In computer science, the kernel is the central component of most computer operating systems (OS). Its responsibilities include managing the system's resources (the communication between hardware and software components).[1] As a basic component of an operating system, a kernel provides the lowest-level abstraction layer for the resources (especially memory, processors and I/O devices) that application software must control to perform its function. It typically makes these facilities available to application processes through inter-process communication mechanisms and system calls.
These tasks are done differently by different kernels, depending on their design and implementation. While monolithic kernels will try to achieve these goals by executing all the code in the same address space to increase the performance of the system, microkernels run most of their services in user space, aiming to improve maintainability and modularity of the codebase.[2] A range of possibilities exists between these two extremes.
Friday, June 27, 2008
Why are Linux and Mac OS X safer?
Why are Linux and Mac OS X safer?
First, look at the two factors that cause email viruses and worms to propagate: social engineering, and poorly designed software. Social engineering is the art of conning someone into doing something they shouldn't do, or revealing something that should be kept secret. Virus writers use social engineering to convince people to do stupid things, like open attachments that carry viruses and worms. Poorly designed software makes it easier for social engineering to take place, but such software can also subvert the efforts of a knowledgable, security-minded individual or organization. Together, the two factors can turn a single virus incident into a widespread disaster.
Let's look further at social engineering. Windows software is either executable or not, depending on the file extension. So if a file ends with ".exe" or ".scr", it can be run as a program (yes, of course, if you change a text file's extension from ".txt" to ".exe", nothing will happen, because it's not magically an executable; I'm talking about real executable programs). It's easy to run executables in the Windows world, and users who get an email with a subject line like "Check out this wicked screensaver!" and an attachment, too often click on it without thinking first, and bang! we're off to the races and a new worm has taken over their systems.
Even worse, Microsoft's email software is able to infect a user's computer when they do something as innocuous as read an email! Don't believe me? Take a look at Microsoft Security Bulletins MS99-032, MS00-043, MS01-015, MS01-020, MS02-068, or MS03-023, for instance. Notice that's at least one for the last five years. And though Microsoft's latest versions of Outlook block most executable attachments by default, it's still possible to override those protections.
This sort of social engineering, so easy to accomplish in Windows, requires far more steps and far greater effort on the part of the Linux user. Instead of just reading an email (... just reading an email?!?), a Linux user would have to read the email, save the attachment, give the attachment executable permissions, and then run the executable. Even as less sophisticated users begin to migrate to Linux, they may not understand exactly why they can't just execute attachments, but they will still have to go through the steps. As Martha Stewart would say, this is a good thing. Further, due to the strong community around Linux, new users will receive education and encouragement in areas such as email security that are currently lacking in the Windows world, which should help to alleviate any concerns on the part of newbies.
Further, due to the strong separation between normal users and the privileged root user, our Linux user would have to be running as root to really do any damage to the system. He could damage his /home directory, but that's about it. So the above steps now become the following: read, save, become root, give executable permissions, run. The more steps, the less likely a virus infection becomes, and certainly the less likely a catastrophically spreading virus becomes. And since Linux users are taught from the get-go to never run as root, and since Mac OS X doesn't even allow users to use the root account unless they first enable the option, it's obvious the likelihood of email-driven viruses and worms lessens on those platforms.
Unfortunately, running as root (or Administrator) is common in the Windows world. In fact, Microsoft is still engaging in this risky behavior. Windows XP, supposed Microsoft's most secure desktop operating system, automatically makes the first named user of the system an Administrator, with the power to do anything he wants to the computer. The reasons for this decision boggle the mind. With all the lost money and productivity over the last decade caused by countless Microsoft-borne viruses and worms, you'd think the company could have changed its procedures in this area, but no.
Even if the OS has been set up correctly, with an Administrator account and a non-privileged user account, things are still not copasetic. On a Windows system, programs installed by a non-Administrative user can still add DLLs and other system files that can be run at a level of permission that damages the system itself. Even worse, the collection of files on a Windows system - the operating system, the applications, and the user data - can't be kept apart from each other. Things are intermingled to a degree that makes it unlikely that they will ever be satisfactorily sorted out in any sensibly secure fashion.
The final reason why social engineering is easier in the Windows world is also an illustration of the dangers inherent in any monoculture, whether biological or technological. In the same way that genetic diversity in a population of living creatures is desirable because it reduces the likelihood that an illness - like a virus - will utterly wipe out every animal or plant, diversity in computing environments helps to protect the users of those devices.
Linux runs on many architectures, not just Intel, and there are many versions of Linux, many packaging systems, and many shells. But most obvious to the end user, Linux mail clients and address books are far from standardized. KMail, Mozilla Mail, Evolution, pine, mutt, emacs ... the list goes on. It's simply not like the Windows world, in which Microsoft's email programs - Outlook and Outlook Express - dominate. In the Windows world, a virus writer knows how the monoculture operates, so he can target his virus, secure in the knowledge that millions of systems have the same vulnerability. A virus targeted to a specific vulnerability in Evolution, on the other hand, might affect some people, but not everyone using Linux. The growth of the Microsoft monoculture in computing is a dangerous thing for users of Microsoft products, but also for all computing users, who suffer the consequences of disasters in that environment, such as wasted network resources, dangers to national security, and lost productivity (note: the link is to a 880 kb PDF file).
Now that we've looked at the social engineering side of things, let's examine software design for reasons why Linux (and Mac OS X) is better designed than Microsoft when it comes to email security. Microsoft continually links together its software, often not for technical reasons, but instead for marketing or business development reasons (see the previous link for corroboration). For instance, Outlook Express and Outlook both use the consistently-buggy Internet Explorer to view HTML-based emails. As a result, a hole in IE affects OE. Linux email readers don't indulge in such behavior, with two exceptions: Mozilla Mail uses the Gecko engine that powers Mozilla to view HTML-based email, while KMail relies on the KHTML engine that the Konqueror browser uses. Fortunately, both Mozilla and the KDE Project have excellent records when it comes to security.
Further, the email programs themselves are designed to act in a more secure manner. The default behavior of the email program I prefer - KMail - is to not load external references in messages, such as pictures and Web bugs, and to not display HTML. When an HTML-based email shows up in my Inbox, I see only the HTML code, and a message appears at the top of the email: "This is an HTML message. For security reasons, only the raw HTML code is shown. If you trust the sender of this message then you can activate formatted HTML display for this message by clicking here." But even after I activate the HTML, certain dynamic elements that can be introduced in an HTML-based email - like Java, Javascript, plugins and even the "refresh" META tag - do not display, and cannot even be enabled in KMail.
Finally, if there is an attachment, it does not automatically run ... ever. Instead, I have to click it, and when I do, I get a dialog box offering me three options: "Save As ..." (the default), "Open With ...", and "Cancel". If I have mapped a file type to a specific program - for instance, I have associated PDFs with the PS/PDF Viewer, then "Open With ..." instead says "Open", and if I choose "Open", then the file opens in the PS/PDF Viewer. However, in either case, the dialog box always contains a warning advising the user that attachments can compromise security. This is all good, very good.
For all these reasons, even if a few individuals got infected with a virus due to extremely foolish behavior, it's unlikely the virus would spread to other machines. Unlike Sobig.F, which is the fastest spreading virus ever, a Linux-based Virus would fizzle out quickly. Windows is an inviting petri dish for viruses and worms, while Linux is a hostile environment for such nasties.
First, look at the two factors that cause email viruses and worms to propagate: social engineering, and poorly designed software. Social engineering is the art of conning someone into doing something they shouldn't do, or revealing something that should be kept secret. Virus writers use social engineering to convince people to do stupid things, like open attachments that carry viruses and worms. Poorly designed software makes it easier for social engineering to take place, but such software can also subvert the efforts of a knowledgable, security-minded individual or organization. Together, the two factors can turn a single virus incident into a widespread disaster.
Let's look further at social engineering. Windows software is either executable or not, depending on the file extension. So if a file ends with ".exe" or ".scr", it can be run as a program (yes, of course, if you change a text file's extension from ".txt" to ".exe", nothing will happen, because it's not magically an executable; I'm talking about real executable programs). It's easy to run executables in the Windows world, and users who get an email with a subject line like "Check out this wicked screensaver!" and an attachment, too often click on it without thinking first, and bang! we're off to the races and a new worm has taken over their systems.
Even worse, Microsoft's email software is able to infect a user's computer when they do something as innocuous as read an email! Don't believe me? Take a look at Microsoft Security Bulletins MS99-032, MS00-043, MS01-015, MS01-020, MS02-068, or MS03-023, for instance. Notice that's at least one for the last five years. And though Microsoft's latest versions of Outlook block most executable attachments by default, it's still possible to override those protections.
This sort of social engineering, so easy to accomplish in Windows, requires far more steps and far greater effort on the part of the Linux user. Instead of just reading an email (... just reading an email?!?), a Linux user would have to read the email, save the attachment, give the attachment executable permissions, and then run the executable. Even as less sophisticated users begin to migrate to Linux, they may not understand exactly why they can't just execute attachments, but they will still have to go through the steps. As Martha Stewart would say, this is a good thing. Further, due to the strong community around Linux, new users will receive education and encouragement in areas such as email security that are currently lacking in the Windows world, which should help to alleviate any concerns on the part of newbies.
Further, due to the strong separation between normal users and the privileged root user, our Linux user would have to be running as root to really do any damage to the system. He could damage his /home directory, but that's about it. So the above steps now become the following: read, save, become root, give executable permissions, run. The more steps, the less likely a virus infection becomes, and certainly the less likely a catastrophically spreading virus becomes. And since Linux users are taught from the get-go to never run as root, and since Mac OS X doesn't even allow users to use the root account unless they first enable the option, it's obvious the likelihood of email-driven viruses and worms lessens on those platforms.
Unfortunately, running as root (or Administrator) is common in the Windows world. In fact, Microsoft is still engaging in this risky behavior. Windows XP, supposed Microsoft's most secure desktop operating system, automatically makes the first named user of the system an Administrator, with the power to do anything he wants to the computer. The reasons for this decision boggle the mind. With all the lost money and productivity over the last decade caused by countless Microsoft-borne viruses and worms, you'd think the company could have changed its procedures in this area, but no.
Even if the OS has been set up correctly, with an Administrator account and a non-privileged user account, things are still not copasetic. On a Windows system, programs installed by a non-Administrative user can still add DLLs and other system files that can be run at a level of permission that damages the system itself. Even worse, the collection of files on a Windows system - the operating system, the applications, and the user data - can't be kept apart from each other. Things are intermingled to a degree that makes it unlikely that they will ever be satisfactorily sorted out in any sensibly secure fashion.
The final reason why social engineering is easier in the Windows world is also an illustration of the dangers inherent in any monoculture, whether biological or technological. In the same way that genetic diversity in a population of living creatures is desirable because it reduces the likelihood that an illness - like a virus - will utterly wipe out every animal or plant, diversity in computing environments helps to protect the users of those devices.
Linux runs on many architectures, not just Intel, and there are many versions of Linux, many packaging systems, and many shells. But most obvious to the end user, Linux mail clients and address books are far from standardized. KMail, Mozilla Mail, Evolution, pine, mutt, emacs ... the list goes on. It's simply not like the Windows world, in which Microsoft's email programs - Outlook and Outlook Express - dominate. In the Windows world, a virus writer knows how the monoculture operates, so he can target his virus, secure in the knowledge that millions of systems have the same vulnerability. A virus targeted to a specific vulnerability in Evolution, on the other hand, might affect some people, but not everyone using Linux. The growth of the Microsoft monoculture in computing is a dangerous thing for users of Microsoft products, but also for all computing users, who suffer the consequences of disasters in that environment, such as wasted network resources, dangers to national security, and lost productivity (note: the link is to a 880 kb PDF file).
Now that we've looked at the social engineering side of things, let's examine software design for reasons why Linux (and Mac OS X) is better designed than Microsoft when it comes to email security. Microsoft continually links together its software, often not for technical reasons, but instead for marketing or business development reasons (see the previous link for corroboration). For instance, Outlook Express and Outlook both use the consistently-buggy Internet Explorer to view HTML-based emails. As a result, a hole in IE affects OE. Linux email readers don't indulge in such behavior, with two exceptions: Mozilla Mail uses the Gecko engine that powers Mozilla to view HTML-based email, while KMail relies on the KHTML engine that the Konqueror browser uses. Fortunately, both Mozilla and the KDE Project have excellent records when it comes to security.
Further, the email programs themselves are designed to act in a more secure manner. The default behavior of the email program I prefer - KMail - is to not load external references in messages, such as pictures and Web bugs, and to not display HTML. When an HTML-based email shows up in my Inbox, I see only the HTML code, and a message appears at the top of the email: "This is an HTML message. For security reasons, only the raw HTML code is shown. If you trust the sender of this message then you can activate formatted HTML display for this message by clicking here." But even after I activate the HTML, certain dynamic elements that can be introduced in an HTML-based email - like Java, Javascript, plugins and even the "refresh" META tag - do not display, and cannot even be enabled in KMail.
Finally, if there is an attachment, it does not automatically run ... ever. Instead, I have to click it, and when I do, I get a dialog box offering me three options: "Save As ..." (the default), "Open With ...", and "Cancel". If I have mapped a file type to a specific program - for instance, I have associated PDFs with the PS/PDF Viewer, then "Open With ..." instead says "Open", and if I choose "Open", then the file opens in the PS/PDF Viewer. However, in either case, the dialog box always contains a warning advising the user that attachments can compromise security. This is all good, very good.
For all these reasons, even if a few individuals got infected with a virus due to extremely foolish behavior, it's unlikely the virus would spread to other machines. Unlike Sobig.F, which is the fastest spreading virus ever, a Linux-based Virus would fizzle out quickly. Windows is an inviting petri dish for viruses and worms, while Linux is a hostile environment for such nasties.
.EXE
EXE is the common filename extension denoting an executable file (a program) in the DOS, OpenVMS, Microsoft Windows, ReactOS, and OS/2 operating systems. Besides the executable program itself, many EXE files contain other components called resources, such as bitmaps and icons which the executable program may use for its graphical user interfac
.htaccess
IN the Apache web server, .htaccess (hypertext access) is the default name of directory-level configuration files. A .htaccess file is placed in a particular directory, and the directives in the .htaccess file apply to that directory, and all subdirectories thereof. It provides the ability to customize configuration for requests to the particular directory. The file name starts with a dot because dot-files are by convention hidden files on Unix-like operating systems.
* Authorization, authentication: .htaccess files are often used to specify the security restrictions for the particular directory, hence the filename "access". The .htaccess file is often accompanied by an .htpasswd file which stores valid usernames and their passwords.
* Customized error responses: Changing the page that is shown when a server-side error occurs, for example HTTP 404 Not Found.
* Rewriting URLs: Servers often use .htaccess to rewrite "ugly" URLs to shorter and prettier ones.
* Cache Control: .htaccess files allow a server to control User agent caching used by web browsers to reduce bandwidth usage, server load, and perceived lag.
When .htaccess files should be used
For servers with multiple users, as is common in shared web hosting plans, it is often desirable to allow individual users the ability to alter their site configuration. In general, .htaccess files should be used by users who do not have access to the main server configuration files.
When .htaccess files should not be used
To control Apache, using the main server configuration file httpd.conf[2] is preferred for security and performance reasons.[3]
1. Performance loss - for each HTTP request there are additional file-system accesses for every parent directory when using .htaccess
2. Security - allowing individual users to modify the configuration of a server can cause security concerns if not set up properly.
* Authorization, authentication: .htaccess files are often used to specify the security restrictions for the particular directory, hence the filename "access". The .htaccess file is often accompanied by an .htpasswd file which stores valid usernames and their passwords.
* Customized error responses: Changing the page that is shown when a server-side error occurs, for example HTTP 404 Not Found.
* Rewriting URLs: Servers often use .htaccess to rewrite "ugly" URLs to shorter and prettier ones.
* Cache Control: .htaccess files allow a server to control User agent caching used by web browsers to reduce bandwidth usage, server load, and perceived lag.
When .htaccess files should be used
For servers with multiple users, as is common in shared web hosting plans, it is often desirable to allow individual users the ability to alter their site configuration. In general, .htaccess files should be used by users who do not have access to the main server configuration files.
When .htaccess files should not be used
To control Apache, using the main server configuration file httpd.conf[2] is preferred for security and performance reasons.[3]
1. Performance loss - for each HTTP request there are additional file-system accesses for every parent directory when using .htaccess
2. Security - allowing individual users to modify the configuration of a server can cause security concerns if not set up properly.
PROCRASTINATION.......................
v.intr.
To put off doing something, especially out of habitual carelessness or laziness.
v.tr.
To postpone or delay needlessly.
To put off doing something, especially out of habitual carelessness or laziness.
v.tr.
To postpone or delay needlessly.
Thursday, June 26, 2008
WML
What is WML?
WML stands for Wireless Markup Language. It is a mark-up language inherited from HTML, but WML is based on XML, so it is much stricter than HTML.
WML is used to create pages that can be displayed in a WAP browser. Pages in WML are called DECKS. Decks are constructed as a set of CARDS.
Examples of WAP use
* Checking train table information
* Ticket purchase
* Flight check in
* Viewing traffic information
* Checking weather conditions
* Looking up stock values
* Looking up phone numbers
* Looking up addresses
* Looking up sport results
What is WMLScript?
WML uses WMLScript to run simple code on the client. WMLScript is a light JavaScript language. However, WML scripts are not embedded in the WML pages. WML pages only contains references to script URLs. WML scripts need to be compiled into byte code on a server before they can run in a WAP browser.
WAP Homepages
WAP homepages are not very different from HTML homepages. The markup language used for WAP is WML (Wireless Markup Language). WML uses tags - just like HTML - but the syntax is stricter and conforms to the XML 1.0 standard.
WML pages have the extension *.WML, just like HTML pages have the extension *.HTML.
The Wireless Application Protocol (WAP) Forum
developed the de-facto world standard for wireless information and telephony services on digital mobile phones and other wireless terminals. The WAP Forum published an open, global wireless protocol specification based on existing Internet standards, such as XML and IP, for all wireless networks.
The WAP Forum has consolidated into the Open Mobile Alliance (OMA) and does no longer exists as an independent organization.
The specification work from WAP continues within OMA and can be found at:
http://www.openmobilealliance.org/tech/affiliates/wap/wapindex.html
WAP Company
Symbian
Symbian was established as a private independent company in June 1998 and is owned by Ericsson, Nokia, Matsushita (Panasonic), Motorola, Psion, Siemens and Sony Ericsson. Symbian supplies the advanced, open, standard operating system - Symbian OS - for data-enabled mobile phones.
WML stands for Wireless Markup Language. It is a mark-up language inherited from HTML, but WML is based on XML, so it is much stricter than HTML.
WML is used to create pages that can be displayed in a WAP browser. Pages in WML are called DECKS. Decks are constructed as a set of CARDS.
Examples of WAP use
* Checking train table information
* Ticket purchase
* Flight check in
* Viewing traffic information
* Checking weather conditions
* Looking up stock values
* Looking up phone numbers
* Looking up addresses
* Looking up sport results
What is WMLScript?
WML uses WMLScript to run simple code on the client. WMLScript is a light JavaScript language. However, WML scripts are not embedded in the WML pages. WML pages only contains references to script URLs. WML scripts need to be compiled into byte code on a server before they can run in a WAP browser.
WAP Homepages
WAP homepages are not very different from HTML homepages. The markup language used for WAP is WML (Wireless Markup Language). WML uses tags - just like HTML - but the syntax is stricter and conforms to the XML 1.0 standard.
WML pages have the extension *.WML, just like HTML pages have the extension *.HTML.
The Wireless Application Protocol (WAP) Forum
developed the de-facto world standard for wireless information and telephony services on digital mobile phones and other wireless terminals. The WAP Forum published an open, global wireless protocol specification based on existing Internet standards, such as XML and IP, for all wireless networks.
The WAP Forum has consolidated into the Open Mobile Alliance (OMA) and does no longer exists as an independent organization.
The specification work from WAP continues within OMA and can be found at:
http://www.openmobilealliance.org/tech/affiliates/wap/wapindex.html
WAP Company
Symbian
Symbian was established as a private independent company in June 1998 and is owned by Ericsson, Nokia, Matsushita (Panasonic), Motorola, Psion, Siemens and Sony Ericsson. Symbian supplies the advanced, open, standard operating system - Symbian OS - for data-enabled mobile phones.
Maintenance and evolutions
The WAP Forum has consolidated (along with many other forums of the industry) into OMA (Open Mobile Alliance), which covers virtually everything in future development of wireless data services.
WAP 2.0
WAP 2.0 is a re-engineering of WAP using a cut-down version of XHTML with end-to-end HTTP (i.e., dropping the gateway and custom protocol suite used to communicate with it). A WAP gateway can be used in conjunction with WAP 2.0; however, in this scenario, it is used as a standard proxy server. The WAP gateway's role would then shift from one of translation to adding additional information to each request. This would be configured by the operator and could include telephone numbers, location, billing information, and handset information.
XHTML Mobile Profile (XHTML MP), the markup language defined in WAP 2.0, is made to work in mobile devices. It is a subset of XHTML and a superset of XHTML Basic. A version of cascading style sheets (CSS) called WAP CSS is supported by XHTML MP.
WAP Push
WAP Push has been incorporated into the specification to allow WAP content to be pushed to the mobile handset with minimum user intervention. A WAP Push is basically a specially encoded message which includes a link to a WAP address. WAP Push is specified on top of WDP; as such, it can be delivered over any WDP-supported bearer, such as GPRS or SMS.
In most GSM networks there are a wide range of modified processors, however, GPRS activation from the network is not generally supported, so WAP Push messages have to be delivered on top of the SMS bearer. On receiving a WAP Push, a WAP 1.2 or later enabled handset will automatically give the user the option to access the WAP content. This is also known as WAP Push SI (Service Indication).
The network entity that processes WAP Pushes and delivers them over an IP or SMS Bearer is known as a Push Proxy Gateway.
PURPOSE OF WAP
To enable easy, fast delivery of relevant information and services to mobile users.
THE DEVICES WHICH WILL USE WAP
Handheld digital wireless devices such as mobile phones, pagers, two-way radios, smartphones, and communicators -- from low-end to high-end.
With minimal risk and investment, WAP enables operators to decrease churn, cut costs, and increase revenues by improving existing, value-added services and offering exciting new informational services.
Why are equipment manufacturers interested in WAP?
Being a global open specification suite, WAP has generated the critical mass for manufacturers. This has opened up new product and marketing opportunities in the wireless industry and provides new revenue to participating companies.
How does Bluetooth relate to WAP?
Bluetooth is a local area low power radio link between devices. Many of the usage scenarios for Bluetooth will also involve one of the devices communicating over the air using WAP. While many Bluetooth members are also WAP members, and it is expected that many future handheld wireless devices will deploy both Bluetooth and WAP technology, the two technologies fundamentally address different problems.
WAP IN THE FUTURE
Will WAP comply with Third Generation wireless standards?
Yes, WAP has been designed to be as independent as possible from the underlying network technology.
Is WAP necessary with higher bandwidth 3G networks?
Even as bandwidths increase, the cost of that bandwidth does not fall to zero. These costs result from higher power usage in the terminals, higher costs in the radio sections, greater use of RF spectrum, and increased network loading. In addition, the original constraints WAP was designed for -- intermittent coverage, small screens, low power consumption, wide scalability over bearers and devices, and one-handed operation -- are still valid in 3G networks. Finally, we can expect the bandwidth required by application users to steadily increase. Therefore, there is still a need to optimize the device and network resources for wireless environments. We can expect WAP to optimize support for multimedia applications that continue to be relevant. If WAP is very successful in mass-markets on 2.5G networks, 3G networks may be needed purely for capacity relief.
The WAP Forum has consolidated (along with many other forums of the industry) into OMA (Open Mobile Alliance), which covers virtually everything in future development of wireless data services.
WAP 2.0
WAP 2.0 is a re-engineering of WAP using a cut-down version of XHTML with end-to-end HTTP (i.e., dropping the gateway and custom protocol suite used to communicate with it). A WAP gateway can be used in conjunction with WAP 2.0; however, in this scenario, it is used as a standard proxy server. The WAP gateway's role would then shift from one of translation to adding additional information to each request. This would be configured by the operator and could include telephone numbers, location, billing information, and handset information.
XHTML Mobile Profile (XHTML MP), the markup language defined in WAP 2.0, is made to work in mobile devices. It is a subset of XHTML and a superset of XHTML Basic. A version of cascading style sheets (CSS) called WAP CSS is supported by XHTML MP.
WAP Push
WAP Push has been incorporated into the specification to allow WAP content to be pushed to the mobile handset with minimum user intervention. A WAP Push is basically a specially encoded message which includes a link to a WAP address. WAP Push is specified on top of WDP; as such, it can be delivered over any WDP-supported bearer, such as GPRS or SMS.
In most GSM networks there are a wide range of modified processors, however, GPRS activation from the network is not generally supported, so WAP Push messages have to be delivered on top of the SMS bearer. On receiving a WAP Push, a WAP 1.2 or later enabled handset will automatically give the user the option to access the WAP content. This is also known as WAP Push SI (Service Indication).
The network entity that processes WAP Pushes and delivers them over an IP or SMS Bearer is known as a Push Proxy Gateway.
PURPOSE OF WAP
To enable easy, fast delivery of relevant information and services to mobile users.
THE DEVICES WHICH WILL USE WAP
Handheld digital wireless devices such as mobile phones, pagers, two-way radios, smartphones, and communicators -- from low-end to high-end.
With minimal risk and investment, WAP enables operators to decrease churn, cut costs, and increase revenues by improving existing, value-added services and offering exciting new informational services.
Why are equipment manufacturers interested in WAP?
Being a global open specification suite, WAP has generated the critical mass for manufacturers. This has opened up new product and marketing opportunities in the wireless industry and provides new revenue to participating companies.
How does Bluetooth relate to WAP?
Bluetooth is a local area low power radio link between devices. Many of the usage scenarios for Bluetooth will also involve one of the devices communicating over the air using WAP. While many Bluetooth members are also WAP members, and it is expected that many future handheld wireless devices will deploy both Bluetooth and WAP technology, the two technologies fundamentally address different problems.
WAP IN THE FUTURE
Will WAP comply with Third Generation wireless standards?
Yes, WAP has been designed to be as independent as possible from the underlying network technology.
Is WAP necessary with higher bandwidth 3G networks?
Even as bandwidths increase, the cost of that bandwidth does not fall to zero. These costs result from higher power usage in the terminals, higher costs in the radio sections, greater use of RF spectrum, and increased network loading. In addition, the original constraints WAP was designed for -- intermittent coverage, small screens, low power consumption, wide scalability over bearers and devices, and one-handed operation -- are still valid in 3G networks. Finally, we can expect the bandwidth required by application users to steadily increase. Therefore, there is still a need to optimize the device and network resources for wireless environments. We can expect WAP to optimize support for multimedia applications that continue to be relevant. If WAP is very successful in mass-markets on 2.5G networks, 3G networks may be needed purely for capacity relief.
WAP
What is WAP?
The wireless industry came up with the idea of WAP. The point of this standard was to show internet contents on wireless clients, like mobile phones.
* WAP stands for Wireless Application Protocol
* WAP is an application communication protocol
* WAP is used to access services and information
* WAP is inherited from Internet standards
* WAP is for handheld devices such as mobile phones
* WAP is a protocol designed for micro browsers
* WAP enables the creating of web applications for mobile devices.
* WAP uses the mark-up language WML (not HTML)
* WML is defined as an XML 1.0 application
FIRSTLY LET WE KNOW WHAT IS A PROTOCOL
In computing, a protocol is a convention or standard that controls or enables the connection, communication, and data transfer between two computing endpoints. In its simplest form, a protocol can be defined as the rules governing the syntax, semantics, and synchronization of communication. Protocols may be implemented by hardware, software, or a combination of the two. At the lowest level, a protocol defines the behavior of a hardware connection.
The Wireless Application Protocol
The WAP protocol is the leading standard for information services on wireless terminals like digital mobile phones.
The WAP standard is based on Internet standards (HTML, XML and TCP/IP). It consists of a WML language specification, a WMLScript specification, and a Wireless Telephony Application Interface (WTAI) specification.
WAP is published by the WAP Forum, founded in 1997 by Ericsson, Motorola, Nokia, and Unwired Planet. Forum members now represent over 90% of the global handset market, as well as leading infrastructure providers, software developers and other organizations.
WAP Micro Browsers
To fit into a small wireless terminal, WAP uses a Micro Browser.
A Micro Browser is a small piece of software that makes minimal demands on hardware, memory and CPU. It can display information written in a restricted mark-up language called WML.
The Micro Browser can also interpret a reduced version of JavaScript called WMLScript.
The wireless industry came up with the idea of WAP. The point of this standard was to show internet contents on wireless clients, like mobile phones.
* WAP stands for Wireless Application Protocol
* WAP is an application communication protocol
* WAP is used to access services and information
* WAP is inherited from Internet standards
* WAP is for handheld devices such as mobile phones
* WAP is a protocol designed for micro browsers
* WAP enables the creating of web applications for mobile devices.
* WAP uses the mark-up language WML (not HTML)
* WML is defined as an XML 1.0 application
FIRSTLY LET WE KNOW WHAT IS A PROTOCOL
In computing, a protocol is a convention or standard that controls or enables the connection, communication, and data transfer between two computing endpoints. In its simplest form, a protocol can be defined as the rules governing the syntax, semantics, and synchronization of communication. Protocols may be implemented by hardware, software, or a combination of the two. At the lowest level, a protocol defines the behavior of a hardware connection.
The Wireless Application Protocol
The WAP protocol is the leading standard for information services on wireless terminals like digital mobile phones.
The WAP standard is based on Internet standards (HTML, XML and TCP/IP). It consists of a WML language specification, a WMLScript specification, and a Wireless Telephony Application Interface (WTAI) specification.
WAP is published by the WAP Forum, founded in 1997 by Ericsson, Motorola, Nokia, and Unwired Planet. Forum members now represent over 90% of the global handset market, as well as leading infrastructure providers, software developers and other organizations.
WAP Micro Browsers
To fit into a small wireless terminal, WAP uses a Micro Browser.
A Micro Browser is a small piece of software that makes minimal demands on hardware, memory and CPU. It can display information written in a restricted mark-up language called WML.
The Micro Browser can also interpret a reduced version of JavaScript called WMLScript.
Wednesday, June 25, 2008
GNUC
The GNU Compiler Collection (usually shortened to GCC) is a set of compilers produced for various programming languages by the GNU Project. GCC is a key component of the GNU toolchain. As well as being the official compiler of the GNU system, GCC has been adopted as the standard compiler by most other modern Unix-like computer operating systems, including Linux, the BSD family and Mac OS X. GCC has been ported to a wide variety of computer architectures, and is widely deployed as a tool in commercial, proprietary and closed source software development environments. GCC is also used in popular embedded platforms like Symbian[1], Playstation and Sega Dreamcast.[citation needed]
Originally named the GNU C Compiler, because it only handled the C programming language, GCC 1.0 was released in 1987, and the compiler was extended to compile C++ in December of that year.[2] Front ends were later developed for Fortran, Pascal, Objective C, Java, and Ada, among others.[3]
The Free Software Foundation (FSF) distributes GCC under the GNU General Public License (GNU GPL) and the GNU Lesser General Public License (GNU LGPL). GCC is free software.
Originally named the GNU C Compiler, because it only handled the C programming language, GCC 1.0 was released in 1987, and the compiler was extended to compile C++ in December of that year.[2] Front ends were later developed for Fortran, Pascal, Objective C, Java, and Ada, among others.[3]
The Free Software Foundation (FSF) distributes GCC under the GNU General Public License (GNU GPL) and the GNU Lesser General Public License (GNU LGPL). GCC is free software.
WHAT IS UML?
In the field of software engineering, the Unified/Universal Modeling Language (UML) is a standardized visual specification language for object modeling. UML is a general-purpose modeling language that includes a graphical notation used to create an abstract model of a system, referred to as a UML model.
UML is officially defined at the Object Management Group (OMG) by the UML metamodel, a Meta-Object Facility metamodel (MOF). Like other MOF-based specifications, UML has allowed software developers to concentrate more on design and architecture[citation needed].
UML models may be automatically transformed to other representations (e.g. Java) by means of QVT-like transformation languages, supported by the OMG.
UML is extensible, offering the following mechanisms for customization: profiles and stereotype. The semantics of extension by profiles have been improved with the UML 2.0 major revision.
UML is officially defined at the Object Management Group (OMG) by the UML metamodel, a Meta-Object Facility metamodel (MOF). Like other MOF-based specifications, UML has allowed software developers to concentrate more on design and architecture[citation needed].
UML models may be automatically transformed to other representations (e.g. Java) by means of QVT-like transformation languages, supported by the OMG.
UML is extensible, offering the following mechanisms for customization: profiles and stereotype. The semantics of extension by profiles have been improved with the UML 2.0 major revision.
PRG TO CHECK WEATHER A STRING IS PALINDROME OR NOT
#include
#include
#include
#include
void main()
{clrscr();
char str[30],flag=0;
int n;
float i;
cout<<"enter the string which is to be checked palindrome";
gets(str);
n=(strlen(str)-1);
for(i=0;i<=n/2;i++)
if(str[i]!=str[n-i])
{ flag=1;}
if(flag==0)
cout<<"palindrome";elsecout<<"not a palindrome" ;
getch();
}
#include
#include
#include
void main()
{clrscr();
char str[30],flag=0;
int n;
float i;
cout<<"enter the string which is to be checked palindrome";
gets(str);
n=(strlen(str)-1);
for(i=0;i<=n/2;i++)
if(str[i]!=str[n-i])
{ flag=1;}
if(flag==0)
cout<<"palindrome";elsecout<<"not a palindrome" ;
getch();
}
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