diff --git a/libisoburn/trunk/xorriso/xorriso.1 b/libisoburn/trunk/xorriso/xorriso.1
index e9d05073..21079486 100644
--- a/libisoburn/trunk/xorriso/xorriso.1
+++ b/libisoburn/trunk/xorriso/xorriso.1
@@ -2532,6 +2532,10 @@ correction will fail and the drive is supposed to indicate error.
 xorriso can scan the media for readable data blocks, classify them according
 to their read speed, save them to a file, and keep track of successfuly saved
 blocks for further tries on the same media.
+.br
+By option -md5 checksums may get recorded with data files and whole
+sessions. These checksums are reachable only via indev and a loaded image.
+They work independently of the media type and can detect transmission errors.
 .TP
 \fB\-check_media\fR [option [option ...]] --
 Try to read data blocks from the indev drive, eventually copy them to a
@@ -2642,6 +2646,10 @@ of the program run. Severity ALL suppresses that event.
 This option reports match and mismatch of data files to the result channel.
 Non-data files cause NOTE events. There will also be UPDATE events from
 data reading.
+.br
+If no iso_rr_path is given then the whole loaded session is compared with its
+MD5 sum. Be aware that this covers only one session and not the whole image
+if there are older sessions.
 .TP
 \fB\-check_md5_r\fR severity iso_rr_path [***]
 Like -check_md5 but checking all data files underneath the given paths.
diff --git a/libisoburn/trunk/xorriso/xorriso.c b/libisoburn/trunk/xorriso/xorriso.c
index 391fe396..391b900b 100644
--- a/libisoburn/trunk/xorriso/xorriso.c
+++ b/libisoburn/trunk/xorriso/xorriso.c
@@ -8357,8 +8357,9 @@ int Xorriso_opt_args(struct XorrisO *xorriso, char *cmd,
    *optc= 0;
    *optv= NULL;
    sprintf(xorriso->info_text, "%s : Not enough arguments given", cmd);
-   if(!(flag & 128))
-     Xorriso_msgs_submit(xorriso, 0, xorriso->info_text, 0, "SORRY", 0);
+   if((flag & 128))
+     return(1);
+   Xorriso_msgs_submit(xorriso, 0, xorriso->info_text, 0, "SORRY", 0);
    return(0);
  }
  *end_idx= Xorriso_end_idx(xorriso, argc, argv, idx,
@@ -12470,8 +12471,8 @@ ex:;
 }
 
 
-int Xorriso_report_m5_outcome(struct XorrisO *xorriso, char *severity,
-                              int flag)
+int Xorriso_report_md5_outcome(struct XorrisO *xorriso, char *severity,
+                               int flag)
 {
  if((xorriso->find_check_md5_result & 3) == 0) {
    sprintf(xorriso->result_line,
@@ -13367,21 +13368,20 @@ int Xorriso_option_check_md5(struct XorrisO *xorriso,
    Xorriso_msgs_submit(xorriso, 0, xorriso->info_text, 0, "FAILURE", 0);
    return(ret);
  }
+ (*idx)++;
 
- ret= Xorriso_opt_args(xorriso, "-check_md5", argc, argv, (*idx) + 1, 
+ ret= Xorriso_opt_args(xorriso, "-check_md5", argc, argv, *idx, 
                        &end_idx, &optc, &optv, 128);
  if(ret<=0)
    goto ex;
 
+ xorriso->find_check_md5_result= 0;
+
  if(optc == 0) {
-
-   /* >>> check whole session */;
-   ret= 1;
-
-   return(ret);
+   ret= Xorriso_check_session_md5(xorriso, severity, 0);
+   goto ex;
  } 
 
- xorriso->find_check_md5_result= 0;
  for(i= 0; i < optc; i++) {
    if(flag & 8) {
      ret= Findjob_new(&job, optv[i], 0);
@@ -13422,7 +13422,7 @@ int Xorriso_option_check_md5(struct XorrisO *xorriso,
    Xorriso_pacifier_callback(xorriso, "content bytes read",
                              xorriso->pacifier_count, 0, "", 1);
 report_outcome:;
- Xorriso_report_m5_outcome(xorriso, severity, 0);
+ Xorriso_report_md5_outcome(xorriso, severity, 0);
 
 ex:;
  (*idx)= end_idx;
diff --git a/libisoburn/trunk/xorriso/xorriso_private.h b/libisoburn/trunk/xorriso/xorriso_private.h
index 513c4230..ac258219 100644
--- a/libisoburn/trunk/xorriso/xorriso_private.h
+++ b/libisoburn/trunk/xorriso/xorriso_private.h
@@ -675,8 +675,8 @@ int Xorriso_compare_2_files(struct XorrisO *xorriso, char *disk_adr,
                             char *iso_adr, char *adr_common_tail,
                             int *result, int flag);
 
-int Xorriso_report_m5_outcome(struct XorrisO *xorriso, char *severity, 
-                              int flag);
+int Xorriso_report_md5_outcome(struct XorrisO *xorriso, char *severity, 
+                               int flag);
 
 
 int Sfile_str(char target[SfileadrL], char *source, int flag);
diff --git a/libisoburn/trunk/xorriso/xorriso_timestamp.h b/libisoburn/trunk/xorriso/xorriso_timestamp.h
index c42f3c99..ed36cd0b 100644
--- a/libisoburn/trunk/xorriso/xorriso_timestamp.h
+++ b/libisoburn/trunk/xorriso/xorriso_timestamp.h
@@ -1 +1 @@
-#define Xorriso_timestamP "2009.08.12.130401"
+#define Xorriso_timestamP "2009.08.12.202423"
diff --git a/libisoburn/trunk/xorriso/xorrisoburn.c b/libisoburn/trunk/xorriso/xorrisoburn.c
index 20acd387..8be7cf23 100644
--- a/libisoburn/trunk/xorriso/xorrisoburn.c
+++ b/libisoburn/trunk/xorriso/xorrisoburn.c
@@ -8283,7 +8283,7 @@ int Xorriso_findi_sorted(struct XorrisO *xorriso, struct FindjoB *job,
  ret= 1;
 ex:;
  if((flag & 8) && job->action == 35)
-   Xorriso_report_m5_outcome(xorriso, job->target, 0);
+   Xorriso_report_md5_outcome(xorriso, job->target, 0);
  if(!(flag & (2 | 4)))
    Xorriso_destroy_node_array(xorriso, 0);
  if(hmboss != NULL)
@@ -12208,3 +12208,97 @@ ex:;
    iso_md5_end(&ctx, data_md5);
  return(ret);
 }
+
+
+int Xorriso_check_md5_range(struct XorrisO *xorriso, off_t start_lba,
+                            off_t end_lba, char md5[16], int flag)
+{
+ int ret, i;
+ struct burn_drive_info *dinfo= NULL;
+ struct burn_drive *drive= NULL;
+ off_t pos, data_count, to_read;
+ char data[64 * 1024], data_md5[16];
+ void *ctx = NULL;
+
+ ret= Xorriso_get_drive_handles(xorriso, &dinfo, &drive,
+                                "on attempt to check session MD5 checksum", 0);
+ if(ret <= 0)
+   goto ex;
+ ret= iso_md5_start(&ctx);
+ if(ret <= 0) {
+   Xorriso_no_malloc_memory(xorriso, NULL, 0);
+   goto ex;
+ }
+ for(pos= start_lba; pos < end_lba; pos+= 32) {
+   to_read= 32;
+   if(pos + to_read > end_lba)
+     to_read= end_lba - pos; 
+   ret= burn_read_data(drive, pos * (off_t) 2048, data,
+                       to_read * (off_t) 2048, &data_count, 0);
+   if(ret <= 0)
+     goto ex;
+   iso_md5_compute(ctx, data, (int) data_count);
+   xorriso->pacifier_count+= data_count; 
+   xorriso->pacifier_byte_count+= data_count;
+   Xorriso_pacifier_callback(xorriso, "content bytes read",
+                             xorriso->pacifier_count, 0, "", 0);
+ }
+ iso_md5_end(&ctx, data_md5);
+ for(i= 0; i < 16; i++)
+   if(md5[i] != data_md5[i])
+ break;
+ ret= 1;
+ if(i < 16 )
+   ret= 0;
+ex:;
+ Xorriso_process_msg_queues(xorriso,0);
+ if(ctx != NULL)
+   iso_md5_end(&ctx, data_md5);
+ return(ret);
+}
+
+
+int Xorriso_check_session_md5(struct XorrisO *xorriso, char *severity,
+                              int flag)
+{
+ int ret, i;
+ IsoImage *image;
+ uint32_t start_lba, end_lba;
+ char md5[16], md5_text[33];
+
+ ret= Xorriso_get_volume(xorriso, &image, 0);
+ if(ret<=0)
+   return(ret);
+ ret= iso_image_get_session_md5(image, &start_lba, &end_lba, md5, 0);
+ Xorriso_process_msg_queues(xorriso,0);
+ if(ret < 0)
+   return(ret);
+ if(ret == 0) {
+   sprintf(xorriso->info_text,
+           "No session MD5 is recorded with the loaded session");
+   Xorriso_msgs_submit(xorriso, 0, xorriso->info_text, 0, "WARNING", 0);
+   return(0);
+ }
+ for(i= 0; i < 16; i++)
+   sprintf(md5_text + 2 * i, "%2.2x", ((unsigned char *) md5)[i]);
+ sprintf(xorriso->info_text,
+         "Session MD5 %s , LBA %.f , %.f blocks\n",
+         md5_text, (double) start_lba, (double) end_lba - start_lba);
+ Xorriso_info(xorriso, 0);
+ ret= Xorriso_check_md5_range(xorriso, (off_t) start_lba, (off_t) end_lba,
+                              md5, 0);
+ if(ret <= 0) {
+   sprintf(xorriso->result_line, "MD5 MISMATCH WITH DATA OF LOADED SESSION\n");
+   Xorriso_result(xorriso,0);
+   if(strcmp(severity, "ALL") != 0) {
+     sprintf(xorriso->info_text, "Event triggered by MD5 comparison mismatch");
+     Xorriso_msgs_submit(xorriso, 0, xorriso->info_text, 0, severity, 0);
+   }
+ } else {
+   sprintf(xorriso->result_line, "md5 of session data matches recorded md5\n");
+   Xorriso_result(xorriso,0);
+ }
+ return(ret);
+}
+ 
+
diff --git a/libisoburn/trunk/xorriso/xorrisoburn.h b/libisoburn/trunk/xorriso/xorrisoburn.h
index 558fa232..0e1bb10b 100644
--- a/libisoburn/trunk/xorriso/xorrisoburn.h
+++ b/libisoburn/trunk/xorriso/xorrisoburn.h
@@ -324,6 +324,9 @@ int Xorriso_restore_node_array(struct XorrisO *xorriso, int flag);
 int Xorriso_check_md5(struct XorrisO *xorriso, void *in_node, char *path,
                       int flag);
 
+int Xorriso_check_session_md5(struct XorrisO *xorriso, char *severity,
+                              int flag);
+
 
 struct CheckmediajoB {
  int use_dev;        /* 0= use indev , 1= use outdev , 2= use sector map*/