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#758: Empty Trash Through Terminal, Just a TRIM, iTunes and Sound Quality, iOS, Meet Flash


Happy Tuesday,

This week it’s Ben writing for Matt while he’s in California—a state fresh on my mind as I was there myself just 48 hours ago. Though I’m a Vermont-bred snow maniac, Nor’easters in March seriously cramp my style. One could say I picked the perfect week to travel as I just barely dodged the New England snow en route to the California sun. The big Apple news last week was of course the launch of iPad 2. Given the incredible success of its predecessor, I can’t say I was surprised to hear of lines wrapping around stores nationwide leading up to its launch. I missed a potential spot in line at the Beverly Hills Apple Store by sleeping in, so I decided to cut my losses. Instead of standing in line all day, I drove out to the desert to visit Joshua Tree.

All of the excitement surrounding iPad 2 was met with shock and sorrow as news broke of the devastating earthquake and accompanying tsunami hitting Miyagi Prefecture, Japan on Friday. As reports and terrifying video footage of the disaster spread, the hearts and thoughts of American citizens went out to Japan. In the days following the disaster, several organizations have started accepting donations to assist those affected. In a similar fashion to the company’s response to the 2010 Haiti earthquake, Apple has dedicated a portion of its iTunes Music Store to American Red Cross donations. If you’d like to help the earthquake and tsunami victims, please donate here.

Thanks for reading this issue of Tech Tails.


  Force Empty Trash Through Terminal  
  Delete, Trash

Last week I took a support call from a woman having trouble emptying the trash on her Mac. She kept getting an error message saying that the item could not be deleted. Often the cause of this is an application or process that is still running and using that file. Other times it is because of permission problems. In both cases, where restarting the machine doesn’t help, I’ve found that securely emptying the trash will solve it. In her case, it didn’t work.

The solution was found in Terminal, the Mac command line utility. For the majority of Mac users you’ll never use this app—it will sit in your Utilities folder gathering digital dust. In truth, this is a good thing, as reckless use of Terminal can lead to some pretty serious consequences for your operating system. Though if you have the basics down, you can do a fair amount with your machine by bypassing the graphic interface that we all know and love. To delete your trash through Terminal, enter or copy and paste the following command line exactly:

sudo rm -rf ~/.Trash/*

To delete another user’s trash (user_name is the user’s short name) enter or copy and paste:

sudo rm -rf /Users/user_name/.Trash/*

Once entered, you’ll be asked for your administrator password and your trash will empty. If you have a large amount of files in there, it may take a bit. This command only works for trash contained on the root drive; any external or secondary volume connected would have a different path. In that case, the command line would be:

sudo rm -rf /Volumes/DriveName/.Trash/*

These commands will work for OS 10.5 and 10.6; I’m unsure of whether or not they will work with anything older than 10.5. It’s also entirely possible that upon the release of Lion, this solution will no longer work. Apple has changed some of the commands used in Terminal between 10.5 and 10.6, and could continue to change commands as the OS evolves. I have found that periodically the Trash icon on your dock will still look like it’s full even though the formerly stuck files are gone. Just right click and empty trash, and it will now look empty. Use this information at your own risk!

  Just a TRIM  

Solid state drives (SSDs) are advertised as better than standard hard drives, and in most cases that’s true. There are no moving read/write heads or spinning platters, so there’s no time wasted while the drive rotates around to grab the next data fragment. Plus, the lack of moving parts means better battery life on portable systems. However, due to the way data is stored on a solid state drive, you will see a higher performance gain on reading data than writing it. Loading applications and documents will take almost no time at all compared to the same retrieval on a hard disk, but writing large amounts of data may not be that fast. The reason is because of the way a SSD stores data.

Picture a large storeroom with a row of shelves, and each shelf contains a row of egg cartons. Near the door of the storage room is a large whiteboard with a list of what is in each of the egg cartons. Any time someone needs to store some information, they write it on a slip of paper and put it into an empty spot in an egg carton, then go to the inventory list and mark down the location of that note. When someone needs to find a note, they consult the list so they know which egg carton to go to. If you no longer need a note, you go to the whiteboard and erase the reference to the note so others know that space can be reused. Seems like a decent system, right? Well, there’s one issue: No one ever goes into the shelves and does any housecleaning, so you have rows of egg cartons full of old notes that aren’t being used anymore.

When you delete a file, the directory portion of the file system (the whiteboard) is updated to show that the file is no longer needed so the space it takes up can be reused. However, the data is not actually removed from the hard disk (unless you specify a secure wipe, which is outside the scope of this article). For a standard hard drive, any existing (unused) data is overwritten by the new data in one pass, so to the user it’s transparent. Because of the way the memory cells work on a solid state drive, data cannot be overwritten; the storage cell must be emptied before something else can be put there.

Data on a solid state drive is stored in blocks, with each block containing multiple cells. Data can be written to each cell individually, but data has to be erased by the block. Remember those egg cartons? To save a note, you find an empty spot in an egg carton and drop the paper into it. To replace one of those pieces of paper, however, you have to remove every piece of paper from the egg carton, temporarily store them in another egg carton (known as a cache) dump all of the notes, then put only the notes that are still in use back into the original egg carton. Now there are empty spaces so you can save your new note, but two extra steps were needed just to store it. Since it all happens in a matter of microseconds, it doesn’t typically become a problem for small files, but when you start dealing with large files (such as editing movies) the slow-down in writes can become very noticeable.

This is where the TRIM feature comes in. TRIM, while capitalized, is not an acronym for anything; its purpose is to trim old data from the SSD. The operating system will watch for idle times (when no data is being written) and signal the drive to erase any storage locations that have been marked for deletion. Later, when data needs to be written to that space, there is no wait time since the space is already empty. The TRIMming happens in the background while you’re doing other things, so you aren’t even aware that it’s going on.

A lot of newer solid state drives either have TRIM support built in or the vendor has made a firmware update available to enable it. TRIM does not happen automatically, however; the drive needs to be told by the operating system when it’s safe to trim. Windows 7, Windows Server 2008, Linux 2.6, OpenSolaris, and FreeBSD already have TRIM support, but Mac OS X support was not scheduled to be included until version 10.7 “Lion” later this year. It was recently discovered that the newly released line of MacBook Pro “Thunderbolt” systems run an updated build of Snow Leopard that includes support for TRIM. As of the time this article is being written, the only drives supported are the ones Apple ships with the system, but that may change in the future as Apple evaluates other brands.

There are utilities available to do a manual TRIM on operating systems that do not have support built in; however, some of them could cause data loss if not used properly, so I will not mention them here. They fall under the category of “if you know how to use it, you’ll know where to look for it.”

  iTunes Music Store and Sound Quality  

According to the rumor mills, Apple is in discussions with some record labels to sell higher-quality versions of the music it sells in the iTunes store. The store’s offerings are currently “CD-quality,” which for more than twenty-five years has meant digital audio captured at 44.1 kHz sample rate and 16-bits available per sample. Apple is looking to up that to 24-bit audio and will, I assume, charge people to upgrade their libraries much as they did when they switched from 128kbps to the current 256kbps they offer. I’ve been looking around and all the usual comments are popping up about greed, sound quality, the death of audio quality and quality music, the relevance of any of this with a public that almost solely uses crappy equipment to listen to music, and so on.

One thing pretty much everyone agrees with: Apple’s change from 128kbps DRM-encoded music to the current 256kbps non-DRM format was significant. Pretty much anyone can hear the difference on pretty much any equipment. In fact, some studies show that more people could tell the difference when the tests were done using low-quality playback devices such as earbuds and small speakers than with high-end gear. This certainly raises an interesting point for those who ask if audio quality matters when people are listening to earbuds and those on the other side who wonder why you would spend a lot of money on a good stereo. The conclusions are obvious: good-quality audio and good equipment make for better sound.

So what about the switch from 16-bit to 24-bit? My take is exactly that: so what, at least mostly. For the vast majority of recorded music, 24-bits is a non-issue, for one. Anything recorded using less than 24-bit technology will see no gains at all. The source material is fixed and cannot be improved upon. This basically means that for everything recorded before about 1997 (release of ProTools 24-bit) and even for most mainstream releases recorded after that until very recently, there will be no inherent benefit going to 24-bit.

Now, some material will certainly be remixed and remastered and sound better, but even in those cases the majority of improvements, if there are any, will be from artistic choices and not from increased audio quality. So don’t rush out and download the whole Rolling Stones library again just because it’s 24-bit. When they recorded Sticky Fingers, for instance, the state of the art allowed for about 75db dynamic range in the studio and around 60db on a mastered LP. That doesn’t even push 16-bit technology to its limit, and that was the maximum, in practice.

Most recordings use much less dynamic range than the maximum available. And that’s something to realize: it’s only in extremely dynamic material recorded natively in 24-bit that the 24-bit material will be perceived as superior to the listener. A Ferrari and a Jetta both get you home at the same time if you drive 55 mph. And then of course come all of the usual arguments about earbuds and small speakers, and that while 256kbps sounds pretty good with 16-bit, it will likely have a bigger effect on 24-bit recordings, and so on. If Apple really wants to improve things, they should start offering everything in uncompressed 16/44.1. That would certainly be a real step forward.

  iOS, Meet Flash  

Tired of seeing the lego-like block symbol when you try to browse your favorite Flash-based website on your iOS device? Wallaby, a program produced by Adobe (the creators of Flash itself), may change all that.

Wallaby is an experimental program that turns Flash-based content into HTML5, basically making the content viewable on your iPhone, iPad, and iPod touch. Currently, the quality and performance of Wallaby is questionable at best, but once all the kinks are worked out, this tool may make your devices much more versatile on the Web.

Flash is currently a proprietary closed solution for displaying some types of Web content. Most content in Flash is in the form of Web video. YouTube, Vimeo, and most other video websites—as well as some Facebook games, some splash pages for websites, and a whole lot of games—use Flash extensively..

The reason you don’t see many issues on your iOS device on websites is because Web developers have actually made non-Flash-based versions of their websites. These versions may or may not look the same, but they have the goal of making their content viewable on lucrative mobile browsers.

Web developers pour tons of time and money into making Flash-based websites that look great on Web browsers with Flash installed. After all this time they spend on the Flash version, they then pour tons of time and money into a non-Flash-based version to satisfy people who either don’t want to or don’t have the capability to run Flash.

Wallaby has the capability to streamline a lot of the process needed to convert a website to a version compatible with browsers that either don’t have Flash installed or don’t support Flash. For this reason, Wallaby is awesome for those of us who frequent Flash sites but can’t use them on our spiffy new iPads.

Just to note – Wallaby is not yet out of development; it is still considered experimental and may never see the light of day as a real tool, so take all of this with a grain of salt and hope for the best!

  TT SPECIALS | 3/15/11 - 3/22/11  
   iPod touch 32GB (4G), AppleCare Plan + Free MiLi Blue/White AC Adapter!
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   $20 price drop! Verso Leather Case for iPad (red)
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   Save $20! Twelve South Magic Wand, Magic Trackpad, + Apple Wireless Keyboard (No Box)