This is the ORIGINAL source code (in C) for the
1989 hard disk editor, capable of editing a
FAT32 hard disk under Windows 98:

================
5. Advice Needed
================
Could anyone be kind and please take a look at
the code - and tell me exactly what I should add
to it in order to make it perform its intended
purpose ?

Appreciate any help,
Thanks a lot,
Dan Richardson

==================================================

Following is the Hard Disk Sector Editor's
C source code:
==============
A. All original files appear here with their
   filenames, which include:
   - DISKEDIT.C
   - DEFILES.C
   - DEFILES.H
   - DEVIDEO.C
   - DEVIDEO.H
   - DISKS.C
   - DISKS.H
   - KEYS.C
   - KEYS.H
   - VIDEO.C
   - VIDEO.H

B. ...
   ...
   ...

==================================================

filename: DISKEDIT.C   (an original file)
____________________
/* diskedit.c - low level disk sector viewer/editor */
/* lrs - 2/13/89 */

#include <stdio.h>
#include <bios.h>
#include <dos.h>
#include "disks.h"
#include "video.h"
#include "keys.h"
#include "devideo.h"
#include "defiles.h"

#define FALSE 0
#define TRUE  ~FALSE

char WriteAllowed = FALSE;
int Drive = 0x80;
int HalfDisp = TRUE; int DispOffs = 0;

int Cyl = 0; int Head = 0; int Sec = 1;
int MaxCyl, MaxHead, MaxSec;
int scrrows;
char Done;
unsigned char SecBuf[BYTESPERSECTOR];

==================================================
filename: DEFILES.C   (an original file)
____________________
/* defiles.c - disk file read/write for diskedit.c */
/* lrs - 2/13/89 */

#include <stdio.h>
#include "disks.h"   /* for BYTESPERSECTOR */
#include "devideo.h" /* for error messages */
#include "defiles.h"
/*-----------------------------------------------------------------------*/
void ReadFile (char filename[], void* buf)
  { /* Read a binary data file into the sector buffer */
  FILE* fin;

  if ((fin = fopen(filename,"rb")) == NULL)
    ErrorMessage("File Not Found");
  if (fread(buf, BYTESPERSECTOR, 1, fin) != 1)
    ErrorMessage("Error Reading File");
  if (fclose(fin))
    ErrorMessage("Error Closing File");
  }    /* GetFile */

/*-----------------------------------------------------------------------*/
void WriteFile (char filename[], void* buf)
  { /* Save the sector buffer as a binary file */
  FILE* fout;

  if ((fout = fopen(filename,"wb")) == NULL)
    ErrorMessage("File Creation Error");
  else if (fwrite(buf, BYTESPERSECTOR, 1, fout) != 1)
    ErrorMessage("Error Writing File");
  else if (fclose(fout))
    ErrorMessage("Error Closing File");
  }    /* GetFile */

==================================================
filename: DEFILES.H   (an original file)
____________________
/* defiles.h - lrs - 2/13/89 */
void ReadFile (char filename[], void* buf);
void WriteFile (char filename[], void* buf);

/*---- end of defiles.h ----*/
==================================================
filename: DEVIDEO.C   (an original file)
____________________
/* devideo.c - special video routines for diskedit.c */
/* lrs - 2/13/89 */

#include "video.h"

void ErrorMessage(char mess[])
  {
  at(screenrows()-1,0);
  cprintf(mess);
  cleareol();
  }    /* ErrorMessage */

void ClearErrorMessage()
  {
  at(screenrows()-1,0);
  cleareol();
  }    /* ClearErrorMessage */

void ShowWriteAllowed(int writeallowed)
  {
  at(14,0);
  if (writeallowed)
    cprintf("Write Ok  ");
  else
    cprintf("Write Prot");
  }

void DisplayFrame()
  {
  int ct, linect;

  in(REVERSE); at(0,79-42);
  cprintf(" Laine's Mighty Disk Editor  v0.0 02/13/89 ");
  in(DIM);
  at(2,0); cprintf("  CURRENT");
  at(3,0); cprintf("Drive:");
  at(4,0); cprintf("  Cyl:");
  at(5,0); cprintf(" Head:");
  at(6,0); cprintf("  Sec:");
  at(8,0); cprintf("  MAXIMUM");
  at(9,0); cprintf("  Cyl:");
  at(10,0); cprintf(" Head:");
  at(11,0); cprintf("  Sec:");
  ShowWriteAllowed(0);
  at(1,11);
  cprintf("?????");
  at(2,11);
  cprintf("??1 0  1  2  3  4  5  6  7  8  9  A  B  C  D  E
Fo0123456789ABCDEFo");
  at(3,11);
  cprintf("??1");
  linect = (screenrows() >= 43) ? 32 : 16;
  for (ct = 0; ct < linect; ct++)
    {
    at(ct+4,11);
    cprintf("o  o                       -                       o    
          o");
    }
  at(ct+4,11);
  cprintf("?");
  at(ct+5,4); in(NORMAL);
  cprintf("PgUp/PgDn - Prev/Next Sector,  F10 Updates Sector (alt+F10
enables update)");
  at(ct+6,2);
  cprintf("G - Goto Sec, M - Modify byte, R/W - Read/Write Sec to/from
File, ESC to quit");
  } /* DisplayFrame */
/*-----------------------------------------------------------------------*/
void ShowMaxes(int maxcyl, int maxhead, int maxsec)
  {
  in(DIM);
  at(9,7); cprintf("%3d",maxcyl);
  at(10,7); cprintf("%3d",maxhead);
  at(11,7); cprintf("%3d",maxsec);
  }
/*-----------------------------------------------------------------------*/
void DisplaySector (int drive, int cyl, int head, int sec,
                    void* buf, int offs)
  {
  int ct, linect;
  at(3,8); cprintf("%02x",drive);
  at(4,7); cprintf("%3d",cyl);
  at(5,7); cprintf("%3d",head);
  at(6,7); cprintf("%3d",sec);
  linect = (screenrows() >= 43) ? 32 : 16;
  buf += offs*16;
  for(ct = 0;  ct < linect; ct++)
    {
    at(ct+4,12); in(DIM); cprintf("%02X",ct+offs);
    at(ct+4,15); in(NORMAL);
    Write16Bytes(buf);
    buf+=16;
    }    /* for(ct = 0  to linect */
  at(screenrows()-2,0);
  } /* DisplaySector */

/*---- end of devideo.c ----*/
==================================================
filename: DEVIDEO.H   (an original file)
____________________
/* devideo.h - lrs - 2/13/89 */
void ErrorMessage(char mess[]);
void ClearErrorMessage();
void ShowWriteAllowed(int writeallowed);
void DisplayFrame();
void ShowMaxes(int maxcyl, int maxhead, int maxsec);
void DisplaySector (int drive, int cyl, int head, int sec,
                    void* buf, int offs);
/*---- end of devideo.h ----*/
==================================================
filename: DISKS.C   (an original file)
____________________
/* disks.c - interface to IBM ROM BIOS disk routines */
/* lrs 2/13/89 */

#include <bios.h>
#include <dos.h>
#include "disks.h"

void InitDisks()
  { /* ROM BIOS "Reset Disks" command */
  union REGS reg;
  reg.x.ax = 0;
  int86(0x13,?,?);
  }    /* InitDisks */
/*-----------------------------------------------------------------------*/
void GetDiskParams(int drive, int* maxcyl, int* maxhead, int* maxsec)
  { /* get size of disk */
    /* (note: this (and the rest) assumes 512 byte sectors */
  union REGS reg;
  reg.h.ah = 8;
  reg.h.dl = drive;
  int86(0x13,?,?);
  *maxcyl = reg.h.ch + ((reg.h.cl & 0xC0) << 2);
  *maxhead = reg.h.dh;
  *maxsec = reg.h.cl & 0x3F;
  }    /* GetDiskParameters */
/*-----------------------------------------------------------------------*/
int ReadSector (int drive, int cyl, int head, int sec, void far* buf)
  { /* read a 512 byte sector from phys location on disk */
    /* return TRUE if success */
  union REGS reg;
  struct SREGS sreg;

  int retry = 3;;
  do {
    reg.x.ax = 0x0201;
    reg.x.bx = FP_OFF(buf);
    sreg.es = FP_SEG(buf);
    reg.h.ch = cyl & 0xFF;
    /* top two bits (8 & 9) of cyl # hidden in bits 6 & 7 of sector */
    reg.h.cl = sec | ((cyl >> 2) & 0xC0);
    reg.h.dh = head;
    reg.h.dl = drive;
    int86x(0x13,?,?,&sreg);
    } while ((reg.x.cflag) && (retry-- > 0));
  return(reg.x.cflag == 0);
  }   /* ReadSector */
/*-----------------------------------------------------------------------*/
int WriteSector (int drive, int cyl, int head, int sec, void far* buf)
  { /* write memory block to specified physical sector on disk */
    /* return TRUE if success */
  union REGS reg;
  struct SREGS sreg;
  int retry = 3;

    do {
      reg.x.ax = 0x0301;
      reg.x.bx = FP_OFF(buf);    /* THIS MUST BE FIXED !!!! */
      sreg.es = FP_SEG(buf);
      reg.h.ch = cyl & 0xFF;
      /* top two bits (8 & 9) of cyl # hidden in bits 6 & 7 of sector
*/
      reg.h.cl = sec | ((cyl >> 2) & 0xC0);
      reg.h.dh = head;
      reg.h.dl = drive;
      int86x(0x13,?,?,&sreg);
      } while ((reg.x.cflag) && (retry-- > 0));
    return(reg.x.cflag == 0);
  }   /* WriteSector */

/*---- end of disks.c ----*/
==================================================
filename: DISKS.H   (an original file)
____________________
/* disks.h - lrs 2/13/89 */
#define BYTESPERSECTOR 512

void InitDisks(void);
void GetDiskParams(int drive, int* maxcyl, int* maxhead, int* maxsec);
int ReadSector (int drive, int cyl, int head, int sec, void far* buf);
int WriteSector (int drive, int cyl, int head, int sec, void far*
buf);

/*---- end of disks.h ----*/
==================================================
filename: KEYS.C   (an original file)
____________________
/* keys.c - keyboard input and function key translation */
/* lrs - 2/13/89 */

#include <stdio.h>
#include <bios.h>
#include <ctype.h>
#include "keys.h"
#include "video.h"
/*-----------------------------------------------------------------------*/
int getcmd(void)
  {
  int ch;

  ch = bioskey(0);
  if ((ch & 0xFF) !=0) /* not a function key */
    {
    ch &= 0xFF;
    return (toupper(ch));
    }
  else
    return(ch);
  }    /* getcmd */
/*-----------------------------------------------------------------------*/
unsigned char getkey(char prompt[])
  {
  unsigned char ch;

Read:

http://www.angelfire.com/ms3/bchambless0/welcome_to_clc.html

Usually means you're not properly specifying the include file directory
to the compiler. You're going dig into your compiler options to find that.
(Command line compilers usually have a "-Idir" or "-I dir" option, but it
varies.)

#    - DISKEDIT.C

That appears to be truncated. You may have to check the source distribution.

In the PC market, 14 years is very old. Unless your hardware and operating
system are of the same vintage, the program might not work, or do worse
than not working. My inclination would be to study the program and the
system interfaces, and then rewrite the edittor. However all I/O to the
raw device rather than through a file is perilous, and you can end up losing
everything on that disk drive.