Files and folders

1. Introduction

This document describes the file system on the MS-Windows computers in the computer labs.

Much of it will also apply to other MS-Windows computers you have access to. However the system and the user interface for MS-windows changes a lot between different releases of MS-Windows, so Your Milage May Vary (YMMV).

Some of what is said here applies to other systems too, the principal ones being MacOS and Linux.

Some of what is said here will surely be known to most of you. It is repeated simply to make sure nothing important has been left out. I imagine just about everyone (even people with a reasonable amount of experience of computers) will find something useful here.

Important: a lot of the instructions here ask you to type particular things or give something a particular name. If you do not type what is asked exactly (i.e. you get a single character wrong) it is very likely not to work at all. Computing is all about being 100% accurate. If that's a problem for you then it is something you will have to learn. The same goes for mathematics!

2. Disks or drives

Information is stored on the computer on "disks" or "drives", usually hard discs which are spinning pieces of magnetised metal, but there are also flash drives, solid state disks, and other media that to the computer appear and behave exactly like disks or drives, so that is what we call them even though physically they look quite different. The spellings "disc" and "disk" are equivalent but the first of these is no long common, unfortunately. Disks which are pieces of metal driven by motors will also become uncommon in the next few years, but the words "disk" and "drive" will continue.

For the rest of this, "disks" and "drives" are taken to be synonymous. Both words are used at times and you need to be aware of both.

MS-Windows labels disks or drives with a single letter followed by a colon. Thus C: is usually the main disk or drive on the system, and E: is often your flash drive. It is up to you to work out and remember which is which, and there is no guarantee whatsoever that the F: drive on one computer corresponds to the F: drive on another computer. (This is a serious disadvantage of MS-Windows. Mac and Linux systems do things differently.)

In the computer labs here in Birmingham you should not save information to the main disks on the computer you are sitting at. That is because the next time you do your work you will most likely be at a different computer and will not be able to access your data. Three sensible options are:

carry a USB flash drive with you and save data on that;
save your data on the special networked drive associated with your computer account (here in Birmingham, for students, this drive is usually called U:);
do both of the above.

There are always pros and cons.

A flash drive has the advantage that it will work even when there is a problem with the network. It has the disadvantage that it is easy to leave behind or lose.
The networked drive is great when it works but not so good when you want to take files home.
Having two copies of a file is great for security (safer, less likely to lose files) but bad if you get confused and edit two versions of the same file in different ways and then you "forget" which is the "correct" version.

3. Folders or directories

Data is stored in drives using files and organised into folders. A folder (also called a directory, the words are synonymous in this context, and both are used - you need to be comfortable with both) collects together files and folders which all have a related purpose. Files contain the actual characters, numbers or other data you want to store.

It is tempting not to bother with folders, as "the files are more important", but folders are useful for organising things and reducing clutter. Equally important, folders help you find important files after a few months or or years.

Recommendation: always create folders for new tasks, and try to give your folders a logical hierarchical structure.

In MS-Windows you can view files and folders with the Windows Explorer. (A similar program, usually called a file manager, is available on other systems.)

Do this: Start Windows Explorer by doing any of the following.

Press the key combination Windows-E.
There may be a folder icon on your screen with your name that you can double click.
Press the start button and search for "explorer.exe" and click it.
Press the start button and click "This PC".

You will see lots of files and folders, most of which you can ignore and leave well alone. (If you don't know what something is or does you should leave it alone.)

Do this:

Identify the drive letter for your networked "home folder". This is often called U: on Birmingham University systems. If you look at this in the file explorer it should have your user name (in the form ABC123) attached, and probably the letters "U:" nearby. Click it and have a look at it.
If you have a USB drive attached, identify where this is and look at it in Windows Explorer.

You can do your work and save your files in this "home folder" or on the USB drive. I will refer to this drive as "U:" throughout the rest of this text, but you should replace this with the actual drive letter you are using.

Do this: create a folder inside your main networked folder called "FirstYear". Make another one for "SecondYear", and one for "ThirdYear".

To do this, right click inside the folder and select "New > Folder" from the menu that appears. A folder is created with a highlighted name and you can type a replacement name, followed by the enter key or a mouse click elsewhere in the window.

If you are a first year student, do all your first year work in sub-folders of the "FirstYear" folder. Do something similar for "SecondYear" (etc.) next year. This hierarchical structure will help you find files you need in a hurry later on.

NOTE: through out these pages where you see an instruction with some word or words in double quotes, do not type the outside double quotes. So the name of the "FirstYear" is typed FirstYear . If there are quotes that you must type they will also be present on the inside. So if you are asked to type "print "hello"" then you strip the outside quotes and type the characters print "hello" with one set of quotes.

Quotes and spaces always cause confusion and are in fact a major source of bugs and computer problems too.

Recommendation: do not use spaces or special characters in file names or folder names.

Characters such as letters, digits, and a small number of special characters (e.g. - _ ~ $) are usually OK but the space character and , . / \ " ' ( ) [ ] ; " often have special meanings and will cause some software to run incorrectly.

Unfortunately, when software runs incorrectly, it may not do so in any predictably understandable way, and it might even look like it is working when it isn't. Sometimes this is because of a "bug" in the program, sometimes it is because the program wasn't designed to work with such file names. Or possibly the program may even be completely correct, but you didn't know that the special characters are designed to be used as a way of getting it to do something strange or clever. The computer in front of you probably has hundreds or thousands of bugs, and it certainly has hundreds or thousands of ways to do something "advanced", so be sensible! Whatever the reason, strange filenames do frequently cause problems and it is not worth the risk.

Reason: inside the computer there are "commands". Suppose you want to run a program called "myprog" on files "my file" and "your data". (The quotes are not part of the filenames, but the spaces are.) You might do this by clicking the mouse a few times to do this, but internally the computer works by generating and runnning a command, in this case the command "myprog my file your data". Now it is difficult to see where each filename starts and ends. If there are also files called "my" "your" "data" and "file" it is very very likely to do the wrong thing. As mentioned this is a very common problem. Every year I see many students which get in a serious muddle because of this.

Exercise: Decide or guess what the first name, middle name, and surname is, for the composer "Ralph Vaughan Williams". What information did you need to do this? Check your answer on the internet. Now imagine how a computer program might decide the answer to this question. Are the spaces helpful or a problem? Would you rely on the spaces to make such a decision in all such cases? or is background knowledge that computers can't be expected to have (such as "Ralph, Vaughan, and William are common boys' first names, but Williams (with an s) is usually a surname") important?

Exercise: Do the same, but split the following names (a list of one, two or more files), determining what the names of the folder and sub folder (if any) the files are in, and what the files' names are:

Documents\my file\calculus work text first year stuff\programming

How might the computer decide?

4. Files, applications and data

File names look like folder names, and the same rules apply. (So be sensible do not use spaces or special characters.) File names in MS-Windows also have an "extension" which is usully a dot followed by three letters. (Sometimes there are more than three.) The "extension" tells the system what type of file it is and what sort of things you might expect it to do with the file. It also tells the system what icon to associate with the file. It's a really important part of the name, but unfortunately many MS-Windows systems do not display it properly. This is something that varies between systems and set-ups, and if you are "administrator" you may be able to make system-wide settings. You may or may not have this option on university computers. However, if you are told to upload a PDF file for an assignment it is this extension that matters.

If you cannot see the extension or "type" of a file then you can find out what it is by right clicking the file in Windows Explorer and selecting "properties" from the menu.

Try this now for some of the files you can see.

File names ending with the extension ".exe" are typically applications (or "apps") or alternatively can be regarded as "commands" to the system. We'll see examples later.

MS-Windows also likes to call files "documents". This is just another synonym that has been introduced to "simplify" things for you. (In practice, it just adds another possible source of confusion.)

Most of the work in this section of notes will involve text files (or text documents) which often have the extension ".txt". Sometimes the text files we use will have different extensions. These are the simplest and most useful kind of files. They simply contain a sequence of typewriter characters and nothing else, no special formatting, and nothing else.

Do this:

Create a text file in your "FirstYear" folder called "readme.txt". Do this by right-clicking empty space in the folder and select "new > Text Document" from the menu. Rename the file created to the required name.
Double click the new file to open it in notepad. Type a nice message, save it and close Notepad.
Re-open it to check your message is still there.
Go to your USB flash drive and create a file called "IfFoundReturnTo.txt". Open the file in notepad and give details of how to return the usb drive to you if it is lost and someone else finds it. Don't forget to say "thank you" as well :)

One of the most common tasks in computing is editing (i.e. writing or modifying) text files. MS-Windows provides you with the "notepad" application for this, but this very primitive and very basic. The computer labs in Birmingham have "notepad++" which is a lot better. If you have a MS-Windows computer of your own you should install a text editor of your choice because it will be useful.

Create a text file called "test.lua" and edit it with notepad++. (Note: depending on the way your MS-Windows computer is set up, this can be tricky. Read on in this section for more details.)
One way to get started is to create a text file as shown earlier and then rename it. Try this now. You should have no difficulties making a blank file called "test.lua". If MS-Windows issues a warning that's OK.
Look at it using right-click > properties in File Explorer. You might find the file name really is "test.lua". But another possibility is that it is really called "test.lua.txt". It is claimed that this behaviour by MS-Windows (lying about the file name) is actually helpful. Whether you like this sort of help is up to you!
If you really want to be able to see and modify file extensions using MS-Windows there is a setting in "File Explorer Options" under control panel. (Note: these options are available elsewhere on other versions of MS-Windows.) Unclick the option that says "Hide file extensions for registered filetypes".
If you only want to work with ".lua" files the simplest plan is to use notepad++. Right click the file and select "edit with notepad++" and then use File > Save as to save as a .lua source file.
However you managed all of this, right clicking a file and selecting "edit with notepad++" seems to be preferable to using the default "notepad" application. Put some massage in the file, close and re-open.

notepad++ is quite sophisticated and has a lot of settings. This is not the place to go into them all. If you are the sort of person that likes to find out about such things then please do so. If you have a different preferred text editor then find out about that instead.

In the next section we will look at some apps and how you can get apps to "run" text files. You can look in the "This page" menu at the top and select "next" or go back to the contents.