diff --git a/sim_disk.c b/sim_disk.c
index 5b7751f5..d27e767c 100644
--- a/sim_disk.c
+++ b/sim_disk.c
@@ -867,6 +867,24 @@ switch (DK_GET_FMT (uptr)) {                            /* case on format */
     }
 }
 
+t_stat sim_disk_erase (UNIT *uptr)
+{
+struct disk_context *ctx = (struct disk_context *)uptr->disk_ctx;
+uint8 *buf;
+t_lba lba;
+
+if (uptr->flags & UNIT_ATT)
+    return SCPE_UNATT;
+
+buf = (uint8 *)calloc (1, ctx->storage_sector_size);
+if (buf == NULL)
+    return SCPE_MEM;
+for (lba = 0; lba < ctx->container_size / ctx->sector_size; lba++)
+    sim_disk_wrsect (uptr, lba, buf, NULL, 1);          /* write sector */
+free (buf);
+return SCPE_OK;
+}
+
 /*
    This routine is called when the simulator stops and any time
    the asynch mode is changed (enabled or disabled)
diff --git a/sim_disk.h b/sim_disk.h
index 738a5804..27efde02 100644
--- a/sim_disk.h
+++ b/sim_disk.h
@@ -69,15 +69,16 @@ 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 dontchangecapac, 
-                        uint32 debugbit, 
-                        const char *drivetype, 
-                        uint32 pdp11_tracksize, 
-                        int completion_delay);
+                        size_t memory_sector_size,  /* memory footprint of sector data */
+                        size_t xfer_element_size, 
+                        t_bool dontchangecapac,     /* if false just change uptr->capac as needed */
+                        uint32 debugbit,            /* debug bit */
+                        const char *drivetype,      /* drive type */
+                        uint32 pdp11_tracksize,     /* BAD144 track */
+                        int completion_delay);      /* Minimum Delay for asynch I/O completion */
 t_stat sim_disk_attach_ex (UNIT *uptr, 
                            const char *cptr, 
-                           size_t sector_size, 
+                           size_t memory_sector_size,   /* memory footprint of sector data */
                            size_t xfer_element_size, 
                            t_bool dontchangecapac,      /* if false just change uptr->capac as needed */
                            uint32 dbit,                 /* debug bit */
@@ -93,6 +94,7 @@ t_stat sim_disk_rdsect_a (UNIT *uptr, t_lba lba, uint8 *buf, t_seccnt *sectsread
 t_stat sim_disk_wrsect (UNIT *uptr, t_lba lba, uint8 *buf, t_seccnt *sectswritten, t_seccnt sects);
 t_stat sim_disk_wrsect_a (UNIT *uptr, t_lba lba, uint8 *buf, t_seccnt *sectswritten, t_seccnt sects, DISK_PCALLBACK callback);
 t_stat sim_disk_unload (UNIT *uptr);
+t_stat sim_disk_erase (UNIT *uptr);
 t_stat sim_disk_set_fmt (UNIT *uptr, int32 val, CONST char *cptr, void *desc);
 t_stat sim_disk_show_fmt (FILE *st, UNIT *uptr, int32 val, CONST void *desc);
 t_stat sim_disk_set_capac (UNIT *uptr, int32 val, CONST char *cptr, void *desc);