Thread: How to get floppy disk information ?!!

hi guys ..im asking for your help on solving this mind boggling problem ...
you know 2 or 3 month ago i wrote this piece of code in order to get the floppy disk geometry ...and it was as follows:

Code:

//In the name of GOD


#include <conio.h>
#include <stdio.h>
#include <process.h>
#include <dos.h>
#include <stdlib.h>
main(void){
int i,k,start,sector;
char x[512];
clrscr();
gotoxy(27,5);
textcolor(2);
cprintf("In the name of God\n");
gotoxy(22,7);
printf ("First project  Project\n\n");
cprintf ("  This program will show you the information stored on sector 0  of your Floppy disk.\n ");             
printf("     if you are ready press any key to continue ");
for (k=0;k<=4;k++){
delay(500);
cprintf(".");       }
getch();
sector =0;
if (absread (0, 1, sector, &x)!=0){
cprintf ("Error");
exit(1);
}
gotoxy(30,8);
cprintf("Read Successful!\n\n\n");
for (i=0;i<=512;i++)
cprintf("&#37;c",x[i]);
getch();
return 0;
}

after that i see some irrelevant characters on screen ... i just went after it and found some progs and also information concerning FAT
and it was :

Code:

{
  char jumpCode[3];//0 - 2 	Assembly Instruction for jump code.
   char oemName[8];//3 - 10 	OEM Name.
   char bytes_Sector[2];//*11 - 12 	Bytes per sector.
   char sec_Cluster;//13 	Sector per cluster.
   char size_Sector_Reserved[2];//14 - 15 	Number of reserved sector(Boot Sector)
   char fatCount;//16 	Number of File Allocation Table
   char Max_Root_Entry[2];//17 - 18 	Maximum entries possible under root directory.
   char Total_Sector_FS[2];//19 - 20 	Total number of sectors in file system.
   char Media_Type;//21 	Media Type(According to Microsoft 0xf8 for fixed disk and 0xf0 for removable disk.
   char sectors_per_fat[2];//22 - 23 	Sectors allocated for each File allocation table.
   char sectors_per_track[2];//24 - 25 	Sectors per track.
   char total_Head_Count[2];//26 - 27 	Number of head in storage device.
   char no_Sectors_Before_Part[4];//28 - 31 	Number of sectors before start of partition(Not applicable for floppy).
   char no_Sector_FS32[4];//32 - 35 	Number of sectors in file system(32-bit value, not applicable for floppy).
   char BIOS_13h_Drive_No;//36 	BIOS INT13h drive number.
   char reserved;//37 	Not Used.
   char ext_Boot_Part_Signature;//38 	Extended boot signature.
   char vol_Serial_Number[4];//39 - 42 	Volume Serial Number.
   char vol_Lebel_Name[11];//43 - 53 	Volume label in ASCII.
   char FS_Type[8];//54 - 61 	File System Type.
   char boot_Code[448];//62 - 509 	Boot Code, otherwise contains information to replace disk.
   char signature[2];//510 - 511 	Signature for File System.

i just tried to use loops to save the data of the specific regions of the floppy disk on the screen for example i used:

Code:

for(j=0;j<=2;j++)
printf("Assembly instruction for jump code : %C",&x[j])

but again no luck !!
im really confused !!! how to deal with it in C?
(ive already noticed the VC++ equivalent but i have not worked on Vc++ ,so i dont know anything about that ...please tell me and help me on C .... tell me how i can do it under C

oh by the way i was using TC 3 ..thats why it looks ancient ..( im using Pelles C now ..but it seems it doesnt have some header files such as Dos.h ..so i just used TC )

many tanx in advand

I can't help you; this is a question related to hardware much more than it is to C. C is independent of such devices, and looks to the hardware folks to provide the "hook" to query their device for info.

I'd bet $$$ that you could find a program to do this on one of the code depot website, like sourceforge.net, etc.

I'd hate to bet whether the old "DOS" type programs could query the device, in Windows or Linux. DOS was certainly OK with such direct access, but newer OS's may be quite particular about this sort of thing.

In any case, this will bump your question back up to the top of the heap, but sourceforge.net and similar sites, will surely have what you want.

"In the name of GOD" ?? You want to query a floppy drive in the name of God?? I'd change that little line at light speed. You've found a brilliant way to tick off both atheists and believers, at the same time!

How about beginning with telling us which OS you have, then we can advice a suitable compiler and API to use.

Just because your ancient fossil compiler manages to run "hello world" doesn't make it suitable for messing with the hardware at such a low level.

I'm not 100% sure which function(s) you need of these, but I think you can get the relevant info in one of these functions - and it will work under XP. This is a more secure and portable method.

If that fails, you can open the device (A as a file with CreateFile():
http://msdn2.microsoft.com/en-us/library/aa363858.aspx

If you scroll down, there's a section on the "open a physical device" mechanisms. Then read 512 bytes to read a sector, and you should be able to get the disk info you have in the struct. You are "on your own" when you use this sort of mechanism - nothing to prevent you from "getting it wrong".

--
Mats

tanx mat , i ll give it a try .

Ehm, my previous post should have had a link to the volume control functions:
http://msdn2.microsoft.com/en-us/library/aa365730.aspx

You can use all Win32 API functions in C by including the correct header-file, which is specified by each function in the links given - it is USUALLY <windows.h> but some funcitons are in other header files. [Of course, the actual function may be in a different file - but you usually have to include the "main" header file, as the individual functions header file is incomplete and will require other header files to be included first, and which those are and what they are called may change over time, so including the main file is a much better idea].

--
Mats

By the way:

Code:

for(j=0;j<=2;j++)
printf("Assembly instruction for jump code : %C",&x[j])

Not sure what %C does, but I would expect this to print badly if %C is similar to %c - particularly if you take the ADDRESS fo x[j] - as that will not print anything useful. [unless x is a char whose address is at the jump code.]

Unfortunately, searching with google for %C shows up a bunch of %c, so I wasn't able to find the meaning of %C.

The jump code should be 0xE9 0xXX 0x0X where X's are variable depending on exactly where the jump leads. A highly likely scenario is that the 0xE9 0x3E 0x00. Technically, it can also be 0xEB 0xXX, with possibly with a single byte instruction first.

What did you expect this to do?

--
Mats

Yes, using "&#37;02x" should show you the opcode as a two digit number, which is probably the most sensible.

What did you expect it to show, what DOES it show?

--
Mats

Looks like my sig-line is true

But we have no idea what code you ran, or which compiler you were using last (pick one of the ones which isn't TurboC and stick with it for more than 5 minutes).

As it stood, you were just two typo's away from reading the boot sector of A: to writing the boot sector of C:.