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Physical/Logical partition info - how to get?

I have a computer with one hard disk. the disk is splited into two logical drives (C:, D:). I need to write a procedure that retrive this data (one hard disk with two logical drives).
The real task is to know how many hard disks the computer have( IDE or SCSI ) and which logical drive reside in which hard disk.
I know how to do this by reading from the registry in win95, but the NT registry is different from the win95 one, so I can't use this.
I also tried use the DeviceIOCtrl, but failed to make it work right.
There is also an int 21 service that deals with the subject but I couldn't make it work properly.
I already post this question in the delphi section but they helped none. Please answer this only if you REALLY know the answer.
1 Solution
Use the DevIoControl IOCTL_DISK_GET_DRIVE_LAYOUT operation.  This gets you a DRIVE_LAYOUT_INFORMATION structure which points to a series of PARTITION_INFORMATION structutes for each partition.
TheSwineAuthor Commented:
As I wrote before, I failed make this work using DeviceIOControl. I am familiar with everything you wrote, please add some full sample code, Thanks.
TheSwineAuthor Commented:
Adjusted points to 305
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You might recognize me, cause I already tried to answer your question
in the delphi section.
You see, I am also interessed in solving that problem.
I'm writing here now to keep the question alive ;)
Would you agree to help me solve your problem ?
May you send me the code you already tryed out ?
I will only have time to answer that question next week,
cause for now I still have exams at school :(
Unfortunately I had done a part of the answer yesterday,
but since I'm very new to using NT, I made some changes that
crashed the NT partition, so I lost the code source I wrote in temp ;).
I wrote C++ in parallel with pascal, and I did not get the same
result in pascal. this might be because I had to write the
structures by myself. How do you translate following in pascal ?

partLayout test[1];

partLayout is the type. The msdn says this is a variable array.
How do you make such a thing in pascal?

I'm waiting your suggestions ?

Dear Jeurk,

The partLayout test[1]; code is a generic code that indicates the test variable may contain several partLayout structures attached end to end in the memory: The direct translation is

  test : array[0..0] of partLayout;

but I should see the actual API help fragment to correcly interpret. If need help please give the keyword for WIN32 help

Hi Igor,
Your help is welcome, i'm at school for now.
I'll come back tomorrow and post the structures I need
to be translated.

CU, Jeurk
Tommy HuiEngineerCommented:
Here's some sample code:

void CDrvLayView::AddLine(const CString& msg)
      CRichEditCtrl& ctrl = GetRichEditCtrl();

      long l = ctrl.GetTextLength();
      ctrl.SetSel(l, l);

struct _PTMAP
      int   m_PT;
      char* m_Info;
} g_PTMap[] =
      { PARTITION_ENTRY_UNUSED, "Entry unused" },
      { PARTITION_FAT_12, "Specifies a partition with 12-bit FAT entries" },
      { PARTITION_XENIX_1, "Specifies a Xenix type 1 partition" },
      { PARTITION_XENIX_2, "Specifies a Xenix type 2 partition" },
      { PARTITION_FAT_16, "Specifies a partition with 16-bit FAT entries" },
      { PARTITION_EXTENDED, "Specifies an extended partition entry" },
      { PARTITION_HUGE, "Specifies an MS-DOS V4 huge partition" },
      { PARTITION_IFS, "Specifies an IFS partition" },
      { PARTITION_PREP, "Specifies a PowerPC Reference Platform partition" },
      { PARTITION_UNIX, "Specifies a UNIX partition" },
      { VALID_NTFT, "Specifies an NTFT partition" },
      { PARTITION_XINT13, "Specifies a Windows 95 partition that uses extended int13 services" },
      { PARTITION_XINT13_EXTENDED, "Same as PARTITION_EXTENDED, but uses extended int13 services" },

CString ConvertBool(BOOL b)
      return b ? "True" : "False";

void CDrvLayView::OnDrivesSelChange()
      CString driveLetter =  g_DriveTB->GetCurrentDrive();

      CString msg;
      msg.Format("Changing to %s.\r\n", driveLetter);

      CString drive = "\\\\.\\" + driveLetter;

            OPEN_EXISTING, 0, NULL);

      if (h == INVALID_HANDLE_VALUE)
            msg.Format("Failed to open %s. GetLastError() returned %d\r\n",
                  driveLetter, GetLastError());
            DWORD bytesReturned = 0;

            if (!DeviceIoControl(h, IOCTL_DISK_GET_PARTITION_INFO, NULL, 0,
                  &pi, sizeof(pi), &bytesReturned, NULL))
                  msg.Format("Failed to obtain partition info for %s. GetLastError() returned %d\r\n",
                        driveLetter, GetLastError());
                  msg.Format("Offset at 0x%08X:0x%08X\r\n", pi.StartingOffset.HighPart,

                  msg.Format("Length at 0x%08X:0x%08X\r\n", pi.PartitionLength.HighPart,

                  msg.Format("Number of hidden sectors: %d\r\n", pi.HiddenSectors);

                  msg.Format("Number of partitions: %d\r\n", pi.PartitionNumber);

                  CString partitionType = "Unknown";

                  for (int i = 0; i < sizeof(g_PTMap) / sizeof(g_PTMap[0]); i++)
                        if (pi.PartitionType == g_PTMap[i].m_PT)
                              partitionType = g_PTMap[i].m_Info;

                  msg.Format("Type of partitions: %s\r\n", partitionType);

                  msg.Format("Bootable? %s\r\n", ConvertBool(pi.BootIndicator));

                  msg.Format("Recognized? %s\r\n", ConvertBool(pi.RecognizedPartition));

//                  msg.Format("Rewritable? %s\r\n", ConvertBool(pi.RewritePartition));
//                  AddLine(msg);


TheSwineAuthor Commented:
Thanks tui.
It will take me about a week to check it up cause I'm very busy right now. I'll get back to you in few day's
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