Preventing File Modification
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8 hours 53 minutes
If you have created a file, or if you need to preserve a file, you need to be able to control who can open the file, who can make changes to it, who can delete it. And so on
early operating systems. The art is, for example, DOS or the first few versions of Windows.
They used a file system for formatting, the hard drive that was called fat file allocation table.
This did not have the ability to set permissions on files and folders. As a result, anybody could access anything thatwas on that hard drive. And in other words, there was really no security for your files and folders.
It did have something called the read only attribute, so you could go into the properties of a file and you could check the box to make it read. Only
the problem with that was it wasn't really a way off implementing security, because if anybody wanted to make changes to your file or delete it,
all they had to do was repeat the steps going to the properties of the file and uncheck the read only attribute.
When Microsoft released Windows and T as an operating system and Windows NT is really the ancestor off
the current operating systems, like Wood Knows 10
and Server 2012 and served 2016.
anti, when it was first released, introduced a new file system called NT F s, which stands for new technology file system.
And what this did was it gave you the ability to set permissions on individual files and folders
so you could restrict
who could access them
so you could list users and groups who had access to the file
and what permissions they had.
So you could say, You know, one user can read the file and another user can modify the file on. The third user has full control so they could do everything, including deleting a file
Lennox to has a file system called the X T. And this also supports setting permissions as well.
Let's look at a couple of ways off preventing users from modifying a file. A very simple way of doing this is to go into the properties of the file
Check this box read only,
and then click. Okay,
so now if somebody opens the file
on to make some changes to it
and they try and save the changes.
Windows says. You can't do that
because if you look at this dialog box, what it's saying is save. As
so what is telling me is I have to save it under a different name
so the original will still be intact and
the changes are made would be saved in a new file.
if somebody wants to get around that
all they have to do is right. Click on it,
go to its properties,
and I'm check the box.
So although this is a kind of security, it's a very primitive type of security.
So now let's look at somewhat more sophisticated mechanism for protecting your files,
and this is referred to as NT F s permissions.
So in the properties of a file or folder,
you'll see that there is a security type.
Security tab lists what permissions have been given for this file.
So, for example, because I created the file, I have full control over it. I can do everything to it, including deleting it or modifying it.
Also, the administrators group has been given full control,
but currently nobody else actually has access to the files
to give them access, but to prevent them from maybe making changes to it. I can do this.
I can click at it
unless out a group called everyone
and then for everyone.
I can check the boxes here to indicate what permissions they have.
So, for example, I can say yes. They have the reed permission
now, Do I want them to be able to modify it? Because if I do, I can give them the right permission as well.
But if I don't want them to be able to modify it,
I can uncheck that box.
So this point I have full control so I can do anything I like with the file.
The administrative group. Anyone who is an administrator also has full control,
and everyone else
has only got read access to the files.
The same types of permissions are available for folders as well.
So here's a folder. I can go into its properties,
and it too has a security type.
And this is where you can set up permissions.
So again, I can edit, add and remove from the list, check the appropriate boxes and set up permissions that way.
Now Obviously, NDF s permissions are far more sophisticated than that. Read only check box
and tear fest permissions allow you to have very granular sets of permissions where you can differentiate between different users and groups to say this user or this group can do the following things with this viral folder.
The reason they're called anti infest permissions is because NT f s permissions are only available. If you have formatted your drive with a file system called ante F s,
their formatting and NT f s are beyond the scope of this course. But if you go on to say a plus and that work plus courses,
then we'll get into NT F s permissions in far more detail.
So just to summarize, either you can modify the read only attribute. But the problem with that is, is that anybody can uncheck it
or you can change the India fest permissions on the file or folder in order to control access to it.
So far we have been looking at using the graphical interface primarily with the mouse, and that's how most of us do operate with it.
But it is quite possible to do many, many operations without using the mouse. Because most operating systems have a number or keyboard shortcuts that you can use
in windows. This often involves the control key
in conjunction with other keys. For example, if I hold down the control key plot and plan and press see
control plus C means copy.
If I hold down control and press X, that means cut.
If I hold down control and plus Press V, that means paste
control plus Z means reverse the last operation.
So there are those, but there are actually lots of lots of lots of harm.
Keyboard shortcuts. You can go online and get listings of all the keyboard shortcut, supported by Windows and supported by other operating systems like OSX, Lennox and so on.
There are a number of keyboard shortcuts you could use to work with windows.
Sometimes it's faster to use those than keep moving your hand from the keyboard to the mouths and back again.
You could search online for keyboard shortcuts for Windows
Here, you'll see I've got the keyboard shortcuts for Windows 10 popping up. You can also find keyboard shortcut for earlier operating systems.
Let's have a look at the first few ones listed here.
Now, when you see control
as part of the key combination,
this is referring to the key that are on either side of the space bar on your keyboard.
Possibly one of the most common key combinations is old plus tab.
Every time I press that key combination windows cycle through all open windows, letting me select the window I want to work with.
So I'm gonna do that now
and switch over to this folder.
I'm gonna do it again
and open up. This followed up.
So now you can see two folders, one of which is full of files on the other one is empty.
Something has switched back
to the first folder
and then I'm gonna use the following key combinations.
select everything in the folder
copies at all
or tabs allows me to switch to the empty folder
pastes everything in there.
So I've just copied all those fires from one window to another without touching the maps at all.
Also remember that Control plus Z will reverse the last operation.
What is also interesting is that the same key combinations work within applications as well.
So, for example, here I've got a note pad open on. I could take a bit of text selected copy and paste if and I don't do it.
So I'm gonna press come trouble, eh?
To select all the text
control C to copy it
and then control V to paste it.
And then again controlled Zi
I'm just the move.
If you want to do a cut and paste rather than a copy and paste, you can use control X instead of control. See,
there are also key combinations that used the Windows logo key.
If you look down on your keyboard with, it's a keyboard design for PCs,
you should see between the control and the old turkey. There's a Windows logo key,
so 12 combination that's very useful here is the windows keep plus owl,
and what that does is very quickly locks your workstation.
So, for example, if you're about to go for a coffee break, just hit Windows Key plus l that will lock your work station and then you can come back and walk back in
so you might want to spend a little bit of time looking up thes keyboard shortcuts and also memorizing some of the most common ones. They may well come up in the exam.
You may also want to look up some of the
keyboard shortcuts available in other operating systems, such as, Oh, it's axe on dhe Lennox. So again, you can simply search on the Internet for in this case, I searched for
OS X keyboard shortcuts.
One other use soft keyboard shortcuts that camped here. Particularly mentions in the syllabus for the exam is the print screen key.
If you look down on your keyboard towards the top right hand side next to the F 12 key,
you should see a key marked either print screen or print screw with the vowels missing or print screw or something similar.
So what that will do is capture everything that's on the desktop,
so you can then post paste that into any application that accepts graphic input so I could copy everything that's on the screen and paste it into a
Microsoft paint. Or I could even paste it into programs like Power Point or Microsoft Word. If I need to show what was on the screen at any given time
now, sometimes you don't want to capture the whole screen. Sometimes you just want to capture the active window, the window you're actually interacting with. And that can be done by holding down the altar key on the keyboard,
the old keys next to the space bar
and then pressing the print screen key.
So let's have a look at all of that in action.
Sometimes it's useful to be able to take snapshots off what's on your screen.
There are a couple of keys on your keyboard you can use, and
if you look carefully on your keyboard, if you have one in front of you, you see that's a key over towards the right hand side
at the top near the F 12 key.
There is a print screen key
when you press that
that will capture a copy of everything that's on your desktop.
So let's try that. I'm gonna hit print screen right now
that I'm gonna open up
and paste it
and you'll see it captured everything that was on my dad stop
and it's now saved as an image within paper.
We close that
I could have put this point if I wanted to save it but I'm not going to.
let's look at this.
Sometimes you don't want to capture the whole of your desktop.
We just want to capture what's going on within one particular window.
So here we have a window
and it's a three D drawing program,
and I want to capture the content of just what's in this window.
So for that, the key presses Ault print screen,
So we already found the print screen keys over towards the top right of your keyboard.
The old key is next to the space bar near the bottom of the keyboard.
So what I'm going to do now is hole down the Yorkie
and press print screen.
Now the contents of that window have been captured.
Let's open up paint again
and pay studied.
And so now there's the contents solved. That particular window has been captured