Oh, Yes! A long story, but if you remember IBM JCL, you might find the story interesting.
I started as a Cobol programmer trainee in a very small shop of only 4 programmers, of which one was me and another one the supervisor. We coded our own JCL and perform the testing of our own programs. ie: We were the computer operator.
I was new and I was given a location for my test file on disk pack WS03. In JCL, if I remember correctly, the first time you wrote to the disk file you coded “Disp=new”. After the first time you wrote to the file, you then coded your JCl “Disp=shr”
Like I said earlier, we operator the computer when we tested our programs. I walk into the computer room, mount the disk pack WS03 and tested my program for the first time creating the new file.
Later that day, the regular computer operator start the billing process that used 9 disk packs label WS01 thru WS09. When the program got to disk pack WS03 the operating system reported an I/O error that could not be by passed and the billing program abended.
Having the billing process abending cause a big stir in the office and the programmers (including me) came into the computer room. I mention that I had used WS03 that afternoon.
WHAT!! Why did you do that! I replied I was told by my supervisor to use WS03.
Well, the billing disks were label in “Blue” WS01 thru WS09. The disk pack I was suppose to use was coded in “Green” WS03. I was not told to use the “Green” labeled disk pack so neither I nor the supervisor got into trouble.
What was surprising was that in JCL, you could also code “Expire=99/365” for your file. If the operating system try to write over an area coded with “99/365” the operator would get a warning and he then could let the program proceed or cancel the option that was trying to write over the protected area.
The billing file did not have “Expire” coded, so there was no protection for the billing file. I got no warning that I was about to write into an area that contained the billing master file. The JCL for the billing process was soon changed to include “Expire=99/365”.