In the last issue of MNJ we took a more technical look at just what a resource is, what they do and how they are used. I also promised that we would take a closer look at the resources in the System file and do some of our own customization. Before we jump in with both feet an important note: Make a copy of your System file and do your editing on the copy! Even though it is possible to edit the original System file while your mac is running, the consequences of messing up should be obvious. Briefly, here's the procedure you should use.
1) Make a duplicate of the System file.
2) Do your editing on the duplicate.
3) When you're done, rename the original System file and move it out of the System folder.
4) Rename your edited System file and move it into the System folder.
5) Restart.
6) Computer won't boot? Grab that tools disk and swap things around.
7) Computer works? Great! But remember that you're doing brain surgery on your mac and if it starts doing strange things, your first attempt to remedy the problem is replace the System file with the original.
Ok, enough chat, here we go. Do the steps 1 and 2 above and then open the System file with ResEdit. Wow! There's quite a few resources here! Yep, the one we'll mess with this time is called 'ICON'. You'll probably have to scroll around to find it. Go ahead and open it, either by clicking on it once and using open from the file menu, or by double-clicking on it. Now some of these should look familiar, as resources 0, 1 and 2 are the most frequently used warning symbols on the mac. Go ahead and double-click on the 1 resource (the talking head).
 
Whoops! What's this message all about? Apple figures that certain resources aren't going to be modified, so they compress them to make your system file smaller. When we open, edit and then save them, they won't be saved compressed, so your system file will be a little larger, but not enough to really make much difference. (BTW, your mac automatically uncompresses these files when it needs to use them anyway so you'll actually speed up your mac at the cost of disk space.) Go ahead and answer yes to that dialog box and we'll continue on.
  
Once you open the resource, you'll see that what you've got is a very simple graphic editor; pen, eraser, box, circle, line, etc. Go ahead, edit to your hearts delight and when you're done, come on back.
Hint: If you've accidently made changes to a resource and you need to undo them, you don't have to quit and say no to saving the changes. Up in the Resource menu is an option 'Revert 'whatever' resource, and it does just what it says. Cool huh?
Like what you've got? Good. Quit ResEdit and go ahead and save the changes, then do steps 3 - 7 above and you're done! This is one of the safest changes you can make to your System file as you're really not changing much, just the pictures. In fact, you could have made these changes on the original System file while your computer was running, but this is definitely not for the faint of heart. Blow it and you'll really blow it!
Go ahead and do some more looking around, next issue we'll take a look at changing your cursor. Had enough of the watch? We'll fix that. Until then, good browsing!
