diff --git a/PDP10/pdp10_rp.c b/PDP10/pdp10_rp.c
index 82dc32f6..56c9d8f1 100644
--- a/PDP10/pdp10_rp.c
+++ b/PDP10/pdp10_rp.c
@@ -1177,8 +1177,7 @@ t_stat r;
 static const char *drives[] = {"RM03", "RP04", "RM80", "RP06", "RM05", "RP07", NULL};
 
 uptr->capac = drv_tab[GET_DTYPE (uptr->flags)].size;
-r = sim_disk_pdp10_attach (uptr, cptr, RP_NUMWD * sizeof (d10), sizeof (d10),
-                           (uptr->flags & UNIT_AUTO) == 0, DBG_DSK,
+r = sim_disk_pdp10_attach (uptr, cptr, (uptr->flags & UNIT_AUTO) == 0, DBG_DSK,
                            drv_tab[GET_DTYPE (uptr->flags)].name,
                            0, (uptr->flags & UNIT_AUTO) ? drives : NULL);
 if (r != SCPE_OK)
diff --git a/sim_disk.c b/sim_disk.c
index 99a4c561..38cc708f 100644
--- a/sim_disk.c
+++ b/sim_disk.c
@@ -2600,6 +2600,22 @@ return SCPE_OK;
 
 t_stat sim_disk_attach_help(FILE *st, DEVICE *dptr, UNIT *uptr, int32 flag, const char *cptr)
 {
+static struct example_fields {
+    const char *dname;
+    const char *dtype;
+    const char *dsize;
+    const char *dtype2;
+    const char *dsize2;
+    const char *dtype3;
+    const char *dsize3;
+    const char *dtype4;
+    const char *dsize4;
+    } ex_data[2] = {
+        {"RQ", "RD54",     "159MB", "RX50",    "409KB", "RA81", "456MB", "RA92", "1505MB"},
+        {"RP", "autosize", "39MW",  "autosize", "39MW", "RP07", "110MW", "RM03", "15MW"},
+    };
+struct example_fields *ex = &ex_data[0];
+
 fprintf (st, "%s Disk Attach Help\n\n", dptr->name);
 
 fprintf (st, "Disk container files can be one of 3 different types:\n\n");
@@ -2676,54 +2692,68 @@ fprintf (st, "    -M          Merge a Differencing VHD into its parent VHD disk\
 fprintf (st, "    -O          Override consistency checks when attaching differencing disks\n");
 fprintf (st, "                which have unexpected parent disk GUID or timestamps\n\n");
 fprintf (st, "    -U          Fix inconsistencies which are overridden by the -O switch\n");
-fprintf (st, "    -Y          Answer Yes to prompt to overwrite last track (on disk create)\n");
-fprintf (st, "    -N          Answer No to prompt to overwrite last track (on disk create)\n");
+if (strstr (sim_name, "PDP10") == NULL) {
+    fprintf (st, "    -Y          Answer Yes to prompt to overwrite last track (on disk create)\n");
+    fprintf (st, "    -N          Answer No to prompt to overwrite last track (on disk create)\n");
+    }
+if (strstr (sim_name, "PDP10-")) {
+    ex = &ex_data[1];
+    ex->dname = "RPA";
+    }
+if (strcmp (dptr->name, "RP") == 0)
+    ex = &ex_data[1];
 fprintf (st, "Examples:\n");
-fprintf (st, "  sim> show rq\n");
-fprintf (st, "    RQ, address=20001468-2000146B*, no vector, 4 units\n");
-fprintf (st, "    RQ0, 159MB, not attached, write enabled, RD54, autosize, SIMH format\n");
-fprintf (st, "    RQ1, 159MB, not attached, write enabled, RD54, autosize, SIMH format\n");
-fprintf (st, "    RQ2, 159MB, not attached, write enabled, RD54, autosize, SIMH format\n");
-fprintf (st, "    RQ3, 409KB, not attached, write enabled, RX50, autosize, SIMH format\n");
-fprintf (st, "  sim> atta rq0 RA81.vhd\n");
-fprintf (st, "  sim> show rq0\n");
-fprintf (st, "  RQ0, 456MB, attached to RA81.vhd, write enabled, RA81, autosize, VHD format\n");
-fprintf (st, "  sim> set rq2 ra92\n");
-fprintf (st, "  sim> att rq2 -f vhd RA92.vhd\n");
-fprintf (st, "  RQ2: creating new file\n");
-fprintf (st, "  sim> sho rq2\n");
-fprintf (st, "  RQ2, 1505MB, attached to RA92.vhd, write enabled, RA92, autosize, VHD format\n");
-fprintf (st, "  sim> dir RA92.vhd\n");
+fprintf (st, "  sim> show %s\n", ex->dname);
+fprintf (st, "    %s, address=20001468-2000146B*, no vector, 4 units\n", ex->dname);
+fprintf (st, "    %s0, %s, not attached, write enabled, %s, autosize, SIMH format\n", ex->dname, ex->dsize, ex->dtype);
+fprintf (st, "    %s1, %s, not attached, write enabled, %s, autosize, SIMH format\n", ex->dname, ex->dsize, ex->dtype);
+fprintf (st, "    %s2, %s, not attached, write enabled, %s, autosize, SIMH format\n", ex->dname, ex->dsize, ex->dtype);
+fprintf (st, "    %s3, %s, not attached, write enabled, %s, autosize, SIMH format\n", ex->dname, ex->dsize2, ex->dtype2);
+fprintf (st, "  sim> # attach an existing VHD and determine its size and type automatically\n");
+fprintf (st, "  sim> attach %s0 %s.vhd\n", ex->dname, ex->dtype3);
+fprintf (st, "  sim> show %s0\n", ex->dname);
+fprintf (st, "  %s0, %s, attached to %s.vhd, write enabled, %s, autosize, VHD format\n", ex->dname, ex->dsize3, ex->dtype3, ex->dtype3);
+fprintf (st, "  sim> # create a new %s drive type VHD\n", ex->dtype4);
+fprintf (st, "  sim> set %s2 %s\n", ex->dname, ex->dtype4);
+fprintf (st, "  sim> attach %s2 -f vhd %s.vhd\n", ex->dname, ex->dtype4);
+fprintf (st, "  %s2: creating new file\n", ex->dname);
+fprintf (st, "  sim> show %s2\n", ex->dname);
+fprintf (st, "  %s2, %s, attached to %s.vhd, write enabled, %s, autosize, VHD format\n", ex->dname, ex->dsize4, ex->dtype4, ex->dtype4);
+fprintf (st, "  sim> # examine the size consumed by the %s VHD file", ex->dsize4);
+fprintf (st, "  sim> dir %s.vhd\n", ex->dtype4);
 fprintf (st, "   Directory of H:\\Data\n\n");
-fprintf (st, "  04/14/2011  12:57 PM             5,120 RA92.vhd\n");
+fprintf (st, "  04/14/2011  12:57 PM             5,120 %s.vhd\n", ex->dtype4);
 fprintf (st, "                 1 File(s)          5,120 bytes\n");
-fprintf (st, "  sim> atta rq3 -d RA92-1-Diff.vhd RA92.vhd\n");
-fprintf (st, "  sim> atta rq3 -c RA92-1.vhd RA92.vhd\n");
-fprintf (st, "  RQ3: creating new virtual disk 'RA92-1.vhd'\n");
-fprintf (st, "  RQ3: Copied 1505MB.  99%% complete.\n");
-fprintf (st, "  RQ3: Copied 1505MB. Done.\n");
-fprintf (st, "  sim> sh rq3\n");
-fprintf (st, "  RQ3, 1505MB, attached to RA92-1.vhd, write enabled, RA92, autosize, VHD format\n");
-fprintf (st, "  sim> dir RA92*\n");
+fprintf (st, "  sim> # create a differencing vhd (%s-1-Diff.vhd) with %s.vhd as parent\n", ex->dtype4, ex->dtype4);
+fprintf (st, "  sim> attach %s3 -d %s-1-Diff.vhd %s.vhd\n", ex->dname, ex->dtype4, ex->dtype4);
+fprintf (st, "  sim> # create a VHD (%s-1.vhd) which is a copy of an existing disk\n", ex->dtype4);
+fprintf (st, "  sim> attach %s3 -c %s-1.vhd %s.vhd\n", ex->dname, ex->dtype4, ex->dtype4);
+fprintf (st, "  %s3: creating new virtual disk '%s-1.vhd'\n", ex->dname, ex->dsize4);
+fprintf (st, "  %s3: Copied %s.  99%% complete.\n", ex->dname, ex->dsize4);
+fprintf (st, "  %s3: Copied %s. Done.\n", ex->dname, ex->dsize4);
+fprintf (st, "  sim> show %s3\n", ex->dname);
+fprintf (st, "  %s3, %s, attached to %s-1.vhd, write enabled, %s, autosize, VHD format\n", ex->dname, ex->dsize3, ex->dtype3, ex->dtype3);
+fprintf (st, "  sim> dir %s*\n", ex->dtype3);
 fprintf (st, "   Directory of H:\\Data\n\n");
-fprintf (st, "  04/14/2011  01:12 PM             5,120 RA92-1.vhd\n");
-fprintf (st, "  04/14/2011  12:58 PM             5,120 RA92.vhd\n");
+fprintf (st, "  04/14/2011  01:12 PM             5,120 %s-1.vhd\n", ex->dtype3);
+fprintf (st, "  04/14/2011  12:58 PM             5,120 %s.vhd\n", ex->dtype3);
 fprintf (st, "                 2 File(s)         10,240 bytes\n");
-fprintf (st, "  sim> sho rq2\n");
-fprintf (st, "  RQ2, 1505MB, not attached, write enabled, RA92, autosize, VHD format\n");
-fprintf (st, "  sim> set rq2 ra81\n");
-fprintf (st, "  sim> set rq2 noauto\n");
-fprintf (st, "  sim> sho rq2\n");
-fprintf (st, "  RQ2, 456MB, not attached, write enabled, RA81, noautosize, VHD format\n");
-fprintf (st, "  sim> set rq2 format=simh\n");
-fprintf (st, "  sim> sho rq2\n");
-fprintf (st, "  RQ2, 456MB, not attached, write enabled, RA81, noautosize, SIMH format\n");
-fprintf (st, "  sim> atta rq2 -c RA81-Copy.vhd VMS055.dsk\n");
-fprintf (st, "  RQ2: creating new virtual disk 'RA81-Copy.vhd'\n");
-fprintf (st, "  RQ2: Copied 456MB.  99%% complete.\n");
-fprintf (st, "  RQ2: Copied 456MB. Done.\n");
-fprintf (st, "  sim> sho rq2\n");
-fprintf (st, "  RQ2, 456MB, attached to RA81-Copy.vhd, write enabled, RA81, noautosize, VHD format\n");
+fprintf (st, "  sim> show %s2\n", ex->dname);
+fprintf (st, "  %s2, %s, not attached, write enabled, %s, autosize, VHD format\n", ex->dname, ex->dsize4, ex->dtype4);
+fprintf (st, "  sim> set %s2 %s\n", ex->dname, ex->dtype3);
+fprintf (st, "  sim> set %s2 noauto\n", ex->dname);
+fprintf (st, "  sim> show %s2\n", ex->dname);
+fprintf (st, "  %s2, %s, not attached, write enabled, %s, noautosize, VHD format\n", ex->dname, ex->dsize3, ex->dtype3);
+fprintf (st, "  sim> set %s2 format=simh\n", ex->dname);
+fprintf (st, "  sim> show %s2\n", ex->dname);
+fprintf (st, "  %s2, %s, not attached, write enabled, %s, noautosize, SIMH format\n", ex->dname, ex->dsize3, ex->dtype3);
+fprintf (st, "  sim> # create a VHD from an existing SIMH format disk\n");
+fprintf (st, "  sim> attach %s2 -c %s-Copy.vhd XYZZY.dsk\n", ex->dname, ex->dtype3);
+fprintf (st, "  %s2: creating new virtual disk '%s-Copy.vhd'\n", ex->dname, ex->dtype3);
+fprintf (st, "  %s2: Copied %s.  99%% complete.\n", ex->dname, ex->dsize3);
+fprintf (st, "  %s2: Copied %s. Done.\n", ex->dname, ex->dsize3);
+fprintf (st, "  sim> show %s2\n", ex->dname);
+fprintf (st, "  %s2, %s, attached to %s-Copy.vhd, write enabled, %s, noautosize, VHD format\n", ex->dname, ex->dsize3, ex->dtype3, ex->dtype3);
 return SCPE_OK;
 }
 
@@ -2880,10 +2910,10 @@ if (sim_deb && (dptr->dctrl & reason)) {
 /* Guest specific Disk I/O support */
 #define PDP10_SECTORS   2               /* PDP-10 sectors are 1024 bytes */
 
-t_stat sim_disk_pdp10_attach (UNIT *uptr, const char *cptr, size_t sector_size, size_t xfer_element_size, t_bool dontautosize,
+t_stat sim_disk_pdp10_attach (UNIT *uptr, const char *cptr, t_bool dontautosize,
                            uint32 dbit, const char *dtype, int completion_delay, const char **drivetypes)
 {
-return sim_disk_attach_ex (uptr, cptr, sector_size / PDP10_SECTORS, xfer_element_size, dontautosize, dbit, dtype, 0, completion_delay, drivetypes);
+return sim_disk_attach_ex (uptr, cptr, 512 * PDP10_SECTORS, sizeof (t_uint64), dontautosize, dbit, dtype, 0, completion_delay, drivetypes);
 }
 
 t_stat sim_disk_pdp10_rdsect (UNIT *uptr, t_lba lba, uint8 *buf, t_seccnt *sectsread, t_seccnt sects)
diff --git a/sim_disk.h b/sim_disk.h
index 9307b85b..e0a8db0d 100644
--- a/sim_disk.h
+++ b/sim_disk.h
@@ -97,8 +97,8 @@ t_bool sim_disk_vhd_support (void);
 t_bool sim_disk_raw_support (void);
 void sim_disk_data_trace (UNIT *uptr, const uint8 *data, size_t lba, size_t len, const char* txt, int detail, uint32 reason);
 t_stat sim_disk_test (DEVICE *dptr);
-t_stat sim_disk_pdp10_attach (UNIT *uptr, const char *cptr, size_t sector_size, size_t xfer_element_size, t_bool dontautosize,
-                                 uint32 dbit, const char *dtype, int completion_delay, const char **drivetypes);
+t_stat sim_disk_pdp10_attach (UNIT *uptr, const char *cptr, t_bool dontautosize, uint32 dbit, 
+                              const char *dtype, int completion_delay, const char **drivetypes);
 t_stat sim_disk_pdp10_rdsect (UNIT *uptr, t_lba lba, uint8 *buf, t_seccnt *sectsread, t_seccnt sects);
 t_stat sim_disk_pdp10_wrsect (UNIT *uptr, t_lba lba, uint8 *buf, t_seccnt *sectswritten, t_seccnt sects);