Category : Files from Magazines
Archive   : MAY91.ZIP
Filename : 2N05018A

program access_CD;
var
buf: Ptr (* dummy area to read data into *)
IOErr: integer; (* return from I/O functions *)
refnum: integer;
startTime: longint; (* timer variables, accurate to 1/60 second *)
endTime: longint;
count: longint; (* number of bytes to read or write *)
picsize: longint; (* number of bytes in an "image" *)
sndsize: longint; (* number of bytes in a "sound" *)
wrdsize:longint; (* number of bytes in "text" *)
i: integer; (* ubiquitous counter variable *)
s: string; (* get user input here *)

procedure checkIO; (* did I/O come out OK? *)
begin
if (IOErr <> 0) then
begin
writeln('IOErr = ', IOErr);
halt;
end;
end;

procedure separate; (* access CD as though data is separated *)
var
i: integer;
begin

(* This first read will start CD spinning if it's quiescent *)
IOErr := SetFPos(refnum, fsFromStart, 0);
count := 1024;
IOErr := FSRead(refnum, count, buf);
checkIO;

(* Start the timer *)
startTime := TickCount;
for i := 0 to 9 do
begin
IOErr := SetFPos(refnum, fsFromStart, picsize * i);
checkIO;

count := picsize;
IOErr := FSRead(refnum, count, buf);
checkIO;

(* reposition past the pictures, into the sound area *)
IOErr := SetFPos(refnum, fsFromStart, 10 * picsize + sndsize * i);
checkIO;

count := sndsize;
IOErr := FSRead(refnum, count, buf);
checkIO;

(* reposition past the sounds, into the text area *)
IOErr := SetFPos(refnum, fsFromStart, 10 * (picsize + sndsize)
+ wrdsize * i);
checkIO;

count := wrdsize;
IOErr := FSRead(refnum, count, buf);
checkio;
end;

endTime := TickCount - startTime;
writeln('Separate data areas: ');
writeln('Total time=', endTime / 60 : 9 : 4);
end;

procedure adjacent; (* access CD as though data is adjacent *)
var
i: integer;

begin
(* This first read will start CD spinning if it's quiescent *)
IOErr := SetFPos(refnum, fsFromStart, 0);
checkio;

count := 1024;
IOErr := FSRead(refnum, count, buf);
checkio;

startTime := TickCount;
for i := 0 to 9 do

begin
(* position to the area where combined data begins *)

IOErr := SetFPos(refnum, fsFromStart,
(picsize + wrdsize + sndsize) * i);
checkIO;


count := picsize;
IOErr := FSRead(refnum, count, buf);
checkio;

count := sndsize;
IOErr := FSRead(refnum, count, buf);
checkio;

count := wrdsize;
IOErr := FSRead(refnum, count, buf);
checkio;

end;
endTime := TickCount - startTime;
writeln('Adjacent areas:');
writeln('Total time=', endTime / 60 : 9 : 4);
end;

begin

(* The file named below was one that was big enough to not *)
(* cause positioning errors *)

ioerr := FSOpen('AVCM90AA:AIRC.NDX;1', 0, refnum);
if (ioerr <> 0) then
begin
IOErr := FSClose(refnum);
halt;
end;

count := 200;
count := (count * 1024); (* gives 200K without overflow *)
sndsize := count;
picsize := 65536;
wrdsize := 32768;

(* allocate area to read dummy data into *)
buf := NewPtr(count + picsize + wrdsize);
if (buf = nil) then
halt;

ShowText;

(* Give user a choice of which test to run first; *)
(* this way we can cancel out possible vagaries of *)
(* system caching [which was not enabled during this test] *)
write('Look at CD as separate areas first? (Y/N/Quit) ');
readln(s);
if (s = 'y') or (s = 'Y') then
begin
separate;
adjacent;
end
else if (s = 'n') or (s = 'N') then
begin
adjacent;
separate;
end;
IOErr := FSClose(refnum);
end.