Ask TUAW: limiting net access, encrypted external volumes, pdf management and more

One again we've got an overload of Ask TUAW questions from last week's episode! So in this round we'll be treating questions about limiting net access, encrypting external volumes, airport problems, installing OS X from a DMG, pdf management and more.

As always your suggestions are most welcome, and questions for next week should be left in the comments. And now on to the questions!

thethirdmoose asks

I have a quick, but important question: Is it possible to close off all internet access except for one application, and make it so Firefox doesn't load and display pictures? The reason for this is that I want to use my phone for data, but it has a slow (CDMA2000) connection, and a 10 MB/week download cap. Do you know how I could do this? Thanks

Probably the easiest way to block all applications except Firefox from accessing the internet is with something like Little Snitch ($24.95) from Objective Development. You could set up rules that block everything else but Firefox.

Getting Firefox not to display graphics just requires you to uncheck the "Load imaged automatically" checkbox in the Content tab of Firefox's preferences.

Greg asks

Can I password-protect an external HDD? I have an Ex-HDD (a WD MyBook) that I use for backups and general file-storage with my MacBook Pro, and I'd like a way to secure that HDD so that if someone were to plug it into their computer, they would not be able to access the files in it without a password.

A free way to do this would be probably be to create a Disk Image on the external hard drive, with the Disk Utility application. Just create a new Image on the external drive and be sure to set the encryption. Of course you'll have to mount that image separately from the external drive (just by double-clicking on it), but if you keep all your data on that image, then you should have about what you want.

If you're willing to drop a little change, however, Knox ($29.95) would probably be the easiest way to accomplish this as it can "reformat USB sticks and external drives as encrypted Knox vaults."

Luigi193 asks

Whenever I mount my 24" iMac's drive on my macbook, and the iMac falls asleep, my Macbook's apps all stop working and all the programs I open or try to close just bounce on the dock. This goes on for about 2 minutes. It used to just try to connect and then say it couldn't find it and that was the end. But now it goes through this spaz out process. I know its trying to find the drive but its not there (because its asleep) but I am wondering why it is freaking out like this. I also would like to know, besides never letting it go to sleep, or using WakeonLAN to wake it every 15 minutes, if there is a way to make OS X not try to look up the drive when I am not accessing it? It gets annoying when I step away for a few minutes and my computer is frozen (temporarily)...any thing would help.

Unfortunately, as we've mentioned before this is a known problem with OS X and network mounts. The best solution is just not to allow the iMac to go to sleep.

Johnny asks

I just picked up a 1.5TB Maxtor One Touch III. It has two 750GB hard drives in it that are RAID 0 configured. You can also configure it to RAID 1 for added data security. What I'd really like to do is have it function like two separate 750GB drives. That way, I can use ChronoSync to mirror them every night or so, simply because past data loss has always been a result of my own late night delirium, rather than hardware failure. Does anyone know how to hack this particular solution?

What you want is a JBOD (just a bunch of disks) configuration. Unfortunately, looking at the specs and data sheet for this drive this does not seem to be supported by the interface within this drive so I think you're out of luck. If you can still return it, you might want to look for a different drive that supports JBOD.

Update: there is some confusion about what 'JBOD' means. If you consult Wikipedia you'll find that the term has two different uses. I am using it in the second way, not as the concatenation of independent disks into one logical volume but in the sense of a single enclosure what nonetheless independently mounts its internal drives separately in the OS. ("Some RAID controllers use JBOD to refer to configuring drives without RAID features. Each drive shows up separately in the OS. This JBOD is not the same as concatenation.")

Niles asks

I have a 160GB External HDD, and I want to boot a Leopard beta from it. How would I go about doing that? Someone told me Carbon Copy Cloner, but no luck. Just in case you're wondering the OS is compressed in a DMG...

I'm going to just assume you have Leopard legitimately. If that's the case, partition the external hard drive into an install partition (e.g. 10GB) and the rest using Disk Utility. Now restore the DMG to the Install Partition (again using Disk Utility). Reboot the Mac holding down the option key and select the Install Partition. That should start the Leopard installer and allow you to install it on the other partition of the external drive. I found some more detailed instructions here.

Yendi asks

I recently got an Airport Extreme (and love it!). However, whenever my MBP wakes from sleep, it has dropped the wireless connection. In such a case, I have to select my ssid from the airport menulet. Didn't happen with my old wireless router (Linksys WRT-54G). My iMac does something similar, but sometimes drops the connection when the screensaver comes on. How do I keep the connection there?

This is unfortunately a sometimes touchy thing. In the Network Preferences select the Airport interface and then go to the Airport tab. Make sure your SSID is at the top of the "Preferred Networks" list. If that doesn't work you can try changing the "By default, join:" setting to Automatic. I know that's not a very satisfactory answer, but this is one of those little issues that seems to crop up from time to time and there's often no clear solution.

Catulo asks

Going to get a new iMac on Oct/01, do you guys think APPLE is going to charge me an extra US$123.00 more by the end of the month when LEOPARD comes out on the market? Should I hold 'til leopard comes out? Just can't wait to put my hands on the new iMac, mine is from 2002 G4, I mean it's OLD! Please I need you help.

If Leopard were to drop within Apple's 14 day return period from the time you bought your Mac, you might have a shot at talking a store manager into giving you some sort of consideration, but I definitely would not count on it. Apple is not like the PC makers; they will not sell you a computer now with a free OS upgrade later. So you should not expect to get one. If I were you, I would just wait to buy the iMac after Leopard ships. In fact, I'm doing exactly that since I too want to get an iMac with Leopard.

Klemens asks

I'm a (German) Business Student, and for our classes we are given PDFs. These are identical to the professor's presentations. The "traditional" way is to print them and write your notes on the paper. Is there an application which allows to make comments to PDFs (page per page), in an easy way, on the fly (no clicking, dragging boxes - gotta be fast). I know that Preview allows me to make notes to PDFs, but when you save the PDF you can't make them disappear anymore.. Ultimatively, is there an App that does this and also provides iLife-like PDF-Organisation? Like a library, which stores the original documents and the comments seperately?

I myself have wanted more or less exactly what you describe, but unfortunately no one solution exists to do this on the Mac to my knowledge. Perhaps the closest thing to the library organizer is Papers (€29) or Yep ($34), but neither one has extensive commenting features. For that I'd probably point you to the free open source application Skim, though it lacks the library management features. So basically I don't think there's any one application that will do exactly what you want, but you may be able to cobble together a workflow that will suit your needs.