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Homework?<br />
<br />
<a href="http://en.wikipedia.org/wiki/System_call" rel="ugc">http://en.wikipedia.org/wiki/System_call</a>
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Homework?

http://en.wikipedia.org/wiki/System_call [http://en.wikipedia.org/wiki/System_call]

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It's not homework at all.. I just started a class in operating system and I just don't get it.. is it like a call to a program?
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It's not homework at all.. I just started a class in operating system and I just don't get it.. is it like a call to a program?

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is it the same basically to ask the operating system to have certain access/features that the kernel mode supplies?
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is it the same basically to ask the operating system to have certain access/features that the kernel mode supplies?

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Yes.<br />
<br />
<a href="http://www.linfo.org/kernel_mode.html" rel="ugc">http://www.linfo.org/kernel_mode.html</a>
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Yes.

http://www.linfo.org/kernel_mode.html [http://www.linfo.org/kernel_mode.html]

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Can you give me an example of an system call in windows?
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Can you give me an example of an system call in windows?

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From:<br />
<br />
<a href="http://msdn.microsoft.com/en-us/library/bb540534(VS.85).aspx" rel="ugc">http://msdn.microsoft.com/en-us/library/bb540534(VS.85).aspx</a><br />
<br />
Which has sample code using CreateFile, ReadFile, and WriteFile<br />

<pre><code id="code-248927">HANDLE hFile;  
hFile = CreateFile(argv[1],               // file to open
                   GENERIC_READ,          // open for reading
                   FILE_SHARE_READ,       // share for reading
                   NULL,                  // default security
                   OPEN_EXISTING,         // existing file only
                   FILE_ATTRIBUTE_NORMAL, // normal file
                   NULL);                 // no attr. template</code></pre>
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From:

http://msdn.microsoft.com/en-us/library/bb540534(VS.85).aspx [http://msdn.microsoft.com/en-us/library/bb540534(VS.85).aspx]

Which has sample code using CreateFile, ReadFile, and WriteFile


HANDLE hFile;  
hFile = CreateFile(argv[1],               // file to open
                   GENERIC_READ,          // open for reading
                   FILE_SHARE_READ,       // share for reading
                   NULL,                  // default security
                   OPEN_EXISTING,         // existing file only
                   FILE_ATTRIBUTE_NORMAL, // normal file
                   NULL);                 // no attr. template

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<div class="content wysiwyg-content">
what is the purpose of a system call in an OS?
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what is the purpose of a system call in an OS?

system calls in operating system

Software is any set of instructions that directs a computer to perform specific tasks or operations. Computer software consists of programs, libraries and related non-executable data (such as documentation). Computer software is non-tangible, contrasted with computer hardware, which is the physical component of computers. Software written in a machine language is known as "machine code". However, in practice, software is usually written in high-level programming languages than machine language. High-level languages are translated into machine language using a compiler or interpreter or a combination of the two.

Software

Operating systems perform basic tasks, such as recognizing input from the keyboard, sending output to the display screen, keeping track of files and directories on the disk, and controlling peripheral devices such as disk drives and printers. For large systems, the operating system makes sure that different programs and users running at the same time do not interfere with each other. The operating system is also responsible for security, ensuring that unauthorized users do not access the system. Operating systems provide a software platform on top of which other programs, called application programs, can run.