Update instructions for reading and writing tapes.

Add information about file formats.  Add information about new KA10,
KL10, and KS10 emulator tape device names.  Add crdir to create
directories.

doc/DUMP-itstar.md

@@ -1,5 +1,27 @@
 # DUMP and itstar
 
+### A note about emulators
+
+ITS runs on many PDP-10 emulators, and they have various names for the
+tape device.  KLH10 calls it `mta0`.  The SIMH based KA10 and KL10
+emulators also call it `mta0`, but the KS10 "pdp10" emulator calls it
+`tu0`, and the KS10 "pdp10-ks" emulator calls it `tua0`.  It's
+important to use the right device name.  The instructions below spell
+out each case explicitly.
+
+### A note about file formats
+
+PDP-10 files store 36 bits per word.  Text files store five characters
+per word, plus one extra bit which may or may not be used.  This
+presents a problem when storing PDP-10 files as a sequence of 8-bit
+bytes, and this has been solved using many different encodings.  The
+itstar program expects files to use the "ITS evacuate" encoding, which
+makes text files look like normal Unix LF line ending files.  If files
+use some other format, it's important to convert them to ITS evacuate
+format before use with itstar.  This can be done with the `cat36`
+program in the `tools/dasm` directory.  For example, to convert from
+CR LF line endings, use `cat36 -Wascii -Xits`.
+
 ### Saving ITS files and extracting them using itstar
 
 - Mount a tape image in the emulator.
@@ -11,11 +33,21 @@
          devmount mta0 files.tape create
          continue
 
-  - For SIMH, type
+  - For SIMH KA10 or KL10, type
+
+         attach mta0 files.tape
+         continue
+
+  - For SIMH KS10 "pdp10", type
 
          attach tu0 files.tape
          continue
 
+  - For SIMH KS10 "pdp10-ks", type
+
+         attach tua0 files.tape
+         continue
+
 - In ITS, type `:dump`.  At the _ prompt, type `dump`.  The `FILE=`
   prompt will accept directory and file names.  `*` can be used as a
   wild card.  Finish with an empty line.  When DUMP has finished
@@ -30,11 +62,21 @@
          devunmount mta0
          continue
 
-  - For SIMH, type
+  - For SIMH KA10 or KL10, type
+
+         detach mta0
+         continue
+
+  - For SIMH KS10 "pdp10", type
 
          detach tu0
          continue
 
+  - For SIMH KS10 "pdp10-ks", type
+
+         detach tua0
+         continue
+
 - In the host, run itstar to extract the files:
 
        itstar -xf files.tape
@@ -58,14 +100,27 @@
          devmount mta0 files.tape
          continue
 
-  - For SIMH, type
+  - For SIMH KA10 or KL10, type
+
+         attach mta0 files.tape
+         continue
+
+  - For SIMH KS10 "pdp10", type
 
          attach tu0 files.tape
          continue
 
-- In ITS, type `:dump`.  At the _ prompt, type `load`.  The `FILE=`
-  prompt will accept file names as above.  Finish with an empty line.
-  If you need to load more files, type `rewind` to make another pass
-  over the tape.  When you're finished, type `quit` to exit.
+  - For SIMH KS10 "pdp10-ks", type
+
+         attach tua0 files.tape
+         continue
+
+- In ITS, type `:dump`.  At the _ prompt, type `load crdir`.  (The
+  `crdir` is to create new directories when necessary and may be
+  omitted if all files go to existing directories.)  The `FILE=`
+  prompt will accept file names as above.  `*` can be used as a wild
+  card; for example `*; * *` to read all files.  Finish with an empty
+  line.  If you need to load more files, type `rewind` to make another
+  pass over the tape.  When you're finished, type `quit` to exit.
 
 - Unmount the tape image as above.