diff --git a/PDP11/pdp11_hk.c b/PDP11/pdp11_hk.c
index 7c9686e5..72c74a6f 100644
--- a/PDP11/pdp11_hk.c
+++ b/PDP11/pdp11_hk.c
@@ -1497,11 +1497,13 @@ uint32 drv;
 t_offset p;
 t_stat r;
 int32 old_hkds;
+static const char *drives[] = {"RK06", "RK07", NULL};
 
 uptr->capac = HK_SIZE (uptr);
-r = sim_disk_attach (uptr, cptr, HK_NUMWD * sizeof (uint16), 
-                     sizeof (uint16), TRUE, 0, 
-                     (uptr->capac == RK06_SIZE) ? "RK06" : "RK07", HK_NUMSC, 0);
+r = sim_disk_attach_ex (uptr, cptr, HK_NUMWD * sizeof (uint16), 
+                        sizeof (uint16), TRUE, 0, 
+                        (uptr->capac == RK06_SIZE) ? "RK06" : "RK07", HK_NUMSC, 0,
+                        (uptr->flags & UNIT_AUTO) ? drives : NULL);
 if (r != SCPE_OK)                                       /* error? */
     return r;
 drv = (uint32) (uptr - hk_dev.units);                   /* get drv number */
diff --git a/PDP11/pdp11_rl.c b/PDP11/pdp11_rl.c
index e78df7c1..fb0f522b 100644
--- a/PDP11/pdp11_rl.c
+++ b/PDP11/pdp11_rl.c
@@ -1017,11 +1017,13 @@ t_stat rl_attach (UNIT *uptr, CONST char *cptr)
 {
 t_offset p;
 t_stat r;
+static const char *drives[] = {"RL01", "RL02", NULL};
 
 uptr->capac = (uptr->flags & UNIT_RL02)? RL02_SIZE: RL01_SIZE;
-r = sim_disk_attach (uptr, cptr, RL_NUMWD * sizeof (uint16), 
-                     sizeof (uint16), TRUE, 0, 
-                     (uptr->capac == RL02_SIZE) ? "RL02" : "RL01", RL_NUMSC, 0);
+r = sim_disk_attach_ex (uptr, cptr, RL_NUMWD * sizeof (uint16), 
+                        sizeof (uint16), TRUE, 0, 
+                        (uptr->capac == RL02_SIZE) ? "RL02" : "RL01", RL_NUMSC, 0,
+                        (uptr->flags & UNIT_AUTO) ? drives : NULL);
 if (r != SCPE_OK)                                       /* error? */
     return r;
 /*
diff --git a/PDP11/pdp11_rp.c b/PDP11/pdp11_rp.c
index f1753726..b8a74286 100644
--- a/PDP11/pdp11_rp.c
+++ b/PDP11/pdp11_rp.c
@@ -1378,11 +1378,12 @@ t_stat rp_attach (UNIT *uptr, CONST char *cptr)
 int32 drv, i, p;
 t_stat r;
 DEVICE *dptr = find_dev_from_unit (uptr);
+static const char *drives[] = {"RM03", "RP04", "RM80", "RP06", "RM05", "RP07", NULL};
 
 uptr->capac = drv_tab[GET_DTYPE (uptr->flags)].size;
-r = sim_disk_attach (uptr, cptr, RP_NUMWD * sizeof (uint16), 
-                     sizeof (uint16), TRUE, 0, 
-                     drv_tab[GET_DTYPE (uptr->flags)].name, drv_tab[GET_DTYPE (uptr->flags)].sect, 0);
+r = sim_disk_attach_ex (uptr, cptr, RP_NUMWD * sizeof (uint16), 
+                        sizeof (uint16), TRUE, 0, 
+                        drv_tab[GET_DTYPE (uptr->flags)].name, drv_tab[GET_DTYPE (uptr->flags)].sect, 0, (uptr->flags & UNIT_AUTO) ? drives : NULL);
 if (r != SCPE_OK)                                       /* error? */
     return r;
 drv = (int32) (uptr - dptr->units);                     /* get drv number */
diff --git a/doc/simh.doc b/doc/simh.doc
index 27e177f3..9cd375c4 100644
Binary files a/doc/simh.doc and b/doc/simh.doc differ
diff --git a/scp.c b/scp.c
index f86ba86a..7781648a 100644
--- a/scp.c
+++ b/scp.c
@@ -759,6 +759,7 @@ const struct scp_error {
          {"REMOTE",  "remote console command"},
          {"INVEXPR", "invalid expression"},
          {"SIGTERM", "SIGTERM received"},
+         {"FSSIZE",  "File System size larger than disk size"},
     };
 
 const size_t size_map[] = { sizeof (int8),
diff --git a/sim_defs.h b/sim_defs.h
index 21f0e431..29666336 100644
--- a/sim_defs.h
+++ b/sim_defs.h
@@ -416,8 +416,9 @@ typedef uint32          t_addr;
 #define SCPE_REMOTE     (SCPE_BASE + 46)                /* remote console command */
 #define SCPE_INVEXPR    (SCPE_BASE + 47)                /* invalid expression */
 #define SCPE_SIGTERM    (SCPE_BASE + 48)                /* SIGTERM has been received */
+#define SCPE_FSSIZE     (SCPE_BASE + 49)                /* File System size larger than disk size */
 
-#define SCPE_MAX_ERR    (SCPE_BASE + 48)                /* Maximum SCPE Error Value */
+#define SCPE_MAX_ERR    (SCPE_BASE + 49)                /* Maximum SCPE Error Value */
 #define SCPE_KFLAG      0x10000000                      /* tti data flag */
 #define SCPE_BREAK      0x20000000                      /* tti break flag */
 #define SCPE_NOMESSAGE  0x40000000                      /* message display supression flag */
diff --git a/sim_disk.c b/sim_disk.c
index 48618ffb..d75220b5 100644
--- a/sim_disk.c
+++ b/sim_disk.c
@@ -1444,7 +1444,7 @@ for (part = 0; part < RT11_MAXPARTITIONS; part++) {
 
             dir_sec = Home.hb_w_firstdir + ((dir_seg - 1) * 2);
 
-            if (sim_disk_rdsect(uptr, (base + dir_sec) * (512 / ctx->sector_size), sector_buf, &sects_read, 1024 / ctx->sector_size) ||
+            if ((sim_disk_rdsect(uptr, (base + dir_sec) * (512 / ctx->sector_size), sector_buf, &sects_read, 1024 / ctx->sector_size)) ||
                 (sects_read != (1024 / ctx->sector_size)))
                 goto Return_Cleanup;
 
@@ -1545,6 +1545,12 @@ return ret_val;
 t_stat sim_disk_attach (UNIT *uptr, const char *cptr, size_t sector_size, size_t xfer_element_size, t_bool dontautosize,
                         uint32 dbit, const char *dtype, uint32 pdp11tracksize, int completion_delay)
 {
+return sim_disk_attach_ex (uptr, cptr, sector_size, xfer_element_size, dontautosize, dbit, dtype, pdp11tracksize, completion_delay, NULL);
+}
+
+t_stat sim_disk_attach_ex (UNIT *uptr, const char *cptr, size_t sector_size, size_t xfer_element_size, t_bool dontautosize,
+                           uint32 dbit, const char *dtype, uint32 pdp11tracksize, int completion_delay, const char **drivetypes)
+{
 struct disk_context *ctx;
 DEVICE *dptr;
 char tbuf[4*CBUFSIZE];
@@ -1976,16 +1982,34 @@ if (container_size && (container_size != (t_offset)-1)) {
     if (dontautosize) {
         t_addr saved_capac = uptr->capac;
 
-        if ((filesystem_size != (t_offset)-1) &&
-            (filesystem_size > current_unit_size)) {
-            if (!sim_quiet) {
-                uptr->capac = (t_addr)(filesystem_size/(ctx->capac_factor*((dptr->flags & DEV_SECTORS) ? 512 : 1)));
-                sim_printf ("%s%d: The file system on the disk %s is larger than simulated device (%s > ", sim_dname (dptr), (int)(uptr-dptr->units), cptr, sprint_capac (dptr, uptr));
-                uptr->capac = saved_capac;
-                sim_printf ("%s)\n", sprint_capac (dptr, uptr));
+        if (filesystem_size != (t_offset)-1) {
+            const char *drive_type = NULL;
+
+            while ((filesystem_size > current_unit_size) &&
+                   ((drivetypes ? *drivetypes : NULL) != NULL)) {
+                char cmd[CBUFSIZE];
+                t_stat st;
+
+                uptr->flags &= ~UNIT_ATT;   /* temporarily mark as un-attached */
+                drive_type = *drivetypes;
+                sprintf (cmd, "%s %s", sim_uname (uptr), *drivetypes);
+                st = set_cmd (0, cmd);
+                uptr->flags |= UNIT_ATT;    /* restore attached indicator */
+                if (st == SCPE_OK) {
+                    current_unit_size = ((t_offset)uptr->capac)*ctx->capac_factor*((dptr->flags & DEV_SECTORS) ? 512 : 1);
+                    ++drivetypes;                           /* next type */
+                    }
+                }
+            if (filesystem_size > current_unit_size) {
+                if (!sim_quiet) {
+                    uptr->capac = (t_addr)(filesystem_size/(ctx->capac_factor*((dptr->flags & DEV_SECTORS) ? 512 : 1)));
+                    sim_printf ("%s%d: The file system on the disk %s is larger than simulated device (%s > ", sim_dname (dptr), (int)(uptr-dptr->units), cptr, sprint_capac (dptr, uptr));
+                    uptr->capac = saved_capac;
+                    sim_printf ("%s)\n", sprint_capac (dptr, uptr));
+                    }
+                sim_disk_detach (uptr);
+                return SCPE_FSSIZE;
                 }
-            sim_disk_detach (uptr);
-            return SCPE_OPENERR;
             }
         if ((container_size < current_unit_size) && 
             ((DKUF_F_VHD == DK_GET_FMT (uptr)) || (0 != (uptr->flags & UNIT_RO)))) {
diff --git a/sim_disk.h b/sim_disk.h
index a6fff7b1..6d11c083 100644
--- a/sim_disk.h
+++ b/sim_disk.h
@@ -70,6 +70,8 @@ typedef void (*DISK_PCALLBACK)(UNIT *unit, t_stat status);
 
 t_stat sim_disk_attach (UNIT *uptr, const char *cptr, size_t sector_size, size_t xfer_element_size, t_bool dontautosize, 
                         uint32 debugbit, const char *drivetype, uint32 pdp11_tracksize, int completion_delay);
+t_stat sim_disk_attach_ex (UNIT *uptr, const char *cptr, size_t sector_size, size_t xfer_element_size, t_bool dontautosize,
+                           uint32 dbit, const char *dtype, uint32 pdp11tracksize, int completion_delay, const char **drivetypes);
 t_stat sim_disk_detach (UNIT *uptr);
 t_stat sim_disk_attach_help(FILE *st, DEVICE *dptr, UNIT *uptr, int32 flag, const char *cptr);
 t_stat sim_disk_rdsect (UNIT *uptr, t_lba lba, uint8 *buf, t_seccnt *sectsread, t_seccnt sects);