diff --git a/sys/dev/disk/nata/ata-disk.c b/sys/dev/disk/nata/ata-disk.c
--- a/sys/dev/disk/nata/ata-disk.c
+++ b/sys/dev/disk/nata/ata-disk.c
@@ -144,7 +144,8 @@
 
     info.d_secpertrack = adp->sectors;		/* optional */
     info.d_nheads = adp->heads;
-    info.d_ncylinders = adp->total_secs/(adp->heads*adp->sectors);
+    info.d_ncylinders = (adp->heads && adp->sectors) ?
+		    adp->total_secs/(adp->heads*adp->sectors) : 0;
     info.d_secpercyl = adp->sectors * adp->heads;
     info.d_serialno = atadev->param.serial;