Jay McGavren’s Journal

Or, at least, my attempt at it. The real-world test is this Saturday; I’d be interested in any further advice anyone can offer. I’m trying to balance security with ease of setup. This can of course be adapted to other applications.

• In the Finder, copy the Scratch folder from the disk image to /Users/Shared/ under the Macintosh HD.
• To ensure files can be saved to the Scratch Projects folder (which is the default location for a fresh Scratch install), in Terminal, run “chmod -R ugo+w /Users/Shared/Scratch\ 1.3.1″ (or whatever the Scratch folder path is).
• Enable the Guest account via the Accounts preference pane.
• In the Parental Controls pane, enable parental controls for the guest account.
• Check “Use Simple Finder” (this will make it easier for younger kids to navigate to the app).
• Check “Only allow selected applications”, and ensure all applications are disabled except Safari (for establishing scratch.mit.edu accounts) and Scratch. (If the top-level checkbox has a minus-sign, it means some sub-items are enabled. Click the box until it is empty, then expand the tree view to select individual sub-items.)
• Under the Content tab, select “Allow access to only these websites”, click the plus sign, and add http://scratch.mit.edu/ to the list of allowed sites.

When the machine boots, students should be able to click the Guest account, then select the Shared folder in the Dock to get to the Scratch app. (I don’t know an easy way to add Scratch itself to the Dock under the locked-down Finder; let me know if you do.) They can also open and save Scratch projects within Scratch itself, and they’ll be preserved after logout even though it’s a guest account. Safari access lets them establish an account on scratch.mit.edu so they can upload their projects.

They won’t be able to do much of anything else, though - all apps will be hidden, and almost all paths will be inaccessible from the Finder. (They can still see almost anything from Safari, but next to nothing will be writable.) I’d imagine this is enough to keep most kids out of of distraction and/or trouble, but you can disable Safari and lock the machine down still further if you’re concerned.

Edit: My post on how the class went is here. Summary - I wouldn’t say these efforts were unnecessary, but they definitely weren’t essential. We had the program up and running when kids arrived, and that was all we really needed. Security wasn’t much of a concern in this environment.

Man, was this a pain to find. I’m assuming some proficiency with XML and Quicksilver here; leave a comment if you need more specific directions.

Install the Web Search module from the Quicksilver plugins pane if you haven’t already. Quit Quicksilver. Then edit this file:

~/Library/Caches/Quicksilver/Indexes/QSPresetDocWebSearches.qsindex

Search for:

<string>qss-http://www.google.com/search?hl=en&q=***</string>

And change it to:

<string>qss-http://www.google.com/search?hl=en&q=***&num=100</string>

Be sure you’ve got the “Google Search” entry; there are many similar ones. I originally edited the file while Quicksilver was running and had to quit and reload the catalog several times before I got it to stick. Your mileage may vary.

To test, bring up QS, type “Google Search”, tab twice, type your query, and press Return. Your default browser should load a Google Search with 100 results per page. You can of course make any other tweaks to this or any other search URL that your heart desires.

The OS X port of XScreensaver is simple, stable, and unobtrusive as far as I can tell. Unfortunately you can’t (easily) pipe program output into Phosphor and other textual screen savers, but other than that they’re spectacular.

I did toss out some of the less impressive ones, though. Here’s what I kept installed:

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Set your Search Mode to “Snap to Best”. That’ll make sure your last selected action jumps to the top for a given subject.

Typing “.” (period) gets you free text entry as the subject. Pretty handy in conjunction with “Run Command in a Shell”.

OK, just finished porting my toolbox to OS X. I’ve gotten rid of all those dumb text files and generators, as they were really only needed under Windows.

I ported some stuff to take advantage of my Ruby utilities library, and threw out a lot of cruft. Here’s what made the cut…
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Found a folder in the Quicksilver catalog that was indexed to infinite depth, adding hundreds of (wrong) entries and blocking the correct ones. I can actually use it now that I’ve fixed it.

Not being able to navigate without the mouse was actually stressing me out quite a lot. Feels like I just surfaced for air. Gasp!

I’m astounded - went back to the XP laptop to clean out a worm (the first that’s ever gotten past our firewall that I know of), and found myself trying to use OS X keyboard shortcuts. Years of conditioning to the Microsoft environment, undone in just a couple weeks.

Some old habits do die hard, though - I still find myself holding Caps Lock on the Mac in a futile effort to activate Enso. I need to visit the Enso mailing list and see how stable it is on OS X.

I’m getting fed up with GUI OSes in general, BTW. The Mac keyboard shortcuts, while slightly more sensible, are still totally random at times. I feel like I’m learning Street Fighter special moves or something. And there’s no way in hell I’m using the mouse.

I’m tired of losing the window I want amid the myriad windows onscreen and having no way to find it except command-tilde (or whatever), and the problem is made worse by the multi-monitor setup at work. I’ll sit there hammering on the keyboard, wondering why it’s not responding, only to realize I’ve barfed random text all over the terminal on the other monitor.

I’m starting to understand the curmudgeons who refuse to leave Emacs all day, I really am.