[foxboro] How to recover a workfile (was: ICC to CP disconnect)

Re: How to recover a workfile

This is an oldie, but a goodie. I thought it might be of use.

AJ


It must be the time of year, the topic of how to properly back up a CP
and how to recover from the loss of the hard drive on the hosting AW has
come up several times and I'm getting tired of doing this one at a time.
So, here are my thoughts for all to ponder.

This is really a case where free advice is worth what you pay for it.
Remember, this does not replace the standard company policy of:

   1) SAVE ALL
   2) Failure
   3) INITIALIZE
   4) Reboot
   5) LOAD ALL

However, even the company standard procedure does not address
everything, e.g., #include files. So, be sure you keep those up to date
somewhere off platform.

So, with all of the expected caveats about free advice and standard
documented procedures, read on.

------------------------- Danger starts here
----------------------------

I have the general outline of a procedure, but it is NOT for the faint
of heart. There are at least a few difficulties and probably more. The
ones that I can think of are:

   1) Recovery of Sequence Code Source and Ladder Logic source
      is not going to happen, you must have up to date backups
      of this code. Basically, my advice is, "Make a SAVE ALL
      every time you recompile a Sequence Block or a PLB block."
      Also, if you use #includes you need to back those up, they
      won't be on the SAVE ALL.
   2) Block Order recovery can be awkward. You can use the order
      shown by the CP in the FoxSelect or Select window as the
      master and make the workfile match it - see below for what
      I'm talking about.
   3) dbvu does not like dumping out the parameters of CPs that have
      certain ECBs in them. I'm talking about the -t option (at
      least the last time I tried it on a CP60). This can make life
      tougher.

General words of advice:
   1) Get help from Field Service! I can't stress this enough.
      There are guys who have had the (mis)fortune of doing this
      more than once. You probably have not.
   2) Understand what the relationship is between CSA, work files,
      checkpoint files, CP RAM, and the Sequence Block and Ladder
      Logic source code.
   3) In the future, be dead certain to make SAVE ALLs after all
      changes to Sequence (IND, EXC, DEP) or PLB blocks. This
      preserves your source code. Regular Save Alls will minimize
      the work, but will not eliminate the need for this procedure.
   4) If you use #include statements in your sequence code, you'd
      better back those files up! SAVE ALLs don't preserve them.
   5) Save Alls can be automated using scripts that can be found on
      the Cassandra Web Site. While that will not totally remove the
      need for SAVE ALLs after alterations of Sequence and Ladder
      Logic code, it will help.

Here is the general gist of the procedure.

   1) Setup a duplicate system off line. It should contain at least
      an AW/AP with the latest backup tape for the CP host and a CP
      of the same type with the same letterbug.
   2) Boot the off-line system
   3) Determine which compounds/blocks have been added / deleted
      between the two CPs. You can use a variety of tools to get
      this information.
      a. Workfile content
         i. The print options of the ICC and ICC Driver Task
            can document the workfile
         ii. The refs toolkit - on the Cassandra site - can
            document workfiles
      b. CSA
         i. The CSA tools (see the attached file csa_util.doc)
            can be used to see what CSA thinks is there.
      c. CP's Running Database
         i. /opt/fox/bin/tools/dbvu - can be used to examine a
            checkpoint file and pick out compound and block
            names.
         ii. FoxSelect can be used to determine what the CP
            actually has in it (same info as dbvu)
      d. Block Order - Use Select or FoxSelect to see the order of
         the blocks as known to the CP.
      e. Source Code Files - are a problem because they are on the
         host and not in the CP. There is no way to to ensure that
         you actually have the latest source code for the Sequence
         Blocks and PLB blocks.
   4) Use the off-line system to build a correct CP image. That is,
      one:
      a. That has the correct set of compounds and blocks. This is
         a pain.
      b. That has the right block order
      c. That has up to date Sequence and Ladder Logic blocks
         i. The correct Sequence Code and Ladder Logic files
         ii. The correct #include files.
         iii. Recompiled source
   5) Once you have an up to date CP configuration in the off-line
      machine, you need to move it to the main machine.
      a. Make a backup of the critical files
         i. cd /opt/fox/ciocfg
         ii. tar cvf <cpLbug>.tar <cpLbug> <cmpdName> <cmpdName>
          where <cpLbug> is something like CP0001
          <cmpdName> is the name of a compound in the CP that
          contains Sequence or PLB blocks.
      b. Move the tar file (<cpLbug.tar>) to the on-line host
         and put it in /opt/fox/ciocfg
      c. Extract the files (tar xvf <cpLbug>.tar)
      d. Start the ICC and perform an upload from the CP
   6) Use the CSA utilities to fix the CSA database if necessary.

Other techniques are possible given different starting points. Some of
you may have everything back documented with FoxCAE for example, but
they all boil down to this.

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