In this episode of Ask TUAW we'll be looking at questions about syncing between a Mac portable and a Mac desktop (backing up and iTunes playlists), battery comparisons between manufacturers, sharing files from a NAS to an Apple TV, subtitles on an iPhone and much more.

As always your suggestions are most welcome, and questions for next week should be left in the comments. When asking a question please include which machine you're running and which version of OS X, as certain answers will vary between different Macs and Tiger vs. Leopard, etc. (we'll assume you're running Leopard if you don't specify). And now, on to the questions!

Stu asks

I currently have a MBPro and I am thinking of spending some monies on a new iMac (mostly for videos etc.. but also because - well they're awesome. My question is about time machine. I have a WD external hard drive, would it be possible to link up the external drive to the iMac & then back up (wirelessly through the network) my MBP?

Yes, this is a supported feature of Time Machine. You just have to have Leopard running on both machines. On the iMac you need to share the external drive through AFP and then you should be able to select it in Time Machine on the MacBook Pro.

Michael asks

Here is a question for the next post. I am running OS 10.4.12 on a mac mini G4. I have an 80GB iPod Classic, that I sync my entire library to. It seems that every time I connect the iPod to my mac mini via usb, iTunes has to update anywhere from 50 to 80 music files. Why would it need to updated so many files each time if I am syncing my entire library?

Well there's really no way I can answer this question. Do you subscribe to podcasts, etc. However, I do have a suggestion. Create a Smart Playlist in iTunes that collects everything that's modified in the last day (or however long it generally is between syncs). That playlist should list what's being copied to the iPod during these updates and you should be able to figure out what's going on.

balloo4u asks

I have a G4 iBook running 10.5.2 I've begun using Mail.app for my e-mail. It doesn't seem seem to delete my expired .mac e-mail account. I've lloked for a file I cna chance the permissions on (as suggested int eh help file) but I'm coming up short. Any thoughts? [sic]

Frankly, I'm having a bit of a hard time understanding what's going on here. It seems like you're asking how to delete a .mac mail account from Mail.app. If that's right, all you have to do is go to the Preferences of Mail.app. In the Accounts tab just select the relevant account and hit the minus at the bottom of the Accounts list.

Otto asks

i have fast user switching set up. and i want to share the iphoto library across both users. so, it wouldnt matter which user imports the pictures.

We've covered this several times. The simple answer is to put the iPhoto library in a public folder that all user accounts can access, but this has some downsides (e.g. only the account that added a pic can modify it). The better solution is editing the Access Control Lists as described here and here. Both of the pages refer to Tiger, but at least one user at Mac OS X Hints suggests that it can be made to work on Leopard.

Anson asks

Is there any information as to how many cells are in a MacBook or MacBook Pro battery? I'm doing a comparison to a comparably equipped Dell to show my friend that they're not that expensive when compared to other current PC technology available, and Dell only mentions battery cell size instead of battery life.

Battery capacity is actually measured in amp-hours (or generally, for laptops milliamp-hours). If you go to the relevant tech specs you'll see that the MacBook battery has a rating of 55 watt-hours (watt-hours = amp-hours x voltage) while the 15" [MacBook Pro battery] is rated at 60 watt-hours (68 for the 17").

In the end, however, this kind of tech comparison is relatively meaningless because the different machines will put different loads on their respective batteries. What you really want to compare, in my view, is battery life. For that you should look for third-party benchmarking since you can't really trust any manufacturer's battery life estimates, including Apple's (though it's true that Apple is getting better).

Ben asks

I'm going to be buying a new Macbook soon, and I have a leopard Mac Mini running at home. I don't want to make the new macbook my default media computer - I have many many gigs of both video and music on a massive HD connected to the Mac Mini. I know that in my house I'll be able to use a shared library to access the music and play it from wherever I want, but that this doesn't work if I'm not on the LAN. I don't want to have all the music, but I'd like some part of it so that I can watch some movies and listen to my favorite songs. What I'd love to be able to do is sync music to that laptop in the same way that I sync certain playlists and movies to my iPhone. Is there any way to do this short of manually copying it over every time I add something new? Or is there any other way to solve my problem of what to do with that secondary computer in terms of media files?

This is an annoying problem that I think Apple should address directly in iTunes (especially considering the MacBook Air). However, I think I have a solution for you. There's a nifty syncing program called Martian Slingshot ($29.99) that has built-in iTunes integration. You run Martian Slingshot on both computers, the mini set as Publisher and the MacBook as Subscriber. Then you just choose which playlists on the mini you want synced to the MacBook. When you run Slingshot it will copy them over and sync them.

Brad asks

I have a Macbook (Model Identifier MacBook 3,1) - 2.2GHz Processor with 4GB of RAM. I am currently running Leopard which was the OS that can pre-installed when I bought the machine. Recently I have been having trouble getting my Macbook to go to sleep when idle despite having it set to sleep after 15 minutes of inactivity in the Energy Settings. The screen will turn off when idle but nothing else - also it doesn't seem to hibernate anymore when it is running out of battery. It sleeps (throbbing white light) when I close the lid or when I invoke Cmd+Option+Eject. I have read that some people have had similar problems when their logic board was on the outs. I don't think it is software related because it doesn't sleep even if left idle on the login screen. Any ideas on a possible solution or are you aware of any background software that may be preventing my Mac from going to sleep.

The main suggestion I always give to these sorts of problems is to reset the System Management Controller. There's an Apple Support Document (303319) that has all the details.

kalaj asks

Any one knows how to add multi subtitles for the iPhone video?

The iPhone does not natively support subtitles, so you'll have to merge the subtitles file into the video itself (i.e. you'll have to re-encode the video). We recently posted on an application called Submerge ($9) that does exactly this.

Paul asks

Regarding the Q/A on sharing the iTunes music with the Apple TV using a NAS with built in iTunes server... I have a new Apple TV and I have a D-Link DNS-323. So how do I get my Apple TV to see the iTunes server that is running on it? My Apple TV shows me an "password" that needs to be entered via iTunes for the Apple TV to talk to my iTunes, so how is this done on my NAS?

From what I can tell the Apple TV does not support streaming directly from an iTunes server on a NAS. It has to be routed through a Mac. In other words, it has to go something like NAS Router Mac (running iTunes) Apple TV. The only way to make the Apple TV see the NAS directly is to hack it with a plugin like ATVFiles, which is a non-trivial step and one that will likely void your warranty.

Josh asks

"what does the SDK release mean to me with a 1.1.2 jailbroken - unlocked iphone." I have lots of questions... Will I be able to use the apps created with SDK? Does this mean I have to update/jailbreak/unlock again? Are people still going to make apps for 1.1.1/2/3? I guess alot of other questions will have to wait until it is released, but for some reason i'm worried about this SDK release...

At this point you're going to have to have a firmware 2.0 iPhone to run software written with the SDK, which won't be released until June. The reason for this is that the code is signed by a digital certificate that is controlled by Apple. Developers with the SDK will only be able to run code on their own iPhones if they pay the $99 developer fee. They will not be able to distribute binaries. Now of course it's possible that the iPhone hacking community will be able to break this, but that's pure speculation at this point.