Microsoft KB Archive/262347

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HOWTO: Use Int 13h in Windows 95 and Windows 98

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Q262347

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The information in this article applies to:


 * Microsoft Windows 98 Driver Development Kit (DDK)
 * Microsoft Windows 95 Driver Development Kit (DDK)

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SUMMARY
Applications interface with VWIN32 by using the DeviceIoControl function to read/write absolute and physical sectors on floppy and hard disk drives. But reading/writing physical sectors on a hard disk drive will fail because hard disk physical sectors are protected by Windows 95 and Windows 98.

MORE INFORMATION
It is possible to read/write physical sectors on a hard disk from a VxD, by simulating Int 13h. Such a VxD would implement a W32_DEVICE_CONTROL interface for applications to talk to the VxD. The W32_DEVICE_CONTROL handler should do the following:


 * 1) Allocate V86 memory by using V86MMGR_Allocate_Buffer.
 * 2) Push_Client_State.
 * 3) Begin_Nest_V86_Exec.
 * 4) Pass Int 13h parameters (or Ext Int 13h parameters) in Client_?? registers.
 * 5) Exec_Int.
 * 6) End_Nest_Exec.
 * 7) Pop_Client_State.
 * 8) Copy the contents from V86 memory to a buffer.
 * 9) Deallocate V86 memory immediately (step 8 can be done during deallocation).

Additional query words: Int 13h, Physical Sectors

Keywords : kbDDK kbDSupport kbGrpDSWin9xDDK

Issue type : kbhowto

Technology : kbAudDeveloper kbWin95search kbWin98search kbWin95DDKSearch kbWinDDKSearch kbWin98DDKSearch kbWin95DDK kbWin98DDK