ID: Q163920
3.51 4.00 WINDOWS NT
kbhowto
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.
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.
#include <windows.h>
#include <stdio.h>
#include <winioctl.h> // Windows NT IOCTL codes
#include <vwin32.h> // Windows 95 IOCTL codes
/*
The <vwin32.h> 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, ®,
sizeof(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;
}
This article supplements the following articles in the Microsoft Knowledge Base:
ARTICLE-ID:Q115828
TITLE :HOWTO: Getting Floppy Drive Information
ARTICLE-ID:Q125712
TITLE :HOWTO: Opening Volumes Under Windows 95
Keywords : kbcode kbAPI kbKernBase kbGrpKernBase
Version : 3.51 4.00
Platform : NT WINDOWSLast Reviewed: May 23, 1998