about the price of a product more than the quality they offer (And this is one of the reasons for many companies to care less about our market). And for this reason, most of us are attracted towards the cheap Chinese tablets which are available for even $100. I've purchased a 7" inch Apad Tablet touch screen. I have already tested some of their media players, phones and other such gadgets.

Build quality and performance

I've already said that the Indian market is too much 'price concerned'. May be this needs a little explanation, we usually buy products by considering the price to performance ratio rather than just the price. And I think this is one of the reasons I bought that 7" Apad. This one comes with Wi-Fi, Android OS, front camera, multiple format compatibility, 2 GB internal memory, Gravity Sensor, motion sensor and tons of other awesome features and all for just $100. I've been using it for a while and I should say it's really good for its price. Well, I should also say that the gravity sensor and motion sensor are not worth, it's just there and here's no much use of it since it's surprisingly slow . You should buy stuff from a reliable online store (e.g. DealExtreme.com ) because they're ready to ship you a new item if you receive a non-working one, which often happens with Chinese gadgets.

Now if we discuss about the cons of the build quality there are, of course, a lot of it. First of all, the 7" resistive touch screen is not so responsive for most of the times. Unlike on iPad, Galaxy tab or any other branded tablet you would have to tap on screen a couple of times to open what you want - but we can't expect more for the price. Also most of the tablets comes with built in batteries and there is no way to access the internal hardware. That means, if there is a battery complaint or a very silly internal hardware error your tablet stops working there is not much you can do about it other than putting it away.

Also, don't buy tablets just because it looks good in online pictures. Always do some Google searches on the model no. (if any!) and look at the user reviews and their videos. User videos gives you a quick idea about the tablet. This is important because when you buy cheap Chinese gadget it's better to follow the crowd or you'll be sorry for that. I'm saying this because one of my friends had such an experience. He bought a tablet which looked great. It has no user reviews or ratings. Even in the discussion board some users said that the tablet was not worth compared to other ones. Yet he bought this one and after one month the tablet stopped working. And a $100 was wasted on the tablet.

Follow the instructions in the manual as it is if you want your tablet to last for a while. If you don't follow the instructions carefully your tablet's life span will be much shorter than you imagine.

Some tablets comes with Chinese manual alone which makes it very difficult for the users from outside to learn different function of the tablet.

While importing via Postal

I bought my tablet from DealExtreme via Postal service and I had some problems. The Customs department blocked my product and I had to pay Rs. 1600 to get my product. It's some issue with sending electronic gadget via Postal, at least that's what the guy there said to me. However, the notice I've received mentioned that there should be an import license to purchase any item from another country if it costs more than Rs. 5000.

As a final word, don't buy Chinese tablets if you want it to use frequently like your laptop. It would take you several hours of punching on the screen to complete an email. Also you can't be sure whether it will last for even a year. You also don't have any worthy guarantees on the product . And it may not be even repairable. So if you're looking for some good tablets then don't go for these cheap ones.

It is beyond one's doubt that day by day we are advancing towards modernisation and along with it new developments in the fields of techniques and technologies are also taking effect. We welcome this advancement as this makes our lives easier compared to what it was before. Our young generation accepting this advancements in the different technical fields and are very happy to live and learn with these changes as it makes their lives more enjoyable and worth living.

It is worthwhile to mention in this context that the bar code system has arrived very long ago in our world and during those days it was found written on the body of foreign products or item goods. Today we find barcode prints in almost every products and it is beyond one's doubt that in future too this will be widely used by us. Bar code prints are generally marked by thick and thin lines on the cover of the products and under these lines some numerical are written.

Today we find bar code prints not only in foreign products items but also in our own Indian products like on wheat packets, sauce bottles, tooth paste cover, salt packets and on boxes of clothes, shoes, medicines etc. Today bar-coding has become compulsory because without it the different items and durables might not find a place in big malls and shopping centres of our country. Bar coding system is such a system with the help of which different information relating to a product is available along with its price, manufacturing date and serial number by just looking at the vertical lines at the backside of a particular product. The bar coding prints are in the computer readable format and with the help of a bar coding reader an operator could very easily find out the price and weight of the product by just focusing some light from the bar code reader.

In a bar code we generally see a combination of some thick and thin lines. The fact is that within these codes lies the data of the product. Generally barcode readers comes with a software which helps in reading bar codes. A data base system works in the background and are built with a software named "Access" which has a fonding and an interface. It also helps to recognize numbers related with the bar codes.

Now-a-days, companies prints the bar codes on the packets of its different products and to read these bar codes different types of barcode readers are available in the market. More often then not, stickers in the form of bar codes are stuck on the packet cover of different products. Through barcode printout barcode printer it is printed in the sticker format.

To tell you the truth, bar codes are even found printed on wine bottles, televisions, DVDs, Almira, blankets, bedsheets and in cosmetics like powder, nail polish etc. A common man doesn't understand anything by just looking at the bar codes. To read bar codes you need a barcode reader. A scanner is there inside the barcode reader together with a software and when light emits from the barcode reader, its light falls on the bar codes. The thick bars of the bar codes absorb more lights and reflects less and the whole process results in displaying all the details of a particular products. When light passes through a scanner there is also a photo sensor. The reflected rays from the barcode fall on the sensor and as a result an electrical signal is created. Now this electrical signal pass through a type of hardware and software and the software decodes it to break it to present the main data in front of us. For instance, quite often you might have seen in a shopping mall that as soon as a bar coder operator flashes light on the bar codes of a particular product its detail flashes on the computer screen.

So with the use of barcode readers different types of it are available in the market starting from Rs 600 to Rs 2000 to even Rs 5000. According to its shape and sizes and its functions different types of barcode readers are available in the market. Among them Wand type reader and gun type readers are very famous. These two types of readers are mostly used in shopping malls and are basically handheld types.

Types of Readers or Scanners

Wand type reader

This type of readers are a bit taller length wise and they resemble to a torch or a pen. It is swiped against the bar codes by holding it in our hands similarly as we do with a mouse. Now-a-days powerful wand readers could focus or reflect light from a distance.

Gun type reader

Yes, this type of reader looks more or less like a gun as the name suggests and this is largely being used in shopping malls by the shopping sales person. Basically this type of reader is used by aiming the bar codes and as soon as the trigger is pressed it emits a red or a green rays of light which gets reflected from the bar codes

Fixed type reader

This type of reader is more or less like that of a gun type of scanner but the difference lies in the fact that it remains stationary or fixed at a place. It depends upon the user to use this type of scanner or not because its usage is limited to a certain places only. But shopkeepers generally use this type of scanners and some are found at the check out point of the Super Markets and with other retailers.

It is worthwhile to mention here that with every reader there is a scanner with some type of specification. Wand type readers are available at a cheap price whereas fixed type readers are very powerful and expensive too. Wand type readers are required to be moved very often and hence might come up with technical errors and problems but now-a-days wand type readers are available in wide ranges and types and they work for a long time.

Gun type readers could scan even from a distance of one to two feet but in dusty conditions these readers doesn't work properly. In contrast to this fixed type of readers work very fast and it is capable of giving maximum output in very less time.

Generally we get data from readers which we need to decode in a methodical way. Most often the barcode readers doesn't come along with a decoder and one needs to purchase it separately because the output which we get from the barcode readers are not only used in computers but also in different industrial and consumer durables. Normally a computer hardware interface connects with barcode readers and decodes in two ways namely through serial ports or keyboard ports but now-a-days UCB boards are mostly used for the purpose.

In conclusion, to tell you the truth, barcode readers are very useful to us and its mere application makes things more easier and simpler for us and that's why it is considered as a boon in terms of shopping, marketing and billing sectors. Gun type readers are used in all shopping malls and by retailers and for future we can only hope that its usage and popularity will always be at the pick

Data Transmission:

Data transmission is the movement of data from one place to another using some form of representation appropriate to the transmission medium within a network, Data Transmission system caninclude electrical signals carried along a conductor, optical signalscarried along an optical fiber and electromagnetic waves, e.g. radio,or infrared signals transmitted through space.

Internal Data Transmission:

Internal Data Transmission refers to the data within a computer,between its different operational units e.g., between CPU andmemory. This takes place through internal data paths known asBuses.

External Data Transmission:

External Data Transmission refers to the transfer of data toeither local equipment (e.g. printers) or remote computers.

Here are some of the types of data transmission.

Analog Transmission: Analog Transmission has dominated all communication for thelast few decades. In analog transmission, signals are transmitted byvarying one of the physical characteristics continuously as a functionof time.Normally, continuously varying voltage is used for such atransmission (e.g. telephone line).Analog Transmission is generally used for the transmission ofvoice signals or TV signals, In terms of voltage, voice can be representedas follows

Digital Transmission:

In digital (binary) transmission the strings of 0,s and 1's aretransmitted. These bit streams consist of data, which might consist ofcharacters or numbers digitally, e.g., equivalent of 25 can be representedas 11001. This binary bit string can then be transmitted.

Communication Channel:

• Narrow bands handle low data volume. Data transmission ratesare from 45 to 300 baud. The low speed devices might usenarrow band communication.

• Voice bands handles moderate data transmission volumebetween 300 and 9600 baud. They are used for applicationranging from operating CRT to running a line printer. Theremajor application is for telephone voice communication, hencethe term voice band.

• Broadband handles very large volume of data. These systemsprovide data transmission rates of 1 million bytes or more.High-speed data analysis and satellite communication areexamples of broadband communication system.

Simplex, Half-duplex, Communication:

The direction in which information can flow over a transmissionpath is determined by the properties of both the transmitting and thereceiving devices. There are three basic options.

In Simplex mode, the communication channel is used in onedirection. The receiver receives the signals from the transmittingdevice. A typical use is to gather data from a monitoring device at aregular interval. The simplex mode is rarely used for data communication

In Half-duplex mode, the communication channel is used inboth directions, but only in one direction at a time. This requires thereceiving and transmitting devices to switch between sent andreceive modes after each transmission. The analogous example ofthis mode is the old wireless system (walkie-talkie), which is used ineither transmit mode or receive mode.

Parallel Transmission:

In parallel data transmission, there are multiple parallel linesconnecting the transmitting and receiving units.Each wire carries a bit of information. Normally, one characteris transferred in one go.

Serial Transmission:

In serial data transmission, each bit is sent sequentially oneafter another and it requires only one pair of wire conductors forconnecting the receiving and transmitting units.Serial transmission is slower than parallel transmission, whichis used primarily for transferring data between devices at the samesite; most common example is Personal Computer to Printer. Communicationb between computers is almost always serial.

Communication protocols/ Standard:

There are several manufacturers of computer hardware andsoftware across the, globe. For successful data communication theseproducts should be compatibles with each other or they should compatiblewith each other or they should conform to certain set of rulesso that any one can use them. These sets of rules are known ascommunication protocols or communication standards.

In other words, protocols are technical customs or guides thatgovern the exchange of signal transmission and reception betweenequipment.

Some of the functions that communication protocol regulates are:

•Control of information transfer

• Structure and formats of data

• Error recoveries• Re-transmission control

• Interface management-only communication devices using sameprotocols can communicate with each other.

• To make sure that the bits (or characters) are transmittedthrough the channel or line, we need a link level protocolbetween two computers.

Synchronous transmission:

The mode of transmission is the way in which coded charactersare assembled for the process of transmission and permits thereceiving devices to” identify where the coding for each characterbegins and ends within the torrent of bits. When two computerscommunicate, they must have a way to synchronize the flow of dataso that the receiving computer can read at the same speed at whichthe sending computer transmits.

Asynchronous Transmission:

In asynchronous transmission, each character is transmittedseparately, that is, one character at a time. Each character beginswith a start bit, which tells the receiving device where the charactercoding begins and ends with a stop bit, which tells the receivingdevice where the character coding ends. Then, the next character issent, with start and stops bits. The start and stop bits and the intervalof time between consecutive characters allow the receiving andsending computers to synchronize the transmission. The parity bit isused for error checking while transmission of data.

Wide Area Network:

A WAN spans a large geographic area, such as a state,province or country.WANs often connect multiple smaller networks, such as localarea networks (LANs) or metro area networks (MANs)

The world's most popular WAN is the Internet. Some segmentsof the Internet, like VPN-based extranets, are also WANs inthemselves. Finally, many WANs are corporate or research networksthat utilize leased lines.

Subnet is a logical grouping of connected network devices.Nodes on a subnet tend to be located in close physical proximity toeach other on a LAN.

Network designers employ subnets as a way to partitionnetworks into logical segments for greater ease of administration.When subnets are properly implemented, both the performance andsecurity of networks can be improved.

Subcategories

Hardware & Troubleshooting

Software

PC & Internet Security

New Technologies

Web Hosting

Web Hosting is a service offered by web hosting providers to the individuals and organizations to make their websites accessible on the internet. Depending on the requirement, one can avail different types of web hosting such as shared hosting, dedicated hosting, virtual private hosting, cloud hosting etc.

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New Features of XenApp 6