diff --git a/cdrskin/cdrskin_timestamp.h b/cdrskin/cdrskin_timestamp.h
index 40f1acc..5211c5a 100644
--- a/cdrskin/cdrskin_timestamp.h
+++ b/cdrskin/cdrskin_timestamp.h
@@ -1 +1 @@
-#define Cdrskin_timestamP "2009.11.11.105028"
+#define Cdrskin_timestamP "2009.11.12.175514"
diff --git a/libburn/init.c b/libburn/init.c
index 32ecb02..d84e776 100644
--- a/libburn/init.c
+++ b/libburn/init.c
@@ -75,6 +75,13 @@ burn_abort_handler_t burn_global_signal_handler = NULL;
 /* ts A70223 : wether implemented untested profiles are supported */
 int burn_support_untested_profiles = 0;
 
+/* ts A91111 :
+   whether to log SCSI commands (to be implemented in sg-*.c)
+   bit0= log in /tmp/libburn_sg_command_log
+   bit1= log to stderr
+   bit2= flush every line
+*/
+int burn_sg_log_scsi = 0;
 
 /* ts A60925 : ticket 74 */
 /** Create the messenger object for libburn. */
@@ -414,3 +421,9 @@ int burn_set_messenger(void *messenger)
 	return 1;
 }
 
+
+/* ts A91111 API */
+void burn_set_scsi_logging(int flag)
+{
+	burn_sg_log_scsi = flag & 7;
+}
diff --git a/libburn/libburn.h b/libburn/libburn.h
index 3909f33..1a46f9e 100644
--- a/libburn/libburn.h
+++ b/libburn/libburn.h
@@ -762,6 +762,19 @@ int burn_abort_pacifier(void *handle, int patience, int elapsed);
 */
 void burn_set_verbosity(int level);
 
+/* ts A91111 */
+/** Enable resp. disable logging of SCSI commands (currently Linux only).
+    This call can be made at any time - even before burn_initialize().
+    It is in effect for all active drives and currently not very thread
+    safe for multiple drives.
+    @param flag  Bitfield for control purposes. The default is 0.
+                 bit0= log to file /tmp/libburn_sg_command_log
+                 bit1= log to stderr
+                 bit2= flush output after each line
+    @since 0.7.4
+*/
+void burn_set_scsi_logging(int flag);
+
 /* ts A60813 */
 /** Set parameters for behavior on opening device files. To be called early
     after burn_initialize() and before any bus scan. But not mandatory at all.
@@ -2772,12 +2785,21 @@ BURN_END_DECLS
    # define Libburn_pioneer_dvr_216d_get_evenT 1
 */
 
-/* Probing of CD write modes hampers ejecting of the drive tray.
-   Needed is a more intelligent management of probing.
-   Note to myself: check whether feature interpretation can replace probing
+/* ts A91112 */
+/* Do not probe CD modes but declare only data and audio modes supported.
+   For other modes resp. real probing one has to call
+   burn_drive_probe_cd_write_modes().
 
-   # define Libburn_pioneer_dvr_216d_no_probe_wM 1
+   # define Libburn_pioneer_dvr_216d_dummy_probe_wM 1
 */
+#ifdef Libburn_pioneer_dvr_216d_dummy_probe_wM
+
+/* Probe available CD write modes and block types.
+   @param drive_info  drive object to be inquired
+*/
+int burn_drive_probe_cd_write_modes(struct burn_drive_info *drive_info)
+
+#endif /* Libburn_pioneer_dvr_216d_dummy_probe_wM */
 
 
 #endif /*LIBBURN_H*/
diff --git a/libburn/sg-linux.c b/libburn/sg-linux.c
index 1ef7822..7322554 100644
--- a/libburn/sg-linux.c
+++ b/libburn/sg-linux.c
@@ -1,5 +1,11 @@
 /* -*- indent-tabs-mode: t; tab-width: 8; c-basic-offset: 8; -*- */
 
+
+/* <<< ts A91112 : experiments to get better speed with USB
+#define Libburn_sgio_as_growisofS 1
+*/
+
+
 /*
 
 This is the main operating system dependent SCSI part of libburn. It implements
@@ -196,17 +202,25 @@ static void enumerate_common(char *fname, int bus_no, int host_no,
 
 
 /* ts A60813 : storage objects are in libburn/init.c
-   wether to use O_EXCL with open(2) of devices
-   wether to use fcntl(,F_SETLK,) after open(2) of devices
+   whether to use O_EXCL with open(2) of devices
+   whether to use fcntl(,F_SETLK,) after open(2) of devices
    what device family to use : 0=default, 1=sr, 2=scd, (3=st), 4=sg
-   wether to use O_NOBLOCK with open(2) on devices
-   wether to take O_EXCL rejection as fatal error */
+   whether to use O_NOBLOCK with open(2) on devices
+   whether to take O_EXCL rejection as fatal error
+*/
 extern int burn_sg_open_o_excl;
 extern int burn_sg_fcntl_f_setlk;
 extern int burn_sg_use_family;
 extern int burn_sg_open_o_nonblock;
 extern int burn_sg_open_abort_busy;
 
+/* ts A91111 :
+   whether to log SCSI commands:
+   bit0= log in /tmp/libburn_sg_command_log
+   bit1= log to stderr
+   bit2= flush every line
+*/
+extern int burn_sg_log_scsi;
 
 /* ts A60821
    debug: for tracing calls which might use open drive fds
@@ -1642,6 +1656,7 @@ int sg_release(struct burn_drive *d)
 }
 
 
+/* <<< ts A91111: on its way out */
 /** ts A70518: 
     Debugging log facility. Controlled by existence of macros:
      Libburn_log_sg_commandS          enables logging to file
@@ -1650,10 +1665,11 @@ int sg_release(struct burn_drive *d)
      Libburn_log_sg_command_stderR    enables additional log to stderr
 */
 /*
+ ts A91111: now enabled by default and controlled burn_sg_log_scsi
+*/
 #define Libburn_log_sg_commandS 1
 #define Libburn_fflush_log_sg_commandS 1
 #define Libburn_log_sg_command_stderR 1
-*/
 
 
 #ifdef Libburn_log_sg_commandS
@@ -1661,16 +1677,16 @@ int sg_release(struct burn_drive *d)
 /** Logs command (before execution) */
 static int sg_log_cmd(struct command *c, FILE *fp, int flag)
 {
-
-	if (fp != NULL) {
+	if (fp != NULL && (fp == stderr || (burn_sg_log_scsi & 1))) {
 		scsi_show_cmd_text(c, fp, 0);
 
 #ifdef Libburn_fflush_log_sg_commandS
-		fflush(fp);
+		if (burn_sg_log_scsi & 4)
+			fflush(fp);
 #endif
 	}
 #ifdef Libburn_log_sg_command_stderR
-	if (fp == stderr)
+	if (fp == stderr || !(burn_sg_log_scsi & 2))
 		return 1;
 	sg_log_cmd(c, stderr, flag);
 #endif
@@ -1683,7 +1699,7 @@ static int sg_log_err(struct command *c, FILE *fp,
 		sg_io_hdr_t *s,
 		int flag)
 {
-      	if(fp!=NULL) {
+      	if(fp != NULL && (fp == stderr || (burn_sg_log_scsi & 1))) {
 		if(flag & 1) {
   			fprintf(fp,
 			"+++ key=%X  asc=%2.2Xh  ascq=%2.2Xh   (%6d ms)\n",
@@ -1693,11 +1709,12 @@ static int sg_log_err(struct command *c, FILE *fp,
 			fprintf(fp,"%6d ms\n", s->duration);
 		}
 #ifdef Libburn_fflush_log_sg_commandS
-		fflush(fp);
+		if (burn_sg_log_scsi & 4)
+			fflush(fp);
 #endif
 	}
 #ifdef Libburn_log_sg_command_stderR
-	if (fp == stderr)
+	if (fp == stderr || !(burn_sg_log_scsi & 2))
 		return 1;
 	sg_log_err(c, stderr, s, flag);
 #endif
@@ -1738,11 +1755,15 @@ int sg_issue_command(struct burn_drive *d, struct command *c)
 
 #ifdef Libburn_log_sg_commandS
 	/* ts A61030 */
-	if(fp==NULL) {
-		fp= fopen("/tmp/libburn_sg_command_log","a");
-		fprintf(fp,"\n-----------------------------------------\n");
+	if (burn_sg_log_scsi & 1) {
+		if (fp == NULL) {
+			fp= fopen("/tmp/libburn_sg_command_log", "a");
+			fprintf(fp,
+			    "\n-----------------------------------------\n");
+		}
 	}
-	sg_log_cmd(c,fp,0);
+	if (burn_sg_log_scsi & 3)
+		sg_log_cmd(c,fp,0);
 #endif /* Libburn_log_sg_commandS */
 	  
 
@@ -1757,6 +1778,13 @@ int sg_issue_command(struct burn_drive *d, struct command *c)
 
 	s.interface_id = 'S';
 
+#ifdef Libburn_sgio_as_growisofS
+	/* ??? ts A91112 : does this speed up USB ? (from growisofs)
+	--- did not help
+	 */
+	s.flags = SG_FLAG_DIRECT_IO;
+#endif /* Libburn_sgio_as_growisofS */
+
 	if (c->dir == TO_DRIVE)
 		s.dxfer_direction = SG_DXFER_TO_DEV;
 	else if (c->dir == FROM_DRIVE)
@@ -1879,7 +1907,8 @@ ex:;
 	}
 
 #ifdef Libburn_log_sg_commandS
-	sg_log_err(c, fp, &s, c->error != 0);
+	if (burn_sg_log_scsi & 3)
+		sg_log_err(c, fp, &s, c->error != 0);
 #endif /* Libburn_log_sg_commandS */
 
 	return 1;
diff --git a/libburn/write.c b/libburn/write.c
index c9a4eda..a89247a 100644
--- a/libburn/write.c
+++ b/libburn/write.c
@@ -1255,7 +1255,7 @@ int burn_dvd_write_track(struct burn_write_opts *o,
 	struct buffer *out = d->buffer;
 	int sectors;
 	int i, open_ended = 0, ret= 0, is_flushed = 0;
-	int first_buf_cap = 0, further_cap = 0;
+	int first_buf_cap = 0, further_cap = 0, buf_cap_step = 256;
 
 	/* ts A70213 : eventually expand size of track to max */
 	burn_track_apply_fillup(t, d->media_capacity_remaining, 0);
@@ -1314,7 +1314,8 @@ int burn_dvd_write_track(struct burn_write_opts *o,
 		              before the drive buffer is full. See above DVD-
 		*/
 		if (i == first_buf_cap ||
-		   ((i % 256) == 0 && (i >= further_cap || further_cap < 0))) {
+		   ((i % buf_cap_step) == 0 &&
+		    (i >= further_cap || further_cap < 0))) {
 			d->read_buffer_capacity(d);
 			if (further_cap < 0)
 				further_cap =
@@ -1787,8 +1788,10 @@ int burn_dvd_write_sync(struct burn_write_opts *o,
 
 	/* <<< test only : Does this increase effective speed with USB ?
 		ts A90801 : 64kB: speed with 16x DVD-R is 12 rather than 8
-		>>> next try is 128 kB
-	o->obs = 128 * 1024;
+		            128kB: glibc complains about double free
+		                   BURN_OS_TRANSPORT_BUFFER_SIZE would need to
+		                   be enlarged anyway.
+	o->obs = 64 * 1024;
 	*/