Microsoft KB Archive/163920

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HOWTO: Getting Floppy Drive Type Information

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Q163920

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The information in this article applies to:


 * Microsoft Win32 Application Programming Interface (API), used with:
 * the operating system: Microsoft Windows NT, versions 3.51, 4.0
 * Microsoft Windows 95
 * the operating system: Microsoft Windows 2000

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SUMMARY
Some Win32 applications need to determine whether a disk drive is a floppy drive and the size of the drive. This article provides a sample program that illustrates how to determine the type of drive corresponding to a drive letter. For example, it will determine if the drive is a 3.5" floppy drive, or a 5.25" floppy drive.

MORE INFORMATION
The technique that Win32 applications use to determine the type of floppy drive differs between Windows 95 and Windows NT. On Windows 95, applications use DeviceIoControl to call VWIN32. On Windows NT, applications use DeviceIoControl to issue the IOCTL_DISK_GET_MEDIA_TYPES function. The following sample program determines which Windows operating system is running and then uses the proper technique.

Sample Code
  #include    #include    #include                    // Windows NT IOCTL codes #include                     // Windows 95 IOCTL codes

/*     The  header file is part of the Windows 95 DDK. If you don't have the Windows 95 DDK, then use the definitions below. */

#ifndef VWIN32_DIOC_DOS_IOCTL #define VWIN32_DIOC_DOS_IOCTL 1

typedef struct _DIOC_REGISTERS { DWORD reg_EBX; DWORD reg_EDX; DWORD reg_ECX; DWORD reg_EAX; DWORD reg_EDI; DWORD reg_ESI; DWORD reg_Flags; }DIOC_REGISTERS, *PDIOC_REGISTERS;

#endif

// Intel x86 processor status fla #define CARRY_FLAG 0x1

#pragma pack(1) typedef struct _DOSDPB { BYTE   specialFunc;    // BYTE   devType;        // WORD   devAttr;        // WORD   cCyl;           // number of cylinders BYTE   mediaType;      // WORD   cbSec;          // Bytes per sector BYTE   secPerClus;     // Sectors per cluster WORD   cSecRes;        // Reserved sectors BYTE   cFAT;           // FATs WORD   cDir;           // Root Directory Entries WORD   cSec;           // Total number of sectors in image BYTE   bMedia;         // Media descriptor WORD   secPerFAT;      // Sectors per FAT WORD   secPerTrack;    // Sectors per track WORD   cHead;          // Heads DWORD  cSecHidden;     // Hidden sectors DWORD  cTotalSectors;  // Total sectors, if cbSec is zero BYTE   reserved[6];    // } DOSDPB, *PDOSDPB; #pragma pack

/*     GetDriveFormFactor returns the drive form factor.

It returns 350 if the drive is a 3.5" floppy drive.     It returns 525 if the drive is a 5.25" floppy drive. It returns 800 if the drive is a 8" floppy drive.     It returns   0 on error.      It returns   1 if the drive is a hard drive.      It returns   2 if the drive is something else.

iDrive is 1 for drive A:, 2 for drive B:, etc.

Note that iDrive is not range-checked or otherwise validated. It is the responsibility of the caller only to pass values for iDrive between 1 and 26 (inclusive).

Although the function, as written, returns only the drive form factor, it can easily be extended to return other types of     drive information. */

DWORD GetDriveFormFactor(int iDrive) {      HANDLE h;       TCHAR tsz[8]; DWORD dwRc;

if ((int)GetVersion < 0) {  // Windows 95

/*            On Windows 95, use the technique described in             the Knowledge Base article Q125712 and in MSDN under "Windows 95 Guide to Programming", "Using Windows 95            features", "Using VWIN32 to Carry Out MS-DOS Functions". */          h = CreateFileA("\\\\.\\VWIN32", 0, 0, 0, 0,                           FILE_FLAG_DELETE_ON_CLOSE, 0);

if (h != INVALID_HANDLE_VALUE) {            DWORD          cb; DIOC_REGISTERS reg; DOSDPB        dpb;

dpb.specialFunc = 0; // return default type; do not hit disk

reg.reg_EBX  = iDrive;       // BL = drive number (1-based) reg.reg_EDX  = (DWORD)&dpb;  // DS:EDX -> DPB reg.reg_ECX  = 0x0860;       // CX = Get DPB reg.reg_EAX  = 0x440D;       // AX = Ioctl reg.reg_Flags = CARRY_FLAG;  // assume failure

// Make sure both DeviceIoControl and Int 21h succeeded. if (DeviceIoControl (h, VWIN32_DIOC_DOS_IOCTL, &reg, sizeof(reg), &reg, sizeof(reg), &cb, 0)                && !(reg.reg_Flags & CARRY_FLAG)) {               switch (dpb.devType) {               case 0: // 5.25 360K floppy case 1: // 5.25 1.2MB floppy dwRc = 525; break;

case 2: // 3.5 720K floppy case 7: // 3.5 1.44MB floppy case 9: // 3.5 2.88MB floppy dwRc = 350; break;

case 3: // 8" low-density floppy               case 4: // 8" high-density floppy dwRc = 800; break;

case 5: // hard drive dwRc = 1; break;

case 6: // tape drive case 8: // optical disk dwRc = 2; break;

default: // unknown dwRc = 0; break; }            }             else dwRc = 0;

CloseHandle(h); }         else dwRc = 0;

}     else { // Windows NT

/*           On Windows NT, use the technique described in the Knowledge Base article Q115828 and in the "FLOPPY" SDK sample. */         wsprintf(tsz, TEXT("\\\\.\\%c:"), TEXT('@') + iDrive); h = CreateFile(tsz, 0, FILE_SHARE_WRITE, 0, OPEN_EXISTING, 0, 0); if (h != INVALID_HANDLE_VALUE) {           DISK_GEOMETRY Geom[20]; DWORD cb;

if (DeviceIoControl (h, IOCTL_DISK_GET_MEDIA_TYPES, 0, 0, Geom, sizeof(Geom), &cb, 0)               && cb > 0) {              switch (Geom[0].MediaType) {              case F5_1Pt2_512: // 5.25 1.2MB floppy case F5_360_512: // 5.25 360K  floppy case F5_320_512: // 5.25 320K  floppy case F5_320_1024: // 5.25 320K floppy case F5_180_512: // 5.25 180K  floppy case F5_160_512: // 5.25 160K  floppy dwRc = 525; break;

case F3_1Pt44_512: // 3.5 1.44MB floppy case F3_2Pt88_512: // 3.5 2.88MB floppy case F3_20Pt8_512: // 3.5 20.8MB floppy case F3_720_512:  // 3.5 720K   floppy dwRc = 350; break;

case RemovableMedia: dwRc = 2; break;

case FixedMedia: dwRc = 1; break;

default: dwRc = 0; break; }           }            else dwRc = 0;

CloseHandle(h); }        else dwRc = 0; }

/*        If you are unable to determine the drive type via ioctls, then it means one of the following:

1. It is hard drive and we do not have administrator privilege 2. It is a network drive 3. The drive letter is invalid

GetDriveType can distinguish these three cases. */      if (dwRc == 0) {        wsprintf(tsz, TEXT("%c:\\"), TEXT('@') + iDrive);

switch (GetDriveType(tsz)) {           case DRIVE_FIXED: dwRc = 1; break; case DRIVE_REMOVABLE: case DRIVE_REMOTE: case DRIVE_CDROM: case DRIVE_RAMDISK: dwRc = 2; break; default: dwRc = 0; }     }      return dwRc; }

/*     Sample program:  Count from A to Z and display the drive form factor for each drive that exists. */   int main(int argc, char **argv) {     int iDrive;

for (iDrive = 1; iDrive <= 26; ++iDrive) {        DWORD dwFF = GetDriveFormFactor(iDrive);

if (dwFF) printf("%c: = %d\n", TEXT('@') + iDrive, dwFF); }     return 0; }