diff --git a/_Docs/LIBBLKDEV.md b/_Docs/LIBBLKDEV.md
new file mode 100644
index 00000000..a722ca0e
--- /dev/null
+++ b/_Docs/LIBBLKDEV.md
@@ -0,0 +1,51 @@
+*** Auto generated by docgen.cmd ***  
+
+#GetProDOSCatSize
++ Compute space needed for ProDOS Catalog
+
+##In :
++ PUSHW = DevSize (in 512b blocks)
+
+##Out : 
++ X=BlockCount (max 22)
++ A=PageCount  (max 44)
+BuildProDOSCat
+
+##In :
++ PUSHW = DevSize (in 512b blocks)
++ PUSHW = VolName (PSTR)
++ PUSHW = DstBuf (Zero filled)
+ + Blk0 : ProDOS.BootBlk
+ + Blk1 : SOS.BootBlk
+ + Blk2,3,4,5 : Volume Directory
+ + Blk6....   : Volume Bitmap (4096/Blk)
+ + max devSize = 65535 ->  max 16 Bitmap Blk
+ + absolute MAX DstBuf size=
+ + 7 for Disk II(280blk),3.5(1600),3.5HD(2880)
+ + 22 for 32mb Hardisk...
+
+#TrkW16s
+Write a track (16 sectors)
+
+##In:
++ PUSHW = Ptr to 16*256 buffer
++ PUSHB = TrackNum * 4	: 0->140+	
++ PUSHB = DSSS0000
+
+##Out:
++ CC : success
++ CS : A = Error
+ +     A=0, currently starting/seeking...
+
+#TrkWNIB
+Write a track (NIBBLE)
+
+##In:
++ PUSHW = Ptr to NIBBLE buffer (0 ended)
++ PUSHB = TrackNum * 4	: 0->140+	
++ PUSHB = DSSS0000
+
+##Out:
++ CC : success
++ CS : A = Error
+ +     A=0, currently starting/seeking...