Import Dev86src-0.15.3.tar.gzv0.15.3

4 files changed, 591 insertions, 165 deletions

diff --git a/bootblocks/makeboot.c b/bootblocks/makeboot.c
index e45fa4a..77403c3 100644
--- a/bootblocks/makeboot.c
+++ b/bootblocks/makeboot.c
@@ -17,11 +17,11 @@
 unsigned char buffer[1024];
 
 #define FS_NONE	0	/* Bootsector is complete */
-#define FS_ADOS	1	/* Bootsector needs 'normal' DOS FS */
-#define FS_DOS	2	/* Bootsector needs any DOS FS */
+#define FS_DOS	1	/* Bootsector needs 'normal' DOS FS */
+#define FS_ADOS	2	/* Bootsector likes any DOS FS */
 #define FS_TAR	3	/* Bootsector needs GNU-tar volume label */
-#define FS_STAT	4	/* DOS bootsector is checked */
-#define FS_ZERO 5	/* Boot sector must be Zapped */
+#define FS_STAT	4	/* Any bootsector is checked */
+#define FS_ZERO 5	/* Boot sector must be already Zapped */
 #define FS_MBR  6	/* Boot sector is an MBR */
 
 #ifndef __MSDOS__
@@ -40,29 +40,35 @@ struct bblist {
 } bblocks[] = {
 { "tar",  "Bootable GNU tar volume lable",
    	   tarboot_data, tarboot_size, 0, 0, 		FS_TAR},
-{ "dosfs","Boot file BOOTFILE.SYS from dos floppy",
+{ "dos12","Boot file BOOTFILE.SYS from dos floppy",
            msdos_data, msdos_size,
 	   1, msdos_boot_name-msdos_start,		FS_DOS, 12},
-{ "dos16","Boot file BOOTFILE.SYS from 16 bit dos filesystem",
+{ "dos16","Boot file BOOTFILE.SYS from FAT16 hard disk or floppy",
            msdos16_data, msdos16_size,
 	   1, msdos16_boot_name-msdos16_start,		FS_DOS, 16},
-{ "none", "No OS bootblock, just message",  
+{ "none", "No OS bootblock, just display message",  
            noboot_data, noboot_size, 
-	   2, noboot_boot_message-noboot_start, 	FS_DOS},
+	   2, noboot_boot_message-noboot_start, 	FS_ADOS},
 { "skip", "Bypasses floppy boot with message",  
            skip_data, skip_size,  
-	   2, skip_mesg-skip_start,			FS_DOS},
+	   2, skip_mesg-skip_start,			FS_ADOS},
 { "minix","Minix floppy FS booter",           
            minix_data, minix_size, 
 	   2, minix_bootfile-minix_start,		FS_ZERO},
 { "hdmin","Minix Hard disk FS booter",    
            minixhd_data, minixhd_size, 
 	   2, minixhd_bootfile-minixhd_start,		FS_ZERO},
+#ifdef mbr_Banner
+{ "mbr",  "Master boot record for HD (with optional message)",             
+           mbr_data,mbr_size, 
+	   2, mbr_Banner-mbr_start, 			FS_MBR},
+#else
 { "mbr",  "Master boot record for HD",             
            mbr_data,mbr_size, 0, 0, 			FS_MBR},
+#endif
 { "stat", "Display dosfs superblock",                          
            0, 0, 0, 0, 					FS_STAT},
-{ "copy", "Copy boot block to makeboot.sav",                   
+{ "copy", "Copy boot block to makeboot.sav or named file",                   
            0, 0, 0, 0, 					FS_STAT},
 { "Zap",  "Clear boot block to NULs",                       
            0, 1024, 0, 0, 				FS_NONE},
@@ -121,9 +127,10 @@ char ** argv;
    switch(ptr->fstype)
    {
    case FS_NONE:	/* override */
-   	break;
-   case FS_DOS:
    case FS_STAT:
+   case FS_ADOS:
+      break;
+   case FS_DOS:
       check_msdos();
       if(ptr->fsmod) check_simpledos(ptr->fsmod);
       break;
@@ -145,12 +152,14 @@ char ** argv;
    switch(ptr->fstype)
    {
    case FS_STAT:
-      print_super(buffer);
       if( strcmp(ptr->name, "copy") == 0 )
          save_super(buffer);
+      else
+         print_super(buffer);
       close_disk();
       exit(0);
    case FS_DOS:
+   case FS_ADOS:
       for(i=0; i<sysboot_dosfs_stat; i++)
          buffer[i] = ptr->data[i];
       for(i=sysboot_codestart; i<512; i++)
@@ -186,7 +195,7 @@ char ** argv;
       set_asciz(ptr->boot_name);
       break;
    default:
-      fprintf(stderr, "Cannot specify boot file for this block\n");
+      fprintf(stderr, "Cannot specify boot name for this block\n");
       exit(1);
    }
 
@@ -212,11 +221,12 @@ Usage()
       progname = "makeboot";
 
 #ifdef __MSDOS__
-   fprintf(stderr, "Usage: %s [-f] bootblock[=bootname] a:\n", progname);
+   fprintf(stderr, "Usage: %s [-f] bootblock[=bootname] a:\n\n", progname);
+   fprintf(stderr, "The 'a:' can be any drive or file or @: for the MBR.\n");
 #else
-   fprintf(stderr, "Usage: %s [-f] bootblock[=bootname] /dev/fd0\n", progname);
+   fprintf(stderr, "Usage: %s [-f] bootblock[=bootname] /dev/fd0\n\n", progname);
 #endif
-   fprintf(stderr, "\nThe bootname is a filename to use with the block,\n");
+   fprintf(stderr, "The bootname is a filename or message to use with the block,\n");
    fprintf(stderr, "the blocks are:\n");
    for(;ptr->name; ptr++)
        fprintf(stderr, "\t%s\t%s\n", ptr->name, ptr->desc);
@@ -233,14 +243,22 @@ char * diskname;
    /* Freedos fix */
    if( diskname[2] == '\r' ) diskname[2] = 0;
 
-   if( strcmp("a:", diskname) == 0 ) { disktype = 1; return 0; }
-   if( strcmp("b:", diskname) == 0 ) { disktype = 2; return 0; }
-   if( strcmp("A:", diskname) == 0 ) { disktype = 1; return 0; }
-   if( strcmp("B:", diskname) == 0 ) { disktype = 2; return 0; }
+   if( diskname[2] == 0 && diskname[1] == ':' )
+   {
+      if (isalpha(diskname[0])) {
+	 disktype = toupper(diskname[0])-'A'+1;
+	 return 0;
+      }
+      if (diskname[0] =='@') {
+	 disktype = 129;
+	 return 0;
+      }
+   }
 #endif
    disktype = 0;
-   diskfd = fopen(diskname, "r+");
-   if( diskfd == 0 ) diskfd = fopen(diskname, "r");
+   diskfd = fopen(diskname, "r+b");
+   if( diskfd == 0 ) diskfd = fopen(diskname, "rb");
+   if( diskfd == 0 && force ) diskfd = fopen(diskname, "w+b");
    if( diskfd == 0 )
    {
       fprintf(stderr, "Cannot open '%s'\n", diskname);
@@ -262,7 +280,7 @@ int sectno;
 char * loadaddr;
 {
 #ifdef __MSDOS__
-   if( disktype == 1 || disktype == 2 )
+   if( disktype == 1 || disktype == 2 || disktype == 129 )
    {
       int tries, rv;
       int s,h,c;
@@ -271,11 +289,29 @@ char * loadaddr;
       c = sectno/disk_sect/disk_head;
 
       for(tries=0; tries<6; tries++)
-         if( (rv = dos_sect_write(disktype-1, c, h, s, loadaddr)) == 0 )
+         if( (rv = bios_sect_write(disktype-1, c, h, s, loadaddr)) == 0 )
+            break;
+      if( rv )
+      {
+	 if (rv/256 == 3)
+	    fprintf(stderr, "Write protect error writing sector %d\n", sectno);
+	 else
+	    fprintf(stderr, "Error writing sector %d, (%d)\n", sectno, rv/256);
+	 return -1;
+      }
+      return 0;
+   }
+   if( disktype )
+   {
+      int tries, rv;
+
+      for(tries=0; tries<6; tries++)
+         if( (rv = dos_sect_write(disktype-1, sectno, loadaddr)) == 0 )
             break;
       if( rv )
       {
-         fprintf(stderr, "Error writing sector %d, (%d)\n", sectno, rv/256);
+         fprintf(stderr, "Error writing sector %d, (0x%04d)\n", sectno, rv);
+         memset(loadaddr, '\0', 512);
 	 return -1;
       }
       return 0;
@@ -303,7 +339,7 @@ char * loadaddr;
 {
    int cc;
 #ifdef __MSDOS__
-   if( disktype == 1 || disktype == 2 )
+   if( disktype == 1 || disktype == 2 || disktype == 129 )
    {
       int tries, rv;
       int s,h,c;
@@ -312,7 +348,7 @@ char * loadaddr;
       c = sectno/disk_sect/disk_head;
 
       for(tries=0; tries<6; tries++)
-         if( (rv = dos_sect_read(disktype-1, c, h, s, loadaddr)) == 0 )
+         if( (rv = bios_sect_read(disktype-1, c, h, s, loadaddr)) == 0 )
             break;
       if( rv )
       {
@@ -322,6 +358,21 @@ char * loadaddr;
       }
       return 0;
    }
+   if( disktype )
+   {
+      int tries, rv;
+
+      for(tries=0; tries<6; tries++)
+         if( (rv = dos_sect_read(disktype-1, sectno, loadaddr)) == 0 )
+            break;
+      if( rv )
+      {
+         fprintf(stderr, "Error reading sector %d, (0x%04d)\n", sectno, rv);
+         memset(loadaddr, '\0', 512);
+	 return -1;
+      }
+      return 0;
+   }
 #endif
    if( disktype )
    {
@@ -337,10 +388,11 @@ char * loadaddr;
    }
    return 0;
 }
+
 /**************************************************************************/
 
 #ifdef __MSDOS__
-dos_sect_read(drv, track, head, sector, loadaddr)
+bios_sect_read(drv, track, head, sector, loadaddr)
 {
 #asm
   push	bp
@@ -349,26 +401,24 @@ dos_sect_read(drv, track, head, sector, loadaddr)
   push	ds
   pop	es
 
-  mov	dh,[bp+2+_dos_sect_read.head]
-  mov	dl,[bp+2+_dos_sect_read.drv]
-  mov	cl,[bp+2+_dos_sect_read.sector]
-  mov	ch,[bp+2+_dos_sect_read.track]
+  mov	dh,[bp+2+_bios_sect_read.head]
+  mov	dl,[bp+2+_bios_sect_read.drv]
+  mov	cl,[bp+2+_bios_sect_read.sector]
+  mov	ch,[bp+2+_bios_sect_read.track]
 
-  mov	bx,[bp+2+_dos_sect_read.loadaddr]
+  mov	bx,[bp+2+_bios_sect_read.loadaddr]
 
   mov	ax,#$0201
   int	$13
-  jc	read_err
+  jc	bios_read_err
   mov	ax,#0
-read_err:
+bios_read_err:
 
   pop	bp
 #endasm
 }
-#endif
 
-#ifdef __MSDOS__
-dos_sect_write(drv, track, head, sector, loadaddr)
+bios_sect_write(drv, track, head, sector, loadaddr)
 {
 #asm
   push	bp
@@ -377,18 +427,18 @@ dos_sect_write(drv, track, head, sector, loadaddr)
   push	ds
   pop	es
 
-  mov	dh,[bp+2+_dos_sect_write.head]
-  mov	dl,[bp+2+_dos_sect_write.drv]
-  mov	cl,[bp+2+_dos_sect_write.sector]
-  mov	ch,[bp+2+_dos_sect_write.track]
+  mov	dh,[bp+2+_bios_sect_write.head]
+  mov	dl,[bp+2+_bios_sect_write.drv]
+  mov	cl,[bp+2+_bios_sect_write.sector]
+  mov	ch,[bp+2+_bios_sect_write.track]
 
-  mov	bx,[bp+2+_dos_sect_write.loadaddr]
+  mov	bx,[bp+2+_bios_sect_write.loadaddr]
 
   mov	ax,#$0301
   int	$13
-  jc	write_err
+  jc	bios_write_err
   mov	ax,#0
-write_err:
+bios_write_err:
 
   pop	bp
 #endasm
@@ -397,6 +447,112 @@ write_err:
 
 /**************************************************************************/
 
+#ifdef __MSDOS__
+
+/* All this mess just to read one sector!! */
+
+struct disk_packet {
+   long	sector;
+   int	count;
+   long	addr;
+} disk_packet;
+
+dos_sect_read(drv, sector, loadaddr)
+{
+#asm
+  push	bp
+  mov	bp,sp
+
+  mov	al,[bp+2+_dos_sect_read.drv]
+  mov	cx,#1
+  mov	dx,[bp+2+_dos_sect_read.sector]
+  mov	bx,[bp+2+_dos_sect_read.loadaddr]
+
+  int	$25
+  pop	bx
+  jnc	dos_read_ok
+
+  mov	bp,sp
+
+  ! Fill the disk packet
+  mov	ax,[bp+2+_dos_sect_read.sector]
+  mov	[_disk_packet],ax
+  xor	ax,ax
+  mov	[_disk_packet+2],ax
+  inc	ax
+  mov	[_disk_packet+4],ax
+  mov	ax,[bp+2+_dos_sect_read.loadaddr]
+  mov	[_disk_packet+6],ax
+  mov	ax,ds
+  mov	[_disk_packet+8],ax
+
+  mov	dl,[bp+2+_dos_sect_read.drv]
+  inc	dl
+  mov	bx,#_disk_packet
+  mov	cx,#0xFFFF
+  mov	si,#0
+  mov	ax,#0x7305
+
+  int	$21
+
+  jc	dos_read_err
+dos_read_ok:
+  mov	ax,#0
+dos_read_err:
+
+  pop	bp
+#endasm
+}
+
+dos_sect_write(drv, sector, loadaddr)
+{
+#asm
+  push	bp
+  mov	bp,sp
+
+  mov	al,[bp+2+_dos_sect_write.drv]
+  mov	cx,#1
+  mov	dx,[bp+2+_dos_sect_write.sector]
+  mov	bx,[bp+2+_dos_sect_write.loadaddr]
+
+  int	$26
+  pop	bx
+  jnc	dos_write_ok
+
+  mov	bp,sp
+
+  ! Fill the disk packet
+  mov	ax,[bp+2+_dos_sect_write.sector]
+  mov	[_disk_packet],ax
+  xor	ax,ax
+  mov	[_disk_packet+2],ax
+  inc	ax
+  mov	[_disk_packet+4],ax
+  mov	ax,[bp+2+_dos_sect_write.loadaddr]
+  mov	[_disk_packet+6],ax
+  mov	ax,ds
+  mov	[_disk_packet+8],ax
+
+  mov	dl,[bp+2+_dos_sect_write.drv]
+  inc	dl
+  mov	bx,#_disk_packet
+  mov	cx,#0xFFFF
+  mov	si,#1
+  mov	ax,#0x7305
+
+  int	$21
+
+  jc	dos_write_err
+dos_write_ok:
+  mov	ax,#0
+dos_write_err:
+
+  pop	bp
+#endasm
+}
+#endif
+/**************************************************************************/
+
 check_zapped()
 {
    int i;
@@ -551,12 +707,21 @@ copy_tarblock()
 #define DOS_SPT		9
 #define DOS_HEADS	10
 #define DOS_HIDDEN	11
+
 #define DOS4_MAXSECT	12
 #define DOS4_PHY_DRIVE	13
 #define DOS4_SERIAL	14
 #define DOS4_LABEL	15
 #define DOS4_FATTYPE	16
 
+#define DOS7_MAXSECT	17
+#define DOS7_FAT32LEN	18
+#define DOS7_FLAGS	19
+#define DOS7_VERSION	20
+#define DOS7_ROOT_CLUST	21
+#define DOS7_INFO_SECT	22
+#define DOS7_BOOT2	23
+
 struct bootfields {
    int offset;
    int length;
@@ -577,11 +742,21 @@ struct bootfields {
    { 0x18, 2, 0},
    { 0x1A, 2, 0},
    { 0x1C, 4, 0},
-   { 0x20, 4, 0},
+
+   { 0x20, 4, 0},	/* DOS4+ */
    { 0x24, 1, 0},
    { 0x27, 4, 0},
    { 0x2B, 11, 0},
    { 0x36, 8, 0},
+
+   { 0x20, 4, 0},	/* DOS7 FAT32 */
+   { 0x24, 4, 0},
+   { 0x28, 2, 0},
+   { 0x2A, 2, 0},
+   { 0x2C, 4, 0},
+   { 0x30, 2, 0},
+   { 0x32, 2, 0},
+
    { -1,0,0}
 };
 
@@ -595,24 +770,39 @@ static char * fieldnames[] = {
    "Reserved sectors",
    "FAT count",
    "Root dir entries",
-   "Sector count (=0 if large FS)",
+   "Sector count",
    "Media code",
    "FAT length",
    "Sect/Track",
    "Heads",
    "Hidden sectors (Partition offset)",
+
    "Large FS sector count",
    "Phys drive",
    "Serial number",
    "Disk Label (DOS 4+)",
    "FAT type",
+
+   "FAT32 FS sector count",
+   "FAT32 FAT length",
+   "FAT32 Flags",
+   "FAT32 version",
+   "FAT32 Root Cluster",
+   "FAT32 Info Sector",
+   "FAT32 Backup Boot",
+
    0
 };
    int i;
+   long numclust = 0xFFFF;
+   int fatbits = 0;
+   int fat_len = -1;
 
    for(i=0; dosflds[i].offset >= 0; i++)
    {
-      printf("%-35s", fieldnames[i]);
+      if( i>= DOS4_MAXSECT && (fat_len==0) != (i>=DOS7_MAXSECT) )
+	 continue;
+
       if( dosflds[i].length <= 4 )
       {
          long v = 0; int j;
@@ -620,11 +810,23 @@ static char * fieldnames[] = {
 	 {
 	    v = v*256 + (0xFF&( bootsect[dosflds[i].offset+j] ));
 	 }
-	 printf("%ld\n", v);
+
+	 if( i==DOS_FATLEN )
+	    fat_len = v;
+
+	 if (v==0 && 
+	  (i==DOS_FATLEN || i==DOS_MAXSECT || i==DOS4_MAXSECT || i==DOS_NROOT))
+	    continue;
+
+         printf("%-35s%ld\n", fieldnames[i], v);
+
+	 if (i==DOS_SECT && v!=512 && v!=1024 && v!=2048)
+	    break;
       }
       else
       {
          int ch, j;
+         printf("%-35s", fieldnames[i]);
 	 for(j=0; j<dosflds[i].length; j++)
 	 {
 	    ch = bootsect[dosflds[i].offset+j];
@@ -643,6 +845,13 @@ char * bootsect;
 
    for(i=0; dosflds[i].offset >= 0; i++)
    {
+      if( i>= DOS4_MAXSECT && 
+	    (dosflds[DOS_FATLEN].value==0) != (i>=DOS7_MAXSECT) )
+      {
+	 dosflds[i].lvalue = dosflds[i].value = 0;
+	 continue;
+      }
+
       if( dosflds[i].length <= 4 )
       {
          long v = 0; int j;
@@ -654,7 +863,7 @@ char * bootsect;
 	 dosflds[i].lvalue = v;
       }
       else
-	 dosflds[i].value = 0;
+	 dosflds[i].lvalue = dosflds[i].value = 0;
    }
 }
 
@@ -680,7 +889,10 @@ check_msdos()
       dosflds[DOS_CLUST].value = 1;
 
    if( dosflds[DOS_MEDIA].value < 0xF0 )
-      fprintf(stderr, "Dos media descriptor is invalid\n");
+   {
+      if (!force)
+         fprintf(stderr, "Dos media descriptor is invalid\n");
+   }
    else if( dosflds[DOS_MEDIA].value != (0xFF&buffer[512])
          && dosflds[DOS_RESV].value == 1 )
       fprintf(stderr, "Dos media descriptor check failed\n");
@@ -728,7 +940,7 @@ check_msdos()
 check_simpledos(bb_fatbits)
 int bb_fatbits;
 {
-   unsigned numclust = 0xFFFF;
+   long numclust = 0xFFFF;
    char * err = 0;
    int fatbits = 0;
 
@@ -739,19 +951,24 @@ int bb_fatbits;
                    - dosflds[DOS_NFAT].value * dosflds[DOS_FATLEN].value
                    - ((dosflds[DOS_NROOT].value+15)/16)
                  ) / dosflds[DOS_CLUST].value + 2;
-   else
+   else if( dosflds[DOS4_MAXSECT].value > 0 )
       numclust = ( dosflds[DOS4_MAXSECT].lvalue
                    - dosflds[DOS_RESV].value
                    - dosflds[DOS_NFAT].value * dosflds[DOS_FATLEN].value
                    - ((dosflds[DOS_NROOT].value+15)/16)
                  ) / dosflds[DOS_CLUST].value + 2;
+   else
+      numclust = ( dosflds[DOS7_MAXSECT].lvalue
+                   - dosflds[DOS_RESV].value
+                   - dosflds[DOS_NFAT].value * dosflds[DOS7_FAT32LEN].value
+                 ) / dosflds[DOS_CLUST].value;
 
    if( memcmp(buffer+dosflds[DOS4_FATTYPE].offset, "FAT12", 5) == 0 )
       fatbits=12;
    else if( memcmp(buffer+dosflds[DOS4_FATTYPE].offset, "FAT16", 5) == 0 )
       fatbits=16;
    else
-      fatbits=12+4*(numclust > 0xFF0);
+      fatbits=12+4*(numclust > 0xFF0) + 16*(numclust > 0xFFF0L);
 
    if( dosflds[DOS_NFAT].value > 2 )
       err = "Too many fat copies on disk";
@@ -759,15 +976,19 @@ int bb_fatbits;
       err = "Root directory has unreasonable size.";
    else if( dosflds[DOS_SECT].value != 512 )
       err = "Drive sector size isn't 512 bytes sorry no-go.";
+   else if( fatbits == 16 && numclust < 0xFF0 )
+      err = "Weirdness, FAT16 but less than $FF0 clusters";
    else if( fatbits != bb_fatbits )
       err = "Filesystem has the wrong fat type for this bootblock.";
    else if( numclust * dosflds[DOS_CLUST].lvalue / 
 	    dosflds[DOS_SPT].value > 65535 )
-      err = "Maximum of 65535 tracks allowed, sorry";
+      err = "Boot sector untested with more than 65535 tracks";
 
    if( !err && bb_fatbits == 12 )
    {
-      if( (0x7C00-msdos_start-512)/512 < dosflds[DOS_FATLEN].value )
+      if( dosflds[DOS4_PHY_DRIVE].value != 0 )
+         err = "This boot sector is only for floppies";
+      else if( (0x7C00-msdos_start-512)/512 < dosflds[DOS_FATLEN].value )
          err = "The FAT is too large to load in the available space.";
       else if( dosflds[DOS_RESV].value + dosflds[DOS_FATLEN].value > 
                dosflds[DOS_SPT].value )
@@ -819,7 +1040,7 @@ int boot_name;
 
    if( strlen(boot_id) > i )
    {
-      fprintf(stderr, "Filename '%s' is too long for bootblock\n");
+      fprintf(stderr, "Name '%s' is too long for bootblock\n");
       exit(1);
    }
    else
@@ -840,6 +1061,10 @@ int boot_name;
 	       default:  buffer[j++] = boot_id[i]; break;
 	    }
 	 }
+#ifdef __MSDOS__
+	 else if(boot_id[i] == '_')   buffer[j++] = ' ';
+	 else if(boot_id[i] == '^') { buffer[j++] = '\r'; buffer[j++] = '\n'; }
+#endif
 	 else buffer[j++] = boot_id[i];
       }
       buffer[j] = 0;
@@ -857,28 +1082,37 @@ check_mbr()
       if( buffer[i] )
          break;
 
+   /* Check for Disk Manager partition tables */
+   if( buffer[252] == 0xAA && buffer[253] == 0x55 )
+   {
+      if( (unsigned char)mbr_data[252] != 0xAA || mbr_data[253] != 0x55 )
+	 i = 252;
+   }
+
    if( i != 512 )
    {
       if(force)
-         fprintf(stderr, "That doesn't look like an MBR zapping\n");
+         fprintf(stderr, "That doesn't look like a compatible MBR but ...\n");
       else
       {
-         fprintf(stderr, "That doesn't look like an MBR, -f will zap\n");
+         fprintf(stderr, "That doesn't look like a compatible MBR\n");
          exit(1);
       }
-
-      memset(buffer, '\0', 512);
    }
 }
 
 copy_mbr(mbr_data)
 char * mbr_data;
 {
-   if( buffer[252] != 0xAA || buffer[253] != 0x55 )
+   if( buffer[252] != 0xAA || buffer[253] != 0x55 ||
+       (unsigned char)mbr_data[252] != 0xAA || mbr_data[253] != 0x55 )
       memcpy(buffer, mbr_data, 446);
    else
       memcpy(buffer, mbr_data, 254);
-   memcpy(buffer+510, mbr_data+510, 2);
+
+   buffer[510] = 0x55;
+   buffer[511] = 0xAA;
+   write_zero = 1;
 }
 
 /**************************************************************************/
@@ -1142,7 +1376,7 @@ do_2m_write()
 #ifdef HAS_2M20
    else if( disk_trck != 82 || disk_sect != 22 )
    {
-      fprintf(stderr, "To be bootable a 2M disk must be 22 sectors 82 tracks or formatted with 2m20.\n");
+      fprintf(stderr, "To be bootable a 2M disk must be 22 sectors 82 tracks or formatted with DOS 2m.\n");
       if( !force ) exit(1);
       fprintf(stderr, "But I'll try it\n");
    }
@@ -1166,7 +1400,7 @@ do_2m_write()
       write_sector(bs_offset+i/512+1, program_2m_vsn_20+i);
    }
 #else
-   fprintf(stderr, "To be bootable a 2M disk must be formatted with the 2m20 device driver.\n");
+   fprintf(stderr, "To be bootable a 2M disk must be formatted with the DOS 2m driver.\n");
    exit(1);
 #endif
 }
diff --git a/bootblocks/mbr.s b/bootblocks/mbr.s
index 3a22984..113bb51 100644
--- a/bootblocks/mbr.s
+++ b/bootblocks/mbr.s
@@ -3,37 +3,38 @@
 ! This BB successfully boots MSDOS or Linux.
 !
 ! In addition it has the facility to load and execute a small program
-! (of 8 extents) before the boot blocks are checked.
+! before the boot blocks are checked.
 !
 ! Or
 !
-! Space for 12 extra partitions in a form that Linux _does_ understand.
+! Space for 12 extra partitions in the 'DiskManager' form that Linux 
+! _does_ understand.
 !
+! NB: This needs Dev86 0.15.2 or later
 
 ! Lowest available is $0500, MSDOS appears to use $0600 ... I wonder why?
 ORGADDR=$0500
 preboot=0	! Include the pre-boot loader.
-diskman=1	! Disk manager partitions, allows 16 partitions but
+mbrkey=0	! Option to choose the boot record base on keystroke
+message=0	! Display boot message
+diskman=0	! Disk manager partitions, allows 16 partitions but
 		! don't overwrite this with a LILO BB.
 
-! Include standard layout
-org ORGADDR
-include sysboot.s
-
-public partition_1
-public partition_2
-public partition_3
-public partition_4
+linear=0	! Use the linear addresses not the CHS ones
 
- if diskman=0
-org ORGADDR+$3
-.ascii "ELKS MBR     Copyright 1996, Robert de Bath"
+partition_start=ORGADDR+0x1BE
+partition_size=0x10
+partition_end=ORGADDR+0x1FE
 
-! Start after dos fsstat data, not strictly required.
-org codestart
+ if diskman
+  ! Partition table start ...
+  table_start=ORGADDR+0xFC
+  low_partition=table_start+2
  else
-org ORGADDR
+  table_start=partition_start
  endif
+
+org ORGADDR
   cli			! Assume _nothing_!
   cld
   mov	bx,#$7C00	! Pointer to start of BB.
@@ -51,52 +52,38 @@ org ORGADDR
 cont:
   sti			! Let the interrupts back in.
 
-!
-! Next check for a pre-boot load.
-
+! Next check for a pre-boot load or a keypress
+ if message
+  call disp_message
+ endif
  if preboot
-  push	bx
-  mov	si,#pre_boot_table
-  lodsw
-  mov	di,ax		! First word is execute address
-more_boot:
-  lodsw
-  test	ax,ax
-  jz	load_done
-  mov	bx,ax		! word 1 address
-  lodsw
-  mov	cx,ax		! word 2 CX, head/sector
-  lodsw
-  mov	dx,ax		! word 3 DX, drive, cylinder
-  lodsw			! word 4 AX, $02, sector count
-  int	$13
-  jnc	more_boot	! This doesn't retry, with a HD it shouldn't be bad.
-  jc	disk_error
-load_done:
-  call	di
-exec_done:
-  pop	bx
+  call preboot_code
+ endif
+ if mbrkey
+  call 	key_wait
  endif
 
 ! Now check the partition table, must use SI as pointer cause that's what the
 ! partition boot blocks expect.
 
-  mov	si,#partition_1
+  mov	si,#partition_start
 check_active:
   cmp	byte [si],#$80			! Flag for activated partition
   jz	found_active
+ if mbrkey=0
 bad_boot:
-  add	si,#partition_2-partition_1
-  cmp	si,#bootblock_magic
+ endif
+  add	si,#partition_size
+  cmp	si,#partition_end
   jnz	check_active
 
-  ! Check for Disk manager partitions (12 more!)
+  ! Check for Disk manager partitions in the order that Linux numbers them.
  if diskman
   cmp	word ptr diskman_magic,#$55AA
   jnz	no_diskman
-  mov	si,#partition_1
+  mov	si,#partition_start
 check_next:
-  sub	si,#partition_2-partition_1
+  sub	si,#partition_size
   cmp	byte [si],#$80			! Flag for activated partition
   jz	found_active
   cmp	si,#low_partition
@@ -109,10 +96,14 @@ no_diskman:
   jmp	no_boot
 
 found_active:
+ if linear
+  call linearise
+ else
   mov	di,#6		! Max retries, int list says 3 ... double it
   mov	dx,[si]		! dh = Drive head, dl = $80 ie HD drive 0
   mov	cx,[si+2]	! cx = Sector & head encoded for int $13
-  ! bx is correct
+  ! bx is correct at $7C00
+ endif
 retry:
   movb	[$7DFE],#0	! Clear magic for dosemu
   mov	ax,#$0201	! Read 1 sector
@@ -126,9 +117,8 @@ retry:
   dec	di
   jnz	retry		! Try again
 
-disk_error:
   mov	si,#disk_read_error
-  jmp	no_boot			! Sorry it ain't gonna work.
+  jmp	no_boot		! Sorry it ain't gonna work.
 
 sector_loaded:
   mov	di,#$7DFE	! End of sector loaded
@@ -139,6 +129,19 @@ sector_loaded:
   jmpi	#$7C00,#0	! Go!
 
 ! Fatal errors ...........
+ if mbrkey
+bad_boot:
+  mov	si,#no_bootpart
+no_boot:		! SI now has pointer to error message
+  call	puts
+  mov	si,#crlf
+  call	puts
+tick:
+  call	key_wait
+  j	tick
+
+ else
+
 no_boot:		! SI now has pointer to error message
   lodsb
   cmp	al,#0
@@ -156,65 +159,242 @@ EOS:
 keyboot:		! Wait for a key then reboot
   xor	ax,ax
   int	$16
-  int	$19		! This should be OK as we haven't touched anything.
+! int	$19		! This rarely does anything useful...
   jmpi	$0,$FFFF	! Wam! Try or die!
 
-no_bootpart:
-  .asciz	"No bootable partition"
-disk_read_error:
-  .asciz	"Error loading system"
 press_key:
-  .asciz	"\r\nPress a key to reboot"
+  .asciz	"\r\nPress return:"
 press_end:
+ endif
+
+no_bootpart:
+  .asciz	"No active partition"
+disk_read_error:
+  .asciz	"Disk read error"
+
+!-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+! Instead of loading using the CHS data in the ptbl use the linear addr
+!
+ if linear
+linearise:
+  mov	di,#6		! Max retries, int list says 3 ... double it
+  mov	dx,[si]		! dh = Drive head, dl = $80 ie HD drive 0
+  mov	cx,[si+2]	! cx = Sector & head encoded for int $13
+  ! bx is correct at $7C00
+
+  fail! Todo ...
+  ret
+ endif
+
+!-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+! Choose the partition based on a pressed key ...
+
+ if mbrkey
+key_wait:
+  mov	si,#Prompt
+  call	puts
+  mov	di,#19			! Wait for 18-19 ticks
+
+next_loop:
+  mov	ah,#1
+  int	$16
+  jnz   Got_key
+  mov	ah,#0
+  int	$1A			! Get current tick
+  cmp	dx,si			! If changed DEC our counter.
+  jz	next_loop
+  mov	si,dx
+  dec	di
+  jnz	next_loop
+
+  mov	si,#Unprompt		! Nothing has happened, return.
+  call	puts
+
+bad_key:
+  ret
+
+Got_key:
+  cmp	al,#$20
+  jnz	not_space
+  mov	si,#Pause
+  j	showit
+not_space:
+  mov	Showkey,al
+  mov	si,#Showkey
+showit:
+  call	puts
+
+  mov	ah,#0			! Clean the kbd buffer.
+  int	$16
+
+  ! ... Now we use our key ...
+  ! 0 		=> Floppy
+  ! 1 .. 4	=> Hard disk partition.
+
+  mov	di,#-1
+  cmp	al,#$20
+  jz	next_loop
 
+  and	ax,#0xF
+
+  jnz	not_floppy
+  mov	si,#floppy_part
+  br	found_active
+
+not_floppy:
+  dec	ax
+  test	ax,#0xC
+  jnz	bad_key
+
+  mov	cl,#4
+  shl	ax,cl
+  add	ax,#partition_start
+  mov	si,ax
+
+! Set active flag for disk interrupt.
+  or	byte [si],#$80
+
+  br	found_active
+
+puts:
+  lodsb
+  cmp	al,#0
+  jz	EOS
+  push	bx
+  mov	bx,#7
+  mov	ah,#$E			! Can't use $13 cause that's AT+ only!
+  int	$10
+  pop	bx
+  jmp	puts
+EOS:
+  ret
+
+Prompt:
+  .asciz	"MBR: "
+Unprompt:
+  .asciz	"\b\b\b\b\b     \b\b\b\b\b"
+Pause:
+  .asciz	"\b\b> "
+Showkey:
+  .ascii	" "
+crlf:
+  .asciz	"\r\n"
+floppy_part:
+  .word	0,1
+
+ endif
+
+!-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+!
+ if message
+disp_message:
+  mov	si,#Banner
+
+ if mbrkey
+  br	puts
+ else
+
+puts:
+  lodsb
+  cmp	al,#0
+  jz	.EOS
+  push	bx
+  mov	bx,#7
+  mov	ah,#$E			! Can't use $13 cause that's AT+ only!
+  int	$10
+  pop	bx
+  jmp	puts
+.EOS:
+  ret
+ endif
+export Banner
+Banner:
+  .asciz	""
+ endif
+!-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+! This is the pre-boot loader it uses CHS but that's ok for track 0
+!
  if preboot
+public preboot_code
+preboot_code:
+  push	bx
+  mov	si,#pre_boot_table
+  lodsw
+  mov	di,ax		! First word is execute address
+more_boot:
+  lodsw
+  test	ah,ah
+  jz	load_done
+  mov	bx,ax		! word 1 address
+  lodsw
+  mov	cx,ax		! word 2 CX, head/sector
+  lodsw
+  mov	dx,ax		! word 3 DX, drive, cylinder
+  lodsw			! word 4 AX, $02, sector count
+  int	$13
+  jnc	more_boot	! This doesn't retry, with a HD it shouldn't be bad.
+
+  mov	si,#disk_read_error
+  br	no_boot		! Sorry it ain't gonna work.
+load_done:
+  call	di
+exec_done:
+  pop	bx
+
 return:
   ret
 
 export pre_boot_table
 pre_boot_table:
+  ! Example: Do nothing.
+  .word return,0
+
+  ! Labels
+  ! .word <execute address>
+  ! Then repeat ..
+  ! .word <BX>, <CX>, <DX>, <AX>
+  ! Finally
+  ! .word 0
+
   ! Example: Load rest of H0,C0 into mem at $7C00 (8k).
-  ! .word $7C00, $7C00,$0002,$0000,$0210, $0000
-  .word return
-  .word	0
+  ! .word $7C00, $7C00,$0002,$8000,$0210, $0000
+
+  ! Example: Use single LBA call
+  ! .word <execute address>
+  ! .word 0,0,$8000,$4200, $0010
+  ! .word <number of blocks>
+  ! .long <transfer buffer>
+  ! .long <start block number>
+  ! .long <start block number high 4 bytes>
  endif
 
- if diskman
+!-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+! Now make sure this isn't too big!
+  if *>table_start
+   fail! Partition table overlaps
+  endif
 
+!-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+! The diskman magic number and empty DM partitions.
+ if diskman
   org ORGADDR+0xFC
 public diskman_magic
 diskman_magic:
   .word 0xAA55
-low_partition:
-public partition_16
-partition_16 = low_partition+0x00
-public partition_15
-partition_15 = low_partition+0x10
-public partition_14
-partition_14 = low_partition+0x20
-public partition_13
-partition_13 = low_partition+0x30
-public partition_12
-partition_12 = low_partition+0x40
-public partition_11
-partition_11 = low_partition+0x50
-public partition_10
-partition_10 = low_partition+0x60
-public partition_9
-partition_9 = low_partition+0x70
-public partition_8
-partition_8 = low_partition+0x80
-public partition_7
-partition_7 = low_partition+0x90
-public partition_6
-partition_6 = low_partition+0xA0
-public partition_5
-partition_5 = low_partition+0xB0
+  .blkb 12*partition_size-1
+  .byte 0
+ endif
+
+!-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+! And finally a copyright message if there's room.
+ if *<ORGADDR+0x180
+  org ORGADDR+0x180
+.asciz "ELKS MBR       "
+.asciz "Robert de Bath,"
+.asciz "Copyright  1996-2000."
+  org partition_start-1
+  .byte 0xFF
  endif
 
-! Now make sure this isn't to big!
-  if *>partition_1
-   fail! Partition overlap
-  endif
 
 !THE END
diff --git a/bootblocks/msdos.s b/bootblocks/msdos.s
index f291b6b..b9f02a9 100644
--- a/bootblocks/msdos.s
+++ b/bootblocks/msdos.s
@@ -19,10 +19,9 @@
 !
 ! All these are true for mtools created floppies on normal PC drives.
 !
-! In addition this now has a compile time option for 16 bit FAT floppies
-! TODO: Hard partition (dos_hidden != 0)
-!       Zip disks (floppy with dos_hidden != 0)
-!       Auto detect disk type
+! In addition this now has a compile time option for FAT16 partitions.
+! TODO: Auto detect disk type
+!       FAT32
 !
 !---------------------------------------------------------------------------
 ORGADDR=$0500
@@ -37,6 +36,13 @@ fatbits=12		! Set to 12 or 16 (16 for LS-120 disks)
 export heads
 heads=0			! This can be 0,1 or 2. 0 is dynamic.
 
+export harddisk
+ if fatbits=12
+harddisk=0
+ else
+harddisk=1		! Allow for hard disks, but will only work with 
+ endif			! disks formatted >= MSDOS 4.0
+
 !---------------------------------------------------------------------------
 ! Absolute position macro, fails if code before it is too big.
 macro locn
@@ -185,6 +191,9 @@ linsect2:
   and   al,#$C0
   or    cl,al
  endif
+ if harddisk
+  mov	dl,[dos4_phy_drive]
+ endif
   ret
 
 !---------------------------------------------------------------------------
@@ -332,13 +341,18 @@ got_fsect:
 !---------------------------------------------------------------------------
 ! File is now loaded, execute it.
 maincode:
+ if harddisk=0
   mov	bx,#7
   mov	ax,#$0E3E
   int	$10		! Marker printed to say bootblock succeeded.
+ endif
 
   xor	dx,dx		! DX=0 => floppy drive
+ if harddisk
+  mov	dl,[dos4_phy_drive]
+ endif
   push	dx		! CX=0 => partition offset = 0
-  mov	si,[dos_spt]	! SI=Sectors pet track
+  mov	si,[dos_spt]	! SI=Sectors per track
 
   mov	bx,#LOADSEG
   mov	ds,bx		! DS = loadaddress
@@ -390,12 +404,9 @@ boot_name:
 name_end:
 !        NNNNNNNNEEE
 
-if fatbits =16
 locn(510)
-  .word 0	! This is a floppy so it should not need the magic _but_
+  .word $AA55	! This is a floppy so it should not need the magic _but_
   		! the debian MBR requires the magic even on floppies
-		! so only clear on a superfloppy (LS-120).
-endif
 
 fat_table:	! This is the location that the fat table is loaded.
 		! Note: The fat must be entirely on track zero if 12 bit.
diff --git a/bootblocks/sysboot.s b/bootblocks/sysboot.s
index 558d02e..baac806 100644
--- a/bootblocks/sysboot.s
+++ b/bootblocks/sysboot.s
@@ -35,12 +35,13 @@ dos_heads:	.blkw 1		! Heads
 dos_hidden:	.blkw 2		! Hidden sectors
 
 ! Here down is DOS 4+ and probably not needed for floppy boots.
-floppy_temp:
 
 dos4_maxsect:	.blkw 2		! Large FS sector count
 dos4_phy_drive:	.blkb 1		! Phys drive
 .blkb 1		! Reserved
 .blkb 1		! DOS 4
+
+floppy_temp:
 dos4_serial:	.blkw 2		! Serial number
 dos4_label:	.blkb 11	! Disk Label (DOS 4+)
 dos4_fattype:	.blkb 8		! FAT type