Subject: Proper care and feeding of source code

(This message is being sent to all CPSC 102 Sec 1 students )

One unfortunate student kept getting unresolved references
to camera_init(), camera_getdir(), etc and so he sent me
a tar file.  I found (as described below) that he had
inadvertently destroyed his own camera.c file:

---------------------------------------------------------

If you cat or try to edit the camera.c that you sent me
you will see that it is empty.

The 0 below means the file has size 0.
/home/westall/sp ==> ls -l camera.c
-rw------- 1 westall ecryptfs 0 Jan 24 13:55 camera.c
/home/westall/sp ==>

There are various ways you can do this to yourself including

(1) running the tar command improperly
        tar cvf *
    will destroy the first file in your directory.
(2) running gcc incorrectly
       gcc -o camtest.c camtest.c camera.c
    will destroy camtest.c

There is no way to fully protect oneself from making these
careless mistakes -- I still do it to myself occasionally.

So it is strongly recommended that you regularly create
backups or new versions of whatever you are working
on so that when it does happen,  you will lose less work.

Here is how I did it in building my own system:
Each time I make a little progress I want to be
sure to preserve,  I make a new directory (mwray1, mwray2,
etc) and copy the stuff forward before I start working
on in again --- that way if I really screw it up I can
always go back to the last generation.

mwray1   mwray16         mwray20         mwray8            mwraypp17         mwraypp5
mwray10  mwray17         mwray20.tar.gz  mwray9            mwraypp18         mwraypp6
mwray11  mwray18         mwray3          mwraypp1          mwraypp2          mwraypp7
mwray12  mwray18.tar.gz  mwray4          mwraypp15         mwraypp20         mwraypp8
mwray13  mwray19         mwray5          mwraypp15.tar.gz  mwraypp20.tar.gz  mwraypp8.tar.gz
mwray14  mwray19.tar.gz  mwray6          mwraypp16         mwraypp3          mwraypp9
mwray15  mwray2          mwray7          mwraypp16.tar.gz  mwraypp4          mwraypp9.tar.gz

You might use a strategy like naming versions of assignment sp1
sp1a, sp1b, sp1c etc.

Although to my knowledge we have never lost data due to
a file server failure its also a good idea to protect yourself
against that eventuality by periodically emailiing a tarball
to yourself.

It is SUPER COMMON to have laptop disks fail.  So if you are
developing ANYTHING on your personal system, from programs to
term papers, you should backup to a file server (or USB memory
key) AT LEAST ONCE A DAY!!