diff --git a/jlibrary/addons/data/jmf/jmf.ijs b/jlibrary/addons/data/jmf/jmf.ijs
index 46ba1c392..0f1684819 100644
--- a/jlibrary/addons/data/jmf/jmf.ijs
+++ b/jlibrary/addons/data/jmf/jmf.ijs
@@ -28,7 +28,15 @@ share name;sharename[;mt] - share 'sharename' as name
 
 MAPNAME,MAPFN,... showmap col indexes 
 )
-memhad_z_=: [: {: [: memr 0 2 4 ,~ (15!:6)@<
+3 : 0''
+try.
+ 15!:12 <'a' [ a=. i.5
+ memhad_z_=: (15!:12)@<
+catch.
+ memhad_z_=: [: {: [: memr 0 2 4 ,~ (15!:6)@<
+end.
+EMPTY
+)
 memdad_z_=: 15!:14@<
 
 0 : 0
diff --git a/jlibrary/addons/data/jmf/manifest.ijs b/jlibrary/addons/data/jmf/manifest.ijs
index f93e3da08..130b91d04 100644
--- a/jlibrary/addons/data/jmf/manifest.ijs
+++ b/jlibrary/addons/data/jmf/manifest.ijs
@@ -6,7 +6,7 @@ DESCRIPTION=: 0 : 0
 J Memory Mapped File
 )
 
-VERSION=: '1.0.43'
+VERSION=: '1.0.44'
 
 RELEASE=: ''
 
diff --git a/jlibrary/addons/data/jmf/test/testjmf.ijs b/jlibrary/addons/data/jmf/test/testjmf.ijs
index 46dde97d1..cbd503bd6 100644
--- a/jlibrary/addons/data/jmf/test/testjmf.ijs
+++ b/jlibrary/addons/data/jmf/test/testjmf.ijs
@@ -44,18 +44,18 @@ NB. test jmf file with 0/1/2 map types
 map_jmf_ 'abc';F;'';MTRW_jmf_ NB. 0 maptype
 assert 'def'-:abc
 abc=: 'ghi'
-m=. mappings
+m=. mappings_jmf_
 remap_jmf_'abc'
-assert m-:mappings
+assert m-:mappings_jmf_
 unmap_jmf_'abc'
 
 map_jmf_ 'abc';F;'';MTRO_jmf_ NB. RO maptype
 assert 'ghi'-:abc
 try. abc=: 'jkl' catch. end.
 assert 'ghi'-:abc
-m=. mappings
+m=. mappings_jmf_
 remap_jmf_'abc'
-assert m-:mappings
+assert m-:mappings_jmf_
 unmap_jmf_'abc'
 
 map_jmf_ 'abc';F;'';MTCW_jmf_ NB. COW (copy on write) maptype
@@ -65,9 +65,9 @@ assert abc-:'jkl'
 unmap_jmf_'abc'
 map_jmf_ 'abc';F;'';MTRO_jmf_
 assert 'ghi'-:abc NB. verify =: did not change file
-m=. mappings
+m=. mappings_jmf_
 remap_jmf_'abc'
-assert m-:mappings
+assert m-:mappings_jmf_
 unmap_jmf_'abc'
 
 NB. test nonjmf file with 0/1/2 maptypes
@@ -80,18 +80,18 @@ abc=: '6789'
 unmap_jmf_'abc'
 JCHAR map_jmf_ 'abc';F;'';0
 assert '6789'-:abc
-m=. mappings
+m=. mappings_jmf_
 remap_jmf_'abc'
-assert m-:mappings
+assert m-:mappings_jmf_
 unmap_jmf_'abc'
 
 JCHAR map_jmf_ 'abc';F;'';1 NB. RO
 assert '6789'-:abc
 try. abc=: '9999' catch. end.
 assert '6789'-:abc
-m=. mappings
+m=. mappings_jmf_
 remap_jmf_'abc'
-assert m-:mappings
+assert m-:mappings_jmf_
 unmap_jmf_'abc'
 
 JCHAR map_jmf_ 'abc';F;'';2 NB. COW (copy on write) maptype
@@ -101,9 +101,9 @@ assert abc-:'jkl'
 unmap_jmf_'abc'
 JCHAR map_jmf_ 'abc';F;'';0
 assert '6789'-:abc NB. verify =: did not change file
-m=. mappings
+m=. mappings_jmf_
 remap_jmf_'abc'
-assert m-:mappings
+assert m-:mappings_jmf_
 unmap_jmf_'abc'
 echo 'testmaptype end'
 i.0 0
diff --git a/jlibrary/system/main/stdlib.ijs b/jlibrary/system/main/stdlib.ijs
index 79053b6bf..d080c4e7f 100644
--- a/jlibrary/system/main/stdlib.ijs
+++ b/jlibrary/system/main/stdlib.ijs
@@ -531,7 +531,9 @@ cder=: 15!:10
 cderx=: 15!:11
 symget=: 15!:6
 symset=: 15!:7
+symdad=: 15!:14
 symdat=: 15!:14
+symhad=: 15!:12
 cdcb=: 15!:13
 JB01=: 1
 JCHAR=: 2