Writing Basic Procedures

Today, we spent our time with a chap called Jon Slater who gave us a run down of SCL (System Control Language). He went into a lot of detail about all the different commands that you can use within OpenVME and what their functions are, giving examples each time which I found very helpful. He also shown us that you are able to create your own files; create_file is a temporary file and doesn’t add anything into it and once you end your block it removes itself. Input file is a permanent file and it allows you to add content.

There is two types of users; Multi-Accessing Computer (MAC) and this requires a particular set of credentials for the user, you are allowed to write commands in this user and each user can only see the files, etc. in that specific user unless  other users specifically give them access to their files. However, lots of people can log into a particular user and they would all see any files in that user. The TP (Transaction Processing) is where 100’s or 1000’s of people share the same code and the TP have pre-defined functions. For example a mobile able, you can only do what the app lets you, or if you are topping up your mobile phone and it says “Press 1 if using a top up voucher”. You get the idea, I hope. The Transaction Processing user is usually for customers using OpenVME, checking their customer details, purchases etc.

We learnt that there is 3 different types of storing files. The first one is a free file which is just on its on and can be easily found. The second is a group of files gathered and grouped together. The third and final one is a library, and all the files in the library (LB or LIB) are the same type of files, in an orderly fashion just like a real library. The files that are in libraries can be executable if the library if the correct type but any library. There is also a thing called ‘allocation’ which just allocates all the files onto a disc somewhere so they are stored safely.

Another thing we touched on was variables; integers (whole numbers), strings such “Ben” “Jordan” “Jon” , another one was BOOL which is just a yes or no function or in this case “True” and “False”, the final one was a Super-String, this would be similar to an ordinary string but set out like “Ben”&”Jordan”&”Jon”. Once Jon shown us all the basic commands he then shown us how to write a basic procedure and then went into an advanced procedure, showing us the differences as well as the similarities. Even though its more advanced, some of the basic commands are used within it. He then gave us a taster of error trapping, which traps any errors you have in your code and starts a procedure that instead of assigning the file it creates it instead.

In all honestly, I don’t understand every detail but I do have a fair understanding of OpenVME now and what goes into creating procedures and so forth. I appreciate the lesson we got from Jon Slater and look forward to trying some stuff of my own.