Path: utzoo!attcan!uunet!mcvax!unido!fauern!faui44!immd3.informatik.uni-erlangen.de!rtregn
From: rtregn@immd3.informatik.uni-erlangen.de (Robert Regn)
Newsgroups: comp.os.minix
Subject: Re: Fdisk
Message-ID: <810@faui10.informatik.uni-erlangen.de>
Date: 20 Jan 89 19:32:16 GMT
References: <1904@ast.cs.vu.nl>
Organization: IMMD I, University of Erlangen, W-Erlangen
Lines: 147

From article <1904@ast.cs.vu.nl>, by ast@cs.vu.nl (Andy Tanenbaum):
> 
> The fdisk that Robert Regn posted a while back came in here truncated.  Could
> you please post the cdif against 1.3 again.  Has this been thoroughly tested?
> Fdisk is not the kind of program one would like to have bugs in.
> 

For such disks I have a little improved fdisk.c. It's usage is:
		 fdisk [-heads] [/dev/hdx]
The default is -4  and /dev/hd0. It recognizes DOS4 (for 3.3) and
Xenix partitions also.

I have used it several times. The changes are not great so I think it has no
bugs - and it prints the number of heads for your check.

A good improvement would be to print the partitions in the same order as
they are mapped by the disk driver into /dev/hd[1-4]. So the danger destroying
another filesystem with mkfs is reduced.

*** minix/1.3/a.fertig/commands/fdisk.c	Tue Oct  4 12:43:10 1988
--- FDISK.C	Tue Dec  6 16:53:34 1988
***************
*** 55,61 ****
--- 55,64 ----
  char	secbuf[SECSIZE];
  char	*devname;
  char	*dosstr  = "  DOS  ";
+ char	*dosstr4 = " DOS  4";
  char	*ndosstr = "Non-DOS";
+ char	*xenstr = " Xenix ";
+ int heads;
  
  #ifdef DOS
  union	REGS	regs;
***************
*** 75,86 ****
  
  	/* init */
  
! 	if (argc != 2) {
! 		printf("Usage: fdisk /dev/hdx\n");
  		exit(1);
  	}
  
! 	devname = argv[1];
  	getboot(secbuf);	/* get boot sector	*/
  
  	do {
--- 78,99 ----
  
  	/* init */
  
! 	if (  argc > 1 && (*++argv)[0] == '-')		/*flag*/
! 		{heads = atoi( & (*argv)[1]);
! 		 printf("heads: %d	", heads);
! 		 argv++;
! 		 argc--;
! 		}
! 	else	heads = NHEAD;
! 
! 	if (argc > 2) {
! 		printf("Usage: fdisk [-heads] [/dev/hdx]\n");
  		exit(1);
  	}
  
! 	if ( argc == 1)
! 		devname = "/dev/hd0";
! 	else	devname = *argv;
  	getboot(secbuf);	/* get boot sector	*/
  
  	do {
***************
*** 339,346 ****
  
  	if (entry->sysind == 0x01)
  		typestring = dosstr;
! 	else
! 		typestring = ndosstr;
  	printf("%5d         %s  ",number,typestring);
  	temp = entry->start_sec & 0xc0;
  	low_cyl = (entry->start_cyl & 0xff) + (temp << 2);
--- 352,363 ----
  
  	if (entry->sysind == 0x01)
  		typestring = dosstr;
! 	else	if (entry->sysind == 0x02)
! 		typestring = xenstr;
! 	else	if (entry->sysind == 0x04)
! 		typestring = dosstr4;
! 		else
! 			typestring = ndosstr;
  	printf("%5d         %s  ",number,typestring);
  	temp = entry->start_sec & 0xc0;
  	low_cyl = (entry->start_cyl & 0xff) + (temp << 2);
***************
*** 423,432 ****
  {
  	int	bigcyl;
  
! 	bigcyl = logsec / (NHEAD * NSEC);
  	*sec = (logsec % NSEC) + 1 + ((bigcyl >> 2) & 0xc0);
  	*cyl = bigcyl & 0xff;
! 	*hd = (logsec % (NHEAD * NSEC)) / NSEC;
  }
  
  /*
--- 440,449 ----
  {
  	int	bigcyl;
  
! 	bigcyl = logsec / (heads * NSEC);
  	*sec = (logsec % NSEC) + 1 + ((bigcyl >> 2) & 0xc0);
  	*cyl = bigcyl & 0xff;
! 	*hd = (logsec % (heads * NSEC)) / NSEC;
  }
  
  /*
***************
*** 487,497 ****
  		return;
  	}
  	low = first & 0xffff;
! 	low = low * NSEC * NHEAD;
  	if (low == 0)
  		low = 1; /* sec0 is master boot record */
  	high = last & 0xffff;
! 	high = (high + 1)*NSEC*NHEAD - 1;
  	entry->lowsec = low;
  	entry->size = high - low + 1;
  	sec_to_hst(low,
--- 504,514 ----
  		return;
  	}
  	low = first & 0xffff;
! 	low = low * NSEC * heads;
  	if (low == 0)
  		low = 1; /* sec0 is master boot record */
  	high = last & 0xffff;
! 	high = (high + 1)*NSEC*heads - 1;
  	entry->lowsec = low;
  	entry->size = high - low + 1;
  	sec_to_hst(low,
-------------------------------------------------

Robert Regn	
rtregn@faui32.uucp
rtregn@immd3.informatik.uni-erlangen.de			West Germany