Contributor: P. BELOW
{+------------------------------------------------------------
 | Unit Drives
 |
 | Version: 2.0 Last modified: 02/27/95, 21:49:56
 | Author : P. Below CIS [100113,1101]
 | Project: Common utilities
 | Units required (only for the Implementation section):
 | DOS: Dos (Borland)
 |	 Windows: Win31 (Borland), WinDOS (Borland), Wintypes (Borland),
 | WinProcs (Borland), DMPI (own);
 | Description:
 | This Unit collects routines to gather information about
 |	 the disk drives on a system in both DOS and Windows. You can
 |	 build a drive map with a single procedure call. In addition
 |	 to drive type checking the volume name, serial number, and
 |	 FAT type for local fixed disks or the netshare name for 
 |	 networked drives are also retrieved.
 |	 Low-level routines for all the subfunctions involved in 
 |	 building the drive map are exported, too. You can thus get
 |	 the media info or disk paramter block for floppy disk or other
 |	 removable media drives "by hand", if necessary. 
 |	 Most of the low level stuff uses DOS IOCTL functions, even
 |	 for the Windows version ( GetDriveType is just to limited ).
 |	 CD-ROM identification uses the MSCDEX int 2Fh interface.
 |
 |	 This Unit has been checked under real mode DOS and Windows
 |	 (Win 3.1, WfWg 3.11, Win NT 3.5 ) but _not_ under protected
 |		mode DOS (DPMI)!
 | Copyright (C) 1994,1995 by Peter Below 
 | This code is released to the public domain, use it as you see fit
 |	 in your own programs (at your own risk, of course) but you should
 |	 include a note of the origin of this code in your program.
 +------------------------------------------------------------}
Unit Drives;
Interface
Const
 DRIVE_CDROM = 5;
 DRIVE_RAM = 6;
 Min_DriveNums = 1; (* drive a: *)
 Max_DriveNums = 26; (* drive z: *) 
Type
 TDriveTypes = ( FLOPPY, HARDDISK, REMAPPED, REMOTE, CD_ROM,
 RAMDISK, INVALID );
 TDTypeSet = SET OF TDriveTypes;
 TDriveNums = Min_DriveNums..Max_DriveNums;
 (* range A: To Z: of drive letters *)
 TDriveSet = SET OF TDriveNums; 
 TDeviceName = ARRAY [0..127] OF CHAR;
 TDiskInfo = Record (* this is a DOS structure used by GetMediaID
 but modified to allow for asciiz strings *)
 InfoLevel: WORD;
 serialNo: LongInt;
 volName : ARRAY [0..11] OF CHAR;
 FATType : ARRAY [0..8] OF CHAR;
 End;
 TDriveInfo = Record
 Flags: TDTypeSet;
 Case Boolean OF
 TRUE: (* For network drives *)
 (DevName: TDeviceName);
 FALSE: (* For all other drives *)
 (Info: TDiskInfo);
 End;
 TDriveMap = ARRAY [TDriveNums] OF TDriveInfo;
 PDriveMap = ^TDriveMap;
 LP_DPB = ^DPB; 
 DPB = Record (* Disk Parameter Block as per MSDOS Programmer's Reference *)
 dpbDrive : BYTE;
 dpbUnit : BYTE;
 dpbSectorSize : WORD;
 dpbClusterMask : BYTE;
 dpbClusterShift: BYTE;
 dpbFirstFAT : WORD;
 dpbFATCount : BYTE;
 dpbRootEntries : WORD;
 dpbFirstSector : WORD;
 dpbMaxCluster : WORD;
 dpbFATSize : WORD;
 dpbDirSector : WORD;
 dpbDriverAddr : Pointer;
 dpbMedia : BYTE;
 dpbFirstAccess : BYTE;
 dpbNextDPB : LP_DPB;
 dpbNextFree : WORD;
 dpbFreeCnt : WORD;
 End;
Procedure MyGetDriveType( n: TDriveNums; Var f: TDTypeSet );
Procedure GetDriveInfo( n: TDriveNums; Var di: TDriveInfo );
Procedure BuildDriveMap( Var DMap: TDriveMap );
Function MSCDexIsloaded: Boolean;
Function DriveIsCDROM( n: TDriveNums ): Boolean;
Function DriveIsRamdisk( n: TDriveNums ): Boolean;
Function GetDiskParameterBlock( drive: TDriveNums ): LP_DPB;
Function GetLastdrive: TDriveNums;
{ the following functions map directly to DOS IOCTL calls }
Function MediumIsRemovable( n: TDriveNums ): TDriveTypes;
Function DriveIsRemote( n: TDriveNums ): Boolean;
Function DriveIsRemapped( n: TDriveNums ): Boolean;
Function GetMediaID ( Drive: Word; Var info: TDiskInfo ): Boolean;
Function GetDriveMapping( n: TDriveNums ): TDriveNums;
Procedure MapLogicalDrive( n: TDriveNums );
Implementation
Uses Strings,
{$IFDEF WINDOWS}
 Win31, WinDOS, Wintypes, WinProcs, DMPI;
{$ELSE}
 DOS;
{$ENDIF}
{************************************************************
 * Function MediumIsRemovable
 *
 * Parameters:
 *	n: the drive number to check, 1= A:, 2=B: etc.
 * Returns:
 *	one of the three drive types INVALID, FLOPPY or HARDDISK
 * Description:
 *	This function uses DOS IOCTL function 4408ドル to check a drive
 *	for removable media. It can also be used to check for a drives
 *	existance.
 *	Should work for DOS, Windows, and DPMI.
 *
 *Created: 02/26/95 20:49:03 by P. Below
 ************************************************************}
Function MediumIsRemovable( n: TDriveNums ): TDriveTypes;
 Var
 	res: Word;
 Begin
 	asm
		 mov ax, 4408ドル 	(* IOCTL is drive changeable function *)
			mov bl, n
{$IFDEF WINDOWS}
 call Dos3Call
{$ELSE}
 int 21ドル
{$ENDIF}
			mov res, ax
			{ Our handling of the result makes the following asumptions here:
			 If the function succeeds (carry flag clear), the return in ax
				will be 0 for removable and 1 for fixed medium.
				If the function fails (carry flag set), the error code in ax
				will be 1, if the device driver does not know how to handle the
				function (in which case we assume a fixed disk, also ax=1, safe bet 
				according to MS docs) or it will be $F, if the drive is invalid. 
			 }
		End; { asm }
		Case res Of
			0: MediumIsRemovable := FLOPPY;
			1: MediumIsRemovable := HARDDISK
		Else
		 MediumIsRemovable := INVALID;
		End; { Case }
 End; (* BasicDriveType *)
{************************************************************
 * Function DriveIsRemote
 *
 * Parameters:
 *	n: the drive number to check, 1= A:, 2=B: etc.
 * Returns:
 *	TRUE, if the drive is remote, FALSE if it is local or invalid.
 * Description:
 *	This function uses DOS IOCTL function 4409ドル to check whether 
 *	a drive is remote or local.
 *	Should work for DOS, Windows, and DPMI.
 *
 *Created: 02/26/95 21:12:32 by P. Below
 ************************************************************}
Function DriveIsRemote( n: TDriveNums ): Boolean; Assembler;
 	Asm
	 mov ax, 4409ドル 	(* IOCTL is drive remote function *)
		mov bl, n
{$IFDEF WINDOWS}
 call Dos3Call
{$ELSE}
 int 21ドル
{$ENDIF}
		mov ax, False (* assume error, in which case we return false *) 
		jc @error
		and dx, 1000ドル (* remote drives have bit 12 set *)
		jz @error
		inc ax
	@error:
 End; (* DriveIsRemote *)
{************************************************************
 * Function DriveIsRemapped
 *
 * Parameters:
 *	n: the drive number to check, 1= A:, 2=B: etc.
 * Returns:
 *	TRUE, if the drive can be remapped, FALSE if not or if it is invalid.
 * Description:
 *	This function uses DOS IOCTL function 440ドルE to check whether 
 *	a drive can be remapped.
 *	Should work for DOS, Windows, and DPMI.
 *
 *Created: 02/26/95 21:21:46 by P. Below
 ************************************************************}
Function DriveIsRemapped( n: TDriveNums ): Boolean; Assembler;
 Asm
	 mov ax, 440ドルE 	(* IOCTL get logical drive mapping function *)
		mov bl, n
{$IFDEF WINDOWS}
 call Dos3Call
{$ELSE}
 int 21ドル
{$ENDIF}
		jc @error
		cmp al, 0 (* if carry not set, ax returns last drive number *)
		je @error (* of the mapped drive, or 0, if the block device has *)
		mov ax, True (* only one drive assigned to it. *)
		jmp @done
	@error:
	 mov ax, false
	@done:
 End; (* DriveIsRemapped *)
{************************************************************
 * Function GetDriveMapping
 *
 * Parameters:
 *	n: the drive number to check, 1= A:, 2=B: etc.
 * Returns:
 *	The logical drive number the drive is mapped to, or the number
 *	passed in n, if the drive is not mapped or is invalid.
 * Description:
 *	This function uses DOS IOCTL function 440ドルE to check whether 
 *	a drive is remapped.
 *	Should work for DOS, Windows, and DPMI.
 * Error Conditions:
 *	none
 *Created: 02/26/95 21:21:46 by P. Below
 ************************************************************}
Function GetDriveMapping( n: TDriveNums ): TDriveNums; Assembler;
 Asm
	 mov ax, 440ドルE 	(* IOCTL get logical drive mapping function *)
		mov bl, n
{$IFDEF WINDOWS}
 call Dos3Call
{$ELSE}
 int 21ドル
{$ENDIF}
		jc @error				(* if no error *)
		or al, al (* check return, 0 means not remapped *)
		jnz @done (* if remapped, return mapped drive number *)
	@error:
	 mov al, n (* else return original drive number *)
 xor ah, ah
	@done:
 End; (* GetDriveMapping *)
{************************************************************
 * Procedure MapLogicalDrive
 *
 * Parameters:
 *	n: the physical drive number to map, 1= A:, 2=B: etc.
 * Description:
 *	Uses DOS IOCTL function 440ドルF to map the physical drive
 *	passed to the next logical drive number the block device
 *	driver supports. Does nothing for drives that are not
 *	mappable or invalid.
 *	Use it with n=1 to map the floppy drive on a single floppy
 *	system between A: and B:, use GetDriveMapping to check the
 *	current mapping.
 *	Should work for DOS, Windows, and DPMI.
 *
 *Created: 02/26/95 21:51:34 by P. Below
 ************************************************************}
Procedure MapLogicalDrive( n: TDriveNums ); assembler;
 Asm
 mov AX, 440ドルF
 mov BL, n
{$IFDEF WINDOWS}
 call Dos3Call
{$ELSE}
 int 21ドル
{$ENDIF}
 End ;
Type
 TMediaID = Record (* This is the MS-DOS original MediaID structure *)
 wInfoLevel: WORD;
 dwSerialNumber: LongInt;
 VolLabel: ARRAY [0..10] of Char;
 FileSysType: ARRAY [0..7] of Char;
 End;
 PMediaID = ^TMediaID;
{************************************************************
 * Function GetMediaID 
 *
 * Parameters:
 *	Drive: 0 = default drive, 1 =A: etc.
 *	Info : Record to receive the media id info, filled with 0
 *	 if function fails.
 * Returns:
 *	True if successful, False if error. 
 * Description:
 *	This function uses DOS IOCTL function 440ドルD, subfunction 0866ドル
 *	to read the media ID record from the disks bootsector. For 
 *	Windows, this requires use of DPMI.
 *	Works for DOS and Windows, not tested for DPMI!
 *
 *Created: 02/26/95 21:44:02 by P. Below
 ************************************************************}
{$IFDEF WINDOWS}
 (*************************************************************************
 / GetMediaID() - Windows version
 /
 / Get Media ID by simulating an Int 21h, AX=440Dh, CX=0866h in real mode.
 / Setup RealModeReg To contain a real mode pointer To a MediaID structure
 /************************************************************************)
Function GetMediaID ( Drive: Word; Var info: TDiskInfo ): Boolean;
 Var
 RealModeReg: TRealModeReg;
 dwGlobalDosBuffer: LongInt;
 lpRMMediaID: PMediaID;
 Begin
 GetMediaID := FALSE;
 FillChar( info, Sizeof( info ), 0 );
 { Get a real mode addressable buffer For the MediaID structure }
 dwGlobalDosBuffer := GlobalDosAlloc(sizeof(TMediaID));
 If (dwGlobalDosBuffer  0) Then Begin
 { Now initialize the real mode register structure }
 FillChar(RealModeReg, sizeof(RealModeReg), 0);
 RealModeReg.rmEAX := 440ドルD; { IOCTL For Block Device }
 RealModeReg.rmEBX := LongInt(Drive); { 0 = default, 1 = A, 2 = B, etc. }
 RealModeReg.rmECX := 0866ドル; { Get Media ID }
 RealModeReg.rmDS := HIWORD(dwGlobalDosBuffer); { *real mode segment* }
 { Now simulate the real mode interrupt }
 If RealInt(21,ドル RealModeReg) and { int simulation ok?}
 ((RealModeReg.rmCPUFlags and 0001ドル)=0) { carry clear? }
 Then Begin
 lpRMMediaID := PMEDIAID( MakeLong(0, LOWORD(dwGlobalDosBuffer)));
 info.InfoLevel := lpRMMediaID^.wInfoLevel;
 info.serialNo := lpRMMediaID^.dwSerialNumber;
 StrMove( info.volName, lpRMMediaID^.VolLabel, 11 );
 StrMove( info.FATType, lpRMMediaID^.FileSysType, 8 );
 GetMediaID := TRUE;
 End;
 GlobalDosFree(LOWORD(dwGlobalDosBuffer));
 End;
 End;
{$ELSE}
 (*************************************************************************
 | GetMediaID() - DOS version
 |
 |Get Media ID using Int 21h, AX=440Dh, CX=0866h in real mode.
 |WARNING! Assumes DOS-Version> 4.0!
 ************************************************************************)
Function GetMediaID ( Drive: Word; Var info: TDiskInfo ): Boolean;
 Label error;
 Var
 MediaID: TMediaID;
 Begin
 GetMediaID := FALSE;
 FillChar( info, Sizeof( info ), 0 );
		asm
		 push ds
		 mov ax, 440ドルD; { IOCTL For Block Device }
			mov bx, Drive; { 0 = default, 1 = A, 2 = B, etc. }
 mov cx, 0866ドル; { Get Media ID }
			mov dx, ss { point ds:dx at MediaID }
			mov ds, dx
			lea dx, MediaID
			int 21ドル
			pop ds
			jc error
		End;
 info.InfoLevel := MediaID.wInfoLevel;
 info.serialNo := MediaID.dwSerialNumber;
 StrMove( @info.volName, @MediaID.VolLabel, 11 );
 StrMove( @info.FATType, @MediaID.FileSysType, 8 );
 GetMediaID := TRUE;
	error:
 End;
{$ENDIF}
{************************************************************
 * Function MSCDExIsLoaded
 *
 * Parameters:
 *	none
 * Returns:
 *	True, if MSCDEX is loaded, False otherwise
 * Description:
 *	Uses the MSCDEX Int 2ドルF interface, function 00ドル.
 *	Should work for DOS, Windows, and DPMI.
 *
 *Created: 02/26/95 21:55:17 by P. Below
 ************************************************************}
Function MSCDExIsLoaded: Boolean; assembler;
 Asm
 mov AX, 1500ドル (* MSCDEX installed check *)
 xor BX, BX
 int 2ドルF
 xor ax, ax (* set default return value To false *)
 or BX, BX (* returns bx  0 If MSCDEX installed *)
 jz @no_mscdex
 mov al, TRUE
 @no_mscdex:
 End;
{************************************************************
 * Function DriveIsCDROM
 *
 * Parameters:
 *	n: the drive number to check, 1= A:, 2=B: etc.
 * Returns:
 *	True, if the drive is a CD-ROM, False otherwise.
 * Description:
 *	Uses the MSCDEX Int 2ドルF interface, function 0ドルB.
 *	It is not necessary to check for the presence of
 *	MSCDEX first.
 *	Should work for DOS, Windows, and DPMI.
 *
 *Created: 02/26/95 21:57:06 by P. Below
 ************************************************************}
Function DriveIsCDROM( n: TDriveNums ): Boolean; assembler;
 Asm
 mov ax, 150ドルB (* MSCDEX check drive Function *)
 mov cl, n
 xor ch, ch
 dec cx (* 0 = A: etc.*)
		xor bx, bx
 int 2ドルF
		cmp bx, $ADAD (* is MSCDEX present? *) 
		jne @no_cdrom
 or ax, ax
 jz @no_cdrom
 mov ax, True
		jmp @done
 @no_cdrom:
	 mov ax, False
	@done:
 End;
{$IFDEF WINDOWS}
Procedure Beautify( s: PChar );
 (* internal procedure, remove a dot from the volume name,
 padd to 11 chars with blanks *)
 Var
 p: PChar;
 i: Integer;
 Begin
 p := StrScan( s, '.' );
 If p  nil Then
 StrMove( p, p+1, 4 );
 (* padd To 11 chars with blanks *)
 i := StrLen( s );
 While i < 11 Do Begin StrCat( s, ' ' ); INC(i); End; End ; {$ELSE} Procedure Beautify( Var s: string ); (* internal procedure, remove a dot from the volume name, padd to 11 chars with blanks *) Var i: Integer; Begin i := Pos( '.', s ); If i  0 Then
 Delete( s, i, 1 );
 (* padd To 11 chars with blanks *)
 While Length(s) < 11 Do s:= s + ' '; End ; {$ENDIF} {************************************************************ * Procedure GetNetworkShareName [ NOT EXPORTED! ] * * Parameters: * n: the drive number, 1= A:, 2=B: etc., should be a network drive! * name: array of char to take the device name * Description: * This is a internal helper procedure, it does not check its * parameters. name will return an empty string, if the drive is * not a network drive. * *Created: 02/26/95 22:07:49 by P. Below ************************************************************} Procedure GetNetworkShareName( n: TDriveNums; Var name: TDeviceName ); Var Param: ARRAY [0..16] OF CHAR; {$IFNDEF WINDOWS} Buf : ARRAY [0..16] OF CHAR; {$ENDIF} i : Integer; Begin Param[0] := Chr( n - 1 + Ord('A')); Param[1] := ':'; Param[2] := #0; name [0] := #0; {$IFDEF WINDOWS} i := Sizeof( name ); WNetGetConnection( @Param, @name, @i ); {$ELSE} { for plain DOS we need a bit of work, using int 21h, function 5F02h, "Get Assign-List Entry". This entails a search thru the list of all entries. } asm push ds push es push si push di sub bx, bx { bx holds the list index, starts with 0 } mov ax, ss { point ds:si at Buf } mov ds, ax lea si, Buf les di, name { point es:di at name } @next: sub cx, cx mov ax, 5ドルF02 { dos get redirection list entry function } push bx { save current index } push bp { Network Interrupts sez: dx,bp destroyed! } int 21ドル pop bp jc @error { we have an entry, compare its local name in Buf with the drive name in Param, but only if the type returned in bl is 4 (disk drive)} cmp bl, 4 pop bx { restore index } jne @next_bx { try next if no disk drive } mov ax, [ si ] { else get drive letter + colon from Buf } cmp ax, word ptr Param { and compare to Param } je @done { if equal, exit } @next_bx: { else try next index } inc bx jmp @next @error: pop bx { no match found or network not installed, clean } mov byte ptr es:[di], 0 { saved index from stack and return name='' } @done: pop di { restore all saved registers } pop si pop es pop ds End; { Asm } {$ENDIF} End ; {************************************************************ * Procedure GetDiskInfo * * Parameters: * n: the drive number, 1= A:, 2=B: etc. * info: record to take the drive info * Description: * Calls GetMediaID to read the info block from the disk boot * sector, then searches for the volume name. Will return with * a serial number of 0, if GetMediaID is not supported or the * drive is invalid or contains no disk. * *Created: 02/26/95 22:11:35 by P. Below ************************************************************} Procedure GetDiskInfo( n: TDriveNums; Var info: TDiskInfo ); Var fake: Boolean; {$IFDEF WINDOWS} oldsettings: Word; {$ENDIF} Procedure DoItOldStyle; Var {$IFDEF WINDOWS} dinfo: TSearchRec; s: ARRAY [0..fsFilename] of Char; {$ELSE} dinfo: SearchRec; s: PathStr; {$ENDIF} Begin {$IFDEF WINDOWS} StrCopy(s, '@:\*.*' ); s[0] := CHR( Ord( s[0] ) + n ); FindFirst( s, faVolumeID , dinfo ); If DosError = 0 Then Begin Beautify( dinfo.Name ); StrCopy( info.volName, dinfo.Name ); End; If fake Then Begin StrCopy( info.FATType, 'FAT12 '); info.serialNo := 0; End; {$ELSE} s := '@:\*.*'; s[1] := CHR( Ord( s[1] ) + n ); FindFirst( s, VolumeID , dinfo ); If DosError = 0 Then Begin Beautify( dinfo.Name ); StrPCopy( info.volName, dinfo.Name ); End; If fake Then Begin StrPCopy( info.FATType, 'FAT12 '); info.serialNo := 0; End; {$ENDIF} End ; Begin FillChar( info, Sizeof( info ), 0 ); {$IFDEF WINDOWS} oldsettings := SetErrorMode( SEM_FAILCRITICALERRORS ); {$ENDIF} (* check the DOS version *) If Lo( DosVersion )>= 4 Then
 fake := NOT GetMediaID( n, info )
 Else
 fake := TRUE;
 (* we get the volume label thru the old-style method of directory
 search because pre-DOS 5.x may not have it in the boot sector
 and even later versions may either not have it (If the disk was
 formatted by something other than DOS Format) or it may have been
 changed with LABEL, which does not change the boot sector entry!
 *)
 DoItOldStyle;
{$IFDEF WINDOWS}
 SetErrorMode( oldsettings );
{$ENDIF}
 End ;
{************************************************************
 * Procedure GetDriveName
 *
 * Parameters:
 *	n: the drive number, 1= A:, 2=B: etc.
 *	di: a drive info record that MUST have its flags field 
 *	 already filled by MyGetDriveType!
 * Description:
 *	Tries to obtain the volume info or netshare name for the
 *	passed drive. Default names are used of the info cannot be
 *	safely obtained because the drive handles removable media.
 *
 *Created: 02/26/95 22:22:28 by P. Below
 ************************************************************}
Procedure GetDriveName( n: TDriveNums; Var di: TDriveInfo );
 Begin
 FillChar( di.Info, SIZEOF( di.Info ), 0 );
 If INVALID IN di.Flags Then
 di.DevName[0] := #0
 Else
 If (FLOPPY IN di.Flags) OR (CD_ROM IN di.Flags) Then
 (* don't try To get the volume name For removable media *)
 If (REMOTE IN di.Flags) Then
 StrCopy(di.DevName, ' -UNKNOWN- ')
 Else
 StrCopy(di.Info.volName,' -UNKNOWN- ')
 Else
 If (REMOTE IN di.Flags) Then Begin
 GetNetworkShareName( n, di.DevName );
 If di.DevName[0] = #0 Then
 StrCopy(di.DevName, ' -NETWORK- ')
 End
 Else
 GetDiskInfo( n, di.Info )
 End;
{************************************************************
 * Function GetDiskParameterBlock
 *
 * Parameters:
 *	n: the drive number, 1= A:, 2=B: etc.
 * Returns:
 *	a pointer to the disk parameter bloc, or Nil, if the function
 *	fails.
 * Description:
 *	Uses DOS int 21,ドル function 32ドル. This function fails in network
 *	drives and it tries to actually read the disk. So If you try to
 *	use it on drive that handles removable media, make preparations
 *	to trap critical errors! 
 *
 *Created: 02/26/95 22:33:14 by P. Below
 ************************************************************}
Function GetDiskParameterBlock( drive: TDriveNums ): LP_DPB; Assembler;
 (* return a far pointer to the requested drives disk parameter block.
 This call is appearendly supported by the windows dos extender,
 we get a valid selector back in ds. *)
 Asm
 push ds
 mov DL, drive
 mov AH, 32ドル
{$IFDEF WINDOWS}
 call Dos3Call
{$ELSE}
 int 21ドル
{$ENDIF}
 cmp AL, 0ドルFF
 jne @valid
 (* run into an error somewhere, return nil *)
 xor ax, ax
			mov dx, ax
 jmp @done
 @valid:
 mov ax, bx
 mov dx, ds
 @done:
 pop ds
 End;
{************************************************************
 * Function DriveIsRamdisk
 *
 * Parameters:
 *	n: the drive number, 1= A:, 2=B: etc. MUST be a fixed disk!
 * Returns:
 *	True, if the disk in question has only one FAT copy, False
 *	otherwise.
 * Description:
 *	Tries to read the disks parameter block and checks the number
 *	of FATs present. One FAT is taken to be a sign for a RAM disk.
 *	This check is not bomb-proof! 
 * Error Conditions:
 *	If you call this function for a drive handling removable media,
 *	be prepared to trap critical errors!
 *
 *Created: 02/26/95 22:35:42 by P. Below
 ************************************************************}
Function DriveIsRamdisk( n: TDriveNums ): Boolean;
 Var
 pDPB: LP_DPB;
 Begin
 DriveIsRamdisk := FALSE;
 pDPB := GetDiskParameterBlock( n );
 If pDPB  NIL Then
 If pDPB^.dpbFATCount = 1 Then
 DriveIsRamdisk := TRUE;
 End;
{************************************************************
 * Procedure MyGetDriveType
 *
 * Parameters:
 *	n: the drive number, 1= A:, 2=B: etc. 
 *	f: set of flags that describes the drive filled by this procedure
 * Description:
 *	Tries to determine for the specified drive, whether it is valid,
 *	holds removable media, is remote, remapped, a CD-ROM or RAM-disk.
 *
 *Created: 02/26/95 22:48:32 by P. Below
 ************************************************************}
Procedure MyGetDriveType( n: TDriveNums; Var f: TDTypeSet );
 Var
 dt: word;
 Begin
 f := [];
 Include( f, MediumIsRemovable( n ));
		If ( n=2 ) and DriveIsRemapped( 1 ) Then Begin
		 Include( f, REMAPPED );
		End; { If }
		If not ( INVALID In f ) Then Begin
		 If DriveIsRemote( n ) Then
			 Include( f, REMOTE );
	 If (REMOTE IN f) and DriveIsCDROM( n ) Then
	 Include( f, CD_ROM );
	 If ([HARDDISK, CD_ROM, REMOTE] * f)= [HARDDISK] Then
	 If DriveIsRamdisk( n ) Then
 Include( f, RAMDISK );
		End; { If }
 End;
{************************************************************
 * Procedure GetDriveInfo
 *
 * Parameters:
 *	n: the drive number, 1= A:, 2=B: etc. 
 *	di: record to take the drive type and volume/netshare info
 * Description:
 *	Uses other routines in this Unit do obtain info on the drive
 *	in question. 
 *
 *Created: 02/26/95 22:53:43 by P. Below
 ************************************************************}
Procedure GetDriveInfo( n: TDriveNums; Var di: TDriveInfo );
 Begin
 MyGetDriveType( n, di.Flags );
 GetDriveName( n, di );
 End;
{************************************************************
 * Procedure BuildDriveMap
 *
 * Parameters:
 *	DMap: array of TDriveInfo records to take the info on all
 *	 drives on the system.
 * Description:
 *	Uses other routines from this Unit to build a map of all
 *	drives on the system with drive letters in the range 
 *	A..Z ( logical drives 1..26 ). The map contains for each
 *	drive a set of flags describing the drive type and also,
 * if the drive is valid and does not handle removable media,
 *	the media id info ( volume name, serial number, FAT type ) or
 *	netshare name.
 *
 *Created: 02/26/95 22:55:50 by P. Below
 ************************************************************}
Procedure BuildDriveMap( Var DMap: TDriveMap );
 Var
 n : TDriveNums;
 Begin
 (* build a drive properties map For all possible drives.
 CAVEAT! DR-DOS 6.x has a bug that will fail IOCTL calls For
 drive letters> P:! (Thank's To Ray Tackett [76416,276]
 For this info) *)
 For n := Min_DriveNums To Max_DriveNums Do Begin
 MyGetDriveType( n, DMap[n].Flags );
 GetDriveName( n, DMap[n] );
		End;
 End ;
{************************************************************
 * Function GetLastdrive
 *
 * Parameters:
 *	none
 * Returns:
 *	the logical drive number ( 1=A: etc. ) for the last valid
 *	drive on the system.
 * Description:
 *	Uses DOS int 21,ドル function 0ドルE. On some systems this may just
 *	return the LASTDRIVE setting in CONFIG.SYS!
 *
 *Created: 02/26/95 22:59:12 by P. Below
 ************************************************************}
Function GetLastdrive: TDriveNums; assembler;
	asm
	 mov ah, 19ドル (* get current drive *)
		int 21ドル
	 mov ah, $E (* set current To same *)
		mov dl, al
		int 21ドル (* al returns highest valid drivenumber, 1=A: etc. *)
		sub ah, ah
 End;
End.
{ ------------------------- DEMO PROGRAM ------------------- }
Program DTest;
{$IFDEF WINDOWS}
Uses Drives, WinCRT, Strings;
{$ELSE}
Uses Drives, Strings;
{$ENDIF}
Type
	TypesArray = Array [TDriveTypes] Of String[ 8 ];
Const
	TypeNames: TypesArray =
	 ( 'FLOPPY', 'HARDDISK','REMAPPED','REMOTE','CD_ROM',
 'RAMDISK','INVALID' );
Var
	n: TDriveNums;
	Map: TDriveMap;
	first: Boolean;
	f: TDriveTypes;
Procedure WriteInfo( Const di: TDriveInfo );
	Begin
		If ([ INVALID, CD_ROM, FLOPPY ] * di.Flags ) = [] Then Begin
		 Write( ' ' );
			If not(REMOTE In di.Flags) Then Begin
			 WriteLn( 'Volumen Name: ', StrPas(@di.Info.VolName),
			 ', Serial-No.: ', di.Info.SerialNo,
			 ', FAT-TYpe: ', StrPas(@di.Info.FATType) );
			End { If }
			Else
			 WriteLn( 'Netshare: ', StrPas(@di.DevName));
		End; { If }
	End; { WriteInfo }
Begin
{$IFDEF WINDOWS}
 ScreenSize.Y := 80;
{$ENDIF}
 BuildDriveMap( Map );
	For n := Min_DriveNums To Max_DriveNums Do Begin
	 first := True;
		Write( 'Drive ',Chr( n+Ord( '@' ) ),': [' );
		For f := Low( TDriveTypes ) To High( TDriveTypes ) Do Begin
		 If f in Map[ n ].Flags Then Begin
			 If first Then 
				 first := false
				Else
				 Write( ', ' );
				Write( TypeNames[ f ] );
		 End; { If }
		End; { For }
		WriteLn(']');
		WriteInfo( Map[ n ] );
	End; { For }
	
End.


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