- The maximum number of heads is 255, not 256.

Pointed out by:		marcel

lib/libdisk/change.c

@@ -36,7 +36,7 @@ Sanitize_Bios_Geom(struct disk *disk)
 
 	if (disk->bios_cyl >= 65536)
 		sane = 0;
-	if (disk->bios_hd > 256)
+	if (disk->bios_hd >= 256)
 		sane = 0;
 #ifdef PC98
 	if (disk->bios_sect >= 256)

sbin/fdisk/fdisk.c

@@ -1066,8 +1066,8 @@ process_geometry(CMD *command)
 	    warnx("ERROR line %d: number of heads not specified",
 		    current_line_number);
 	    status = 0;
-	    } else if (dos_heads > 256) {
-	    warnx("ERROR line %d: number of heads must be within (1-256)",
+	    } else if (dos_heads > 255) {
+	    warnx("ERROR line %d: number of heads must be within (1-255)",
 		    current_line_number);
 	    status = 0;
 	}