diff --git a/xorriso/xorriso.1 b/xorriso/xorriso.1
index 63d68221..c8173061 100644
--- a/xorriso/xorriso.1
+++ b/xorriso/xorriso.1
@@ -2,7 +2,7 @@
 .\" First parameter, NAME, should be all caps
 .\" Second parameter, SECTION, should be 1-8, maybe w/ subsection
 .\" other parameters are allowed: see man(7), man(1)
-.TH XORRISO 1 "Oct 27, 2009"
+.TH XORRISO 1 "Nov 17, 2009"
 .\" Please adjust this date whenever revising the manpage.
 .\"
 .\" Some roff macros, for reference:
@@ -1992,6 +1992,19 @@ in order to set an own address limit.
 "data" causes full speed to start when superblock and directory entries are
 written and writing of file content blocks begins.
 .TP
+\fB-dvd_obs\fR "default"|"32k"|"64k"
+Linux specific:
+Set the number of bytes to be transmitted with each write operation to DVD
+or BD media. A number of 64 KB may improve throughput with bus systems which
+show latency problems. The default depends on media type, on option
+-stream_recording , and on compile time options.
+.TP
+\fB-stdio_sync\fR "on"|"off"|number
+Set the number of bytes after which to force output to stdio: pseudo drives.
+This forcing keeps the memory from being clogged with lots of
+pending data for slow devices. Default "on" is the same as "16m".
+Forced output can be disabled by "off".
+.TP
 \fB\-dummy\fR "on"|"off"
 If "on" then simulate burning or refuse with FAILURE event if
 no simulation is possible, do neither blank nor format.
@@ -2934,10 +2947,12 @@ Writing to stdout is possible only if -as "mkisofs" was among the start
 arguments or if other start arguments pointed the output drive to
 standard output.
 .br
-Not original mkisofs options are --quoted_path_list (see -quoted_path_list),
-isolinux_mbr= (see -boot_image isolinux isohybrid=),
---hardlinks (see -hardlinks "on") --acl (see -acl "on"),
---xattr (see -xattr "on").
+Not original mkisofs options are --quoted_path_list , --hardlinks , --acl ,
+--xattr , --md5 , --stdio_sync . They work like the xorriso options with the
+same name and hardcoded argument "on", e.g. -acl "on".
+Explicit arguments are expected by --stdio_sync and --scdbackup_tag.
+.br
+Quite special is isolinux_mbr= (see -boot_image isolinux isohybrid=).
 .br
 Personalites "\fBxorrisofs\fR", "\fBgenisoimage\fR", and "\fBgenisofs\fR"
 are aliases for "mkisofs".
diff --git a/xorriso/xorriso.c b/xorriso/xorriso.c
index 4d007fa4..3f8c316a 100644
--- a/xorriso/xorriso.c
+++ b/xorriso/xorriso.c
@@ -4819,6 +4819,8 @@ int Xorriso_new(struct XorrisO ** xorriso,char *progname, int flag)
  m->padding= 300*1024;
  m->alignment= 0;
  m->do_stream_recording= 0;
+ m->dvd_obs= 0;
+ m->stdio_sync= 0;
  m->keep_boot_image= 0;
  m->patch_isolinux_image= 0;
  m->boot_image_bin_path[0]= 0;
@@ -7075,6 +7077,31 @@ int Xorriso_status(struct XorrisO *xorriso, char *filter, FILE *fp, int flag)
  if(!(is_default && no_defaults))
    Xorriso_status_result(xorriso,filter,fp,flag&2);
 
+ is_default= (xorriso->dvd_obs == 0);
+ strcpy(mode, "default");
+ if(xorriso->dvd_obs == 32768 || xorriso->dvd_obs == 65536)
+   sprintf(mode, "%dk", xorriso->dvd_obs / 1024);
+ sprintf(line,"-dvd_obs %s\n", mode);
+ if(!(is_default && no_defaults))
+   Xorriso_status_result(xorriso,filter,fp,flag&2);
+
+ is_default= (xorriso->stdio_sync == 0);
+ strcpy(line, "-stdio_sync ");
+ if(xorriso->stdio_sync == -1)
+   strcat(line, "off");
+ else if(xorriso->stdio_sync == 0)
+   strcat(line, "on");
+ else if(xorriso->stdio_sync % 512) {
+   Sfile_off_t_text(line+strlen(line), (off_t) (xorriso->stdio_sync * 2048),
+                    0);
+ } else {
+   Sfile_off_t_text(line+strlen(line), (off_t) (xorriso->stdio_sync / 512), 0);
+   strcat(line, "m"); 
+ }
+ strcat(line, "\n"); 
+ if(!(is_default && no_defaults))
+   Xorriso_status_result(xorriso,filter,fp,flag&2);
+
  is_default= (xorriso->fs==4*512);
  if((xorriso->fs/512)*512==xorriso->fs)
    sprintf(line,"-fs %dm\n", xorriso->fs/512);
@@ -10436,6 +10463,8 @@ int Xorriso_cdrskin_help(struct XorrisO *xorriso, int flag)
 "\t--grow_overwriteable_iso\temulate multi-session on DVD+RW, BD-RE",
 "\twrite_start_address=#\t\twrite to byte address on DVD+RW, BD-RE",
 "\tstream_recording=on\t\ttry to get full speed on DVD-RAM, BD",
+"\tdvd_obs=default|32k|64k\t\tbytes per DVD/BD write operation",
+"\tstdio_sync=on|off|number\twhether to fsync output to \"stdio:\"",
 "\t-help\t\tprint this text to stderr and exit emulation",
 "Actually this is the integrated ISO RockRidge filesystem manipulator xorriso",
 "lending its libburn capabilities to a very limited cdrecord emulation. Only",
@@ -10659,6 +10688,16 @@ no_volunteer:;
      cpt= strchr(argv[i], '=')+1;
      Xorriso_option_stream_recording(xorriso, cpt, 0);
 
+   } else if(strncmp(argv[i], "-dvd_obs=", 9)==0 ||
+             strncmp(argv[i], "dvd_obs=", 8)==0) {
+     cpt= strchr(argv[i], '=') + 1;
+     Xorriso_option_dvd_obs(xorriso, cpt, 0);
+
+   } else if(strncmp(argv[i], "-stdio_sync=", 12)==0 ||
+             strncmp(argv[i], "stdio_sync=", 11)==0) {
+     cpt= strchr(argv[i], '=') + 1;
+     Xorriso_option_stdio_sync(xorriso, cpt, 0);
+
    } else if(strcmp(argv[i], "-toc")==0 || strcmp(argv[i], "--long_toc")==0) {
      do_toc= 1;
    } else if(strncmp(argv[i], "-tsize=", 7)==0 ||
@@ -10943,6 +10982,7 @@ int Xorriso_genisofs_help(struct XorrisO *xorriso, int flag)
 "  -no-emul-boot               Boot image is 'no emulation' image",
 "  -boot-info-table            Patch boot image with info table",
 "  isolinux_mbr=on|auto|off    Control eventual isohybrid MBR generation",
+"  --stdio_sync on|off|number  Control forced output to disk files",
 "  -z, -transparent-compression",
 "                              Enable transparent compression of files",
 "  -v, -verbose                Verbose",
@@ -11131,6 +11171,11 @@ int Xorriso_genisofs(struct XorrisO *xorriso, char *whom,
    } else if(strcmp(argv[i], "-z")==0 ||
              strcmp(argv[i], "-transparent-compression")==0) {
      Xorriso_option_zisofs(xorriso, "by_magic=on", 0);
+   } else if(strcmp(argv[i], "--stdio_sync")==0) {
+     if(i+1>=argc)
+       goto not_enough_args;
+     i++;
+     Xorriso_option_stdio_sync(xorriso, argv[i], 0);
    } else
      was_other_option= 1;
 
@@ -14889,6 +14934,26 @@ int Xorriso_option_dummy(struct XorrisO *xorriso, char *mode, int flag)
 }
 
 
+/* Option -dvd_obs "default"|"32k"|"64k" */
+int Xorriso_option_dvd_obs(struct XorrisO *xorriso, char *obs, int flag)
+{
+ double num;
+
+ if(strcmp(obs, "default") == 0)
+   num= 0;
+ else
+   num = Scanf_io_size(obs,0);
+ if(num != 0 && num != 32768 && num != 65536) {
+   sprintf(xorriso->info_text,
+           "-dvd_obs : Bad size. Acceptable are 0, 32k, 64k");
+   Xorriso_msgs_submit(xorriso, 0, xorriso->info_text, 0, "SORRY", 0);
+   return(0);
+ } else
+   xorriso->dvd_obs= num;
+ return(1);
+}
+
+
 /* Option -eject */
 /* @param flag bit0=do not report toc of eventually remaining drives
 */
@@ -16162,6 +16227,11 @@ int Xorriso_option_help(struct XorrisO *xorriso, int flag)
 "                 Set the burn speed. Default is 0 = maximum speed.",
 "  -stream_recording \"on\"|\"off\"",
 "                 Try to circumvent slow checkread on DVD-RAM, BD-RE, BD-R.",
+"  -dvd_obs \"default\"|\"32k\"|\"64k\"",
+"                 Set number of bytes per DVD/BD write operation.",
+"  -stdio_sync \"on\"|\"off\"|number",
+"                 Set number of bytes after which to force output to stdio",
+"                 pseudo drives. \"on\" is the same as 16m.",
 "  -fs number[\"k\"|\"m\"]",
 "                 Set the size of the fifo buffer. (Default is 4m)",
 "  -eject \"in\"|\"out\"|\"all\"",
@@ -18707,6 +18777,30 @@ int Xorriso_option_status_history_max(struct XorrisO *xorriso, int num,
 }
 
 
+/* Option -stdio_sync "on"|"off"|size */
+int Xorriso_option_stdio_sync(struct XorrisO *xorriso, char *rythm, int flag)
+{
+ double num;
+
+ if(strcmp(rythm, "default") == 0 || strcmp(rythm, "on") == 0)
+   num= 0;
+ if(strcmp(rythm, "off") == 0)
+   num= -1;
+ else
+   num = Scanf_io_size(rythm, 0);
+ if(num > 0)
+   num /= 2048;
+ if(num != -1 && num != 0 && (num < 32 || num > 512 * 1024)) {
+     sprintf(xorriso->info_text,
+             "-stdio_sync : Bad size. Acceptable are -1, 0, 32k ... 1g");
+     Xorriso_msgs_submit(xorriso, 0, xorriso->info_text, 0, "SORRY", 0);
+     return(0);
+ } else
+   xorriso->stdio_sync= num;
+ return(1);
+}
+
+
 /* Option -stream_recording */
 int Xorriso_option_stream_recording(struct XorrisO *xorriso, char *mode,
                                     int flag)
@@ -19249,7 +19343,7 @@ int Xorriso_count_args(struct XorrisO *xorriso, int argc, char **argv,
     "backslash_codes","blank",
     "calm_drive","cd","cdi","cdx","charset","close",
     "commit_eject","compliance",
-    "dev","dialog","disk_dev_ino","disk_pattern","dummy","eject",
+    "dev","dialog","disk_dev_ino","disk_pattern","dummy","dvd_obs","eject",
     "iso_rr_pattern","follow","format","fs","gid","grow_blindly","hardlinks",
     "history","indev","in_charset","joliet",
     "list_delimiter","list_profiles","local_charset",
@@ -19259,7 +19353,7 @@ int Xorriso_count_args(struct XorrisO *xorriso, int argc, char **argv,
     "prog","prog_help","publisher","quoted_not_list","quoted_path_list",
     "reassure","report_about","rom_toc_scan",
     "session_log","speed","split_size","status","status_history_max",
-    "stream_recording","system_id","temp_mem_limit",
+    "stdio_sync","stream_recording","system_id","temp_mem_limit",
     "uid","unregister_filter","use_readline","volid","volset_id",
     "xattr","zisofs",
     ""
@@ -19597,6 +19691,10 @@ next_command:;
    (*idx)++;
    ret= Xorriso_option_dummy(xorriso, arg1, 0);
 
+ } else if(strcmp(cmd,"dvd_obs")==0) {
+   (*idx)++;
+   ret= Xorriso_option_dvd_obs(xorriso, arg1, 0);
+
  } else if(strcmp(cmd,"dux")==0 || strcmp(cmd,"dusx")==0) {
    ret= Xorriso_option_lsx(xorriso, argc, argv, idx, (cmd[2]!='s')|4);
 
@@ -20028,6 +20126,10 @@ next_command:;
    sscanf(arg1,"%d",&num1);
    ret= Xorriso_option_status_history_max(xorriso, num1, 0);
 
+ } else if(strcmp(cmd,"stdio_sync")==0) {
+   (*idx)++;
+   ret= Xorriso_option_stdio_sync(xorriso, arg1, 0);
+
  } else if(strcmp(cmd,"stream_recording")==0) {
    (*idx)++;
    ret= Xorriso_option_stream_recording(xorriso, arg1, 0);
diff --git a/xorriso/xorriso.h b/xorriso/xorriso.h
index 120c0fd8..f335376d 100644
--- a/xorriso/xorriso.h
+++ b/xorriso/xorriso.h
@@ -614,6 +614,9 @@ int Xorriso_option_drive_class(struct XorrisO *xorriso,
 /* Option -dummy "on"|"off" */
 int Xorriso_option_dummy(struct XorrisO *xorriso, char *mode, int flag);
 
+/* Option -dvd_obs "default"|"32k"|"64k" */
+int Xorriso_option_dvd_obs(struct XorrisO *xorriso, char *obs, int flag);
+
 /* Option -eject */
 /* @param flag bit0=do not report toc of eventually remaining drives
 */
@@ -927,6 +930,9 @@ int Xorriso_option_status(struct XorrisO *xorriso, char *mode, int flag);
 int Xorriso_option_status_history_max(struct XorrisO *xorriso, int num1, 
                                       int flag);
 
+/* Option -stdio_sync "on"|"off"|size */
+int Xorriso_option_stdio_sync(struct XorrisO *xorriso, char *rythm, int flag);
+
 /* Option -stream_recording */
 int Xorriso_option_stream_recording(struct XorrisO *xorriso, char *mode,
                                     int flag);
diff --git a/xorriso/xorriso_private.h b/xorriso/xorriso_private.h
index 76793539..976f77f1 100644
--- a/xorriso/xorriso_private.h
+++ b/xorriso/xorriso_private.h
@@ -259,6 +259,9 @@ struct XorrisO { /* the global context of xorriso */
  int do_stream_recording; /* 0=no, 1=yes, 2=for data, not for dir
                              >=16 means yes with number as start LBA  */
 
+ int dvd_obs;                 /* DVD write chunk size: 0, 32k or 64k */
+ int stdio_sync;              /* stdio fsync interval: -1, 0, >=32 */
+
  int keep_boot_image;
  int patch_isolinux_image;
  char boot_image_bin_path[SfileadrL];
diff --git a/xorriso/xorriso_timestamp.h b/xorriso/xorriso_timestamp.h
index 16189b2b..b4d72e75 100644
--- a/xorriso/xorriso_timestamp.h
+++ b/xorriso/xorriso_timestamp.h
@@ -1 +1 @@
-#define Xorriso_timestamP "2009.11.17.123150"
+#define Xorriso_timestamP "2009.11.17.134239"
diff --git a/xorriso/xorrisoburn.c b/xorriso/xorrisoburn.c
index f0b3ac68..6fbeca25 100644
--- a/xorriso/xorrisoburn.c
+++ b/xorriso/xorrisoburn.c
@@ -1445,6 +1445,15 @@ int Xorriso_make_write_options(
  else if(xorriso->do_stream_recording >= 16)
    stream_mode= xorriso->do_stream_recording;
  burn_write_opts_set_stream_recording(*burn_options, stream_mode);
+
+#ifdef Xorriso_dvd_obs_default_64K
+ if(xorriso->dvd_obs == 0)
+   burn_write_opts_set_dvd_obs(*burn_options, 64 * 1024);
+ else  
+#endif
+   burn_write_opts_set_dvd_obs(*burn_options, xorriso->dvd_obs);
+
+ burn_write_opts_set_stdio_fsync(*burn_options, xorriso->stdio_sync);
  burn_write_opts_set_underrun_proof(*burn_options, 1);
  return(1);
 }