Update of /cvsroot/opengtoolkit/portIO/c_source
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv10877/c_source
Modified Files:
Description.htm
Log Message:
Some small formatting changes
Index: Description.htm
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RCS file: /cvsroot/opengtoolkit/portIO/c_source/Description.htm,v
retrieving revision 1.2
retrieving revision 1.3
diff -C2 -d -r1.2 -r1.3
*** Description.htm 11 Mar 2004 09:46:45 -0000 1.2
--- Description.htm 11 Mar 2004 09:54:04 -0000 1.3
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</head>
<body>
! <br>
! <big style="font-weight: bold;"><big><img
! style="width: 36px; height: 36px;" alt=""
! src="file:///D:/CVS/OpenG/development/portIO/ogportio.bmp"> OpenG Port IO Driver<br>
! </big><br>
! Introduction<br>
</big><br>
For Windows NT based systems (NT 4, 2000, XP, 2003) access to hardware
resources from user space (e.g.. any application) is restricted to
--- 7,16 ----
</head>
<body>
! <big style="font-weight: bold;"><big><img style="width: 36px; height: 36px;" alt=""
! src="file:///D:/CVS/OpenG/development/portIO/ogportio.bmp"> OpenG Port IO Driver</big>
</big><br>
+ <br>
+ <big style="font-weight: bold;">Introduction</big><br>
+ <br>
For Windows NT based systems (NT 4, 2000, XP, 2003) access to hardware
resources from user space (e.g.. any application) is restricted to
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*** 20,24 ****
catched by the Windows NT kernel. The kernel then displays a dialog (or
optionally offers to start a system debugger) and terminates the
! process which caused the Protection Fault.<br>
<br>
If you want to program prototype hardware, this restriction is rather
--- 19,23 ----
catched by the Windows NT kernel. The kernel then displays a dialog (or
optionally offers to start a system debugger) and terminates the
! process that caused the Protection Fault.<br>
<br>
If you want to program prototype hardware, this restriction is rather
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*** 38,45 ****
in comparison to the actual time needed for the device driver call
itself. For our port driver however this is different. A port address
! read itself typically takes less than 1 us while the time needed to
switch from user space to kernel space and back is typically somewhere
! around 100us on an older 866MHz Pentium system. You can see that while
! the IO port access itself is quite fast the necessary context switches
are expensive. Therefore it would be interesting if we had a
possibility to enable port address access directly from the user
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in comparison to the actual time needed for the device driver call
itself. For our port driver however this is different. A port address
! read itself typically takes less than 1 µs while the time needed to
switch from user space to kernel space and back is typically somewhere
! around 100 µs on an older 866MHz Pentium system. You can see that while
! the IO port access itself is quite fast, the necessary context switches
are expensive. Therefore it would be interesting if we had a
possibility to enable port address access directly from the user
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*** 57,61 ****
development :-) or even damage the hardware or destroy information in
the system or on it's connected devices.<br>
! <big style="font-weight: bold;"><br>
Manipulating the IOPM (IO Permission bitMap)</big><br>
<br>
--- 56,61 ----
development :-) or even damage the hardware or destroy information in
the system or on it's connected devices.<br>
! <br>
! <big style="font-weight: bold;">
Manipulating the IOPM (IO Permission bitMap)</big><br>
<br>
|
