Title: 3 Drive related Functions
Question: Check for Drive A
Get Drive information
Get Driver Serial#
Answer:
//// Check if there is a disk in drive A silently
When your program accesses drive 'A', it would be handy to intercept the
'Drive Not Ready' system error message. You can create your own generic
function to test any drive letter.
function DiskInDrive(Drive: Char): Boolean;
var
ErrorMode: word;
begin
Drive: = UpCase(Drive);
if not (Drive in ['A'..'Z']) then
raise EConvertError.Create('Not a valid drive ID');
ErrorMode := SetErrorMode(SEM_FailCriticalErrors);
try
if DiskSize(Ord(Drive) - $40) = -1 then
DiskInDrive := False
else
DiskInDrive := True;
finally
SetErrorMode(ErrorMode);
end;
end;
Your function forces the passed drive letter to uppercase and assures it is
a valid drive. Then you turn off the system error reporting and perform a
disk operation. Your function will return True indicating the disk is
present or False if there was an error. The last bit of housekeeping is to
turn on the system error reporting.
///// How to get drive information
Procedure Drives;
var
Drive: Char;
DriveLetter: String[4];
li : TListItem;
iSPC, iBPS, iFC, iTC : integer;
bDataOK : boolean;
sDriveType, sStatus : string;
begin
for Drive := 'A' to 'Z' do
begin
DriveLetter := Drive + ':\';
bDataOK := GetDiskFreeSpace(PChar(Drive + ':\'), iSPC, iBPS, iFC, iTC);
sDriveType := '';
case GetDriveType(PChar(Drive + ':\')) of
DRIVE_REMOVABLE: sDriveType := 'Floppy';
DRIVE_FIXED: sDriveType := 'Fixed';
DRIVE_REMOTE: sDriveType := 'Network';
DRIVE_CDROM: sDriveType := 'CD-ROM';
end;
if sDriveType '' then
begin
sDriveType := sDriveType + ' Drive ';
if bDataOK then
sStatus := Format('%.2fMB, %.2fMB Free', [iSPC * 1.0 * iBPS * iTC / 1024.0 / 1024.0, iSPC * 1.0 * iBPS * iFC / 1024.0 / 1024.0])
else
sStatus := '';
li := lv.Items.Add;
li.Caption := Format('Drive %s:', [Drive]);
li.SubItems.Add(sDriveType + sStatus);
end;
end;
end;
///// Get Drive Serial Number
type
MIDPtr = ^MIDRec;
MIDRec = Record
InfoLevel: word;
SerialNum: LongInt;
VolLabel: Packed Array [0..10] of Char;
FileSysType: Packed Array [0..7] of Char;
end;
var
Info: MIDRec;
function GetDriveSerialNum(MID: MIDPtr; drive: Word): Boolean; assembler;
asm
push DS { Just for safety, I dont think its really needed }
mov ax,440Dh { Function Get Media ID }
mov bx,drive { drive no (0-Default, 1-A ...) }
mov cx,0866h { category and minor code }
lds dx,MID { Load pointeraddr. }
call DOS3Call { Supposed to be faster than INT 21H }
jc @@err
mov al,1 { No carry so return TRUE }
jmp @@ok
@@err:
mov al,0 { Carry set so return FALSE }
@@ok:
pop DS { Restore DS, were not supposed to change it }
end;
{To read the Serial Number}
function ReadSerial:string;
begin
if GetDriveSerialNum(@info,0) then
Result := IntToStr(info.SerialNum);
end;
{To read the Vol Label}
function ReadVol:string;
begin
if GetDriveSerialNum(@info,0) then
Result := StrPas(Info.VolLabel);
end;