Device drivers are critical of many reasons. They sit between the operating system and an internal or external device. They have to operate inside the operating system itself, unlike applications. If the driver is flaky, the whole system will crash, unlike application crashes.

This is the reason why I think when shopping for external gear such as external audio devices, the quality and support of the device driver is as important as the quality of the DAC (digital to analog conversion), or the ADC (analog to digital conversion) circuits.

One way to check this out is to do a web search and find out if a certain vendor and product is mentioned a lot, either positively, or negatively. Another thing is to stress-test the device connection. One way is to put the laptop or computer to sleep mode, and restart it, and see if the device is still talking to the computer. If this is a problem, you need to constantly restart the laptop for live performances — actually if possible this is good to do, anyway, so that any issues with broken device drivers might not happen during the show.

I’ve written six entries about computers and audio now, so I will switch to write a set about mastering.

You could read more about the actual specifications of Firewire and USB at Wikipedia.

Anyway, with the advent of the new USB 2.0 spec, both protocols have about the same speed, if we exclude Firewire 800. USB 1.0 is mostly used for keyboard and similar devices that don’t need fast connections.

For me, the biggest selling factor for Firewire is the star-based protocol, versus the client-server protocol for USB. This means that you could hook together multiple Firewire devices. With USB, you need to have hubs between in order to have multiple connections working.

The other thing good to remember is that in both cases the protocols provide charging via cable — you just need six-pin Firewire connectors (some PCs only have four-pin connectors). However, the amount of power trickled via the ports could drain the battery fast, or even worse, cause problems with external firewire devices due to sudden blackouts of power.

So, if you use Ableton Live or something similar with external Firewire or USB 2.0 audio boxes, always provide external power to avoid problems during live shows. You could also get hubs that provide external power, but it’s just best to plug the external devices with their own power supply.

The application preferences are stored in the MacOSX home directory, or ~/Library/Preferences. Why is this good to know? Well, there are some few cases where an application suddenly won’t start, or if it starts, it has weird values that causes problems. One way, if possible the last one, is to remove the preferences and start fresh.

The preference file should have an indication of the actual application name. You could also double-click on the preference file, and the so called plist editor will open up with information about the preferences. Anyone who knows could even change the values via the plist, but it’s usually good to make a backup of the preference file so you could restore things back in case the application stops working.

The plugin components, AUs, are placed in either /Library/Audio/Plug-Ins/Components or ~/Library/Audio/Plug-Ins/Components. The ~, or tilde, stands for the home directory.

The reason there are two possible locations is that the /Library level is global for all users, while the ~/Library is local for the currently running user. In most cases it’s best to install the plugins globally. Hence most installers will place the AU plugins into the ~/Library location. It’s good to know this location in case you have to install the plugin by hand, or remove it of some reason. It’s also good to maybe do backups of this directory from time to time, even if I personally have backups of all the install program for specific plugins, as the plugins might install patches, documentation and other data files.

Logic will actually run a program called AUVal to validate any AU plugins installed, it will make sure that the plugin could properly run, as a lot of supposedly DAW related problems could be a result from a badly working plugin. AUval is a command line tool, so if you are interested, you could also run this by hand. Ableton Live is not running AUVal.

As for where the patches are possibly installed, this is not a standard. Usually you could find them installed in the /Library/Application Support/, somewhere inside there, or then use Spotlight with a known patch name to find where they were located. Fortunately, most plugins save the patch directory as a preference, so next time you open up patch files, you could quickly find the rest. I’ve even seen some installers placing documentation inside the ~/Documents folder, not in the /Documentation folder which I would think is the most obvious place for system-wide documentation. Or, Ableton Live has its PDF documentation file inside the main directory that you download when installing Live.

Today with MacOSX (and Windows) you could have multiple applications running multiple processes on the system. If the processes are not active, they are in sleep mode. This means they will not take any CPU resources, and any memory they are using is purged out via virtual memory if they are in the background.

The problem, however, is if the processes are trying to do something. Examples of this is any kind of network activity, such as polling a web address. With JavaScript today, there’s more and more web pages that constantly check for updated data. Same with email services, they could go out and look for new mails, for example from mail services that are slow to respond.

So if possible, if you worry about not having enough CPU cycles for audio work, just quit any applications that might run and cause unnecessary CPU load: Safari, Mail.app and so on.

Some think that Spotlight is stealing cycles when it does an index. The biggest hit is really if there’s a brand new installation, or a big set of new files that Spotlight needs to index or re-index, otherwise Spotlight is not taking that much concerning CPU traffic, so there’s no need to turn it off (there’s a secret way of doing it, but I will not mention it).

Another thing worth disabling, especially with Ableton Live in live situations, is WiFi. Otherwise the WiFi service is constantly checking for networks that could arrive and disappear, sometimes quite frequently in case the network signal is weak.

If you have removed unnecessary files (check /Library/Caches/ on the Mac that sometimes could have a lot of old cached content), and you still don’t have enough space, there’s maybe applications that have installed lots of content into the hard disk. As an example, Apple Loops are placed into /Library/Audio/Apple Loops/. Another place good to check out is /Library/Application Support/.

Now, unfortunately various applications assume that they could find content in the pre-defined places, so you can’t just move it to another disk. What you could do is either to make an Alias (Make Alias in the Finder File menu, or Command-L) or if that does not help, make a symbolic link via the command line tool. The alias should be made on a folder on the other disk, and then renamed so it’s the same as the original folder on the system disk is named. This is where it’s good to first rename the original folder, copy over everything to a new location, make an alias, and then drag the alias back to the original position and give it the same name as the original file. If all that works, then remove the original folder.

Now, it all depends if the application could resolve aliases. There are some programs that due to bad programming or otherwise can’t resolve aliases. In this case you need to make a symbolic link in the command line tool (The command line is in the /Applications/Utilities folder).

As before, copy over the contents to the new location, rename the original file, then in the command line type in something like:

$ ln -s /Volumes/OtherDisk/Folder '/Library/Application Support/OriginalFolderName'

You have to use the ‘ ‘ notation if the folder has a space in the name. The -s option tells that this is a symbolic link so it works across multiple volumes (disks). The /Volumes directory has all the mounted hard disks, where the disk name is the same as you see in the Finder.

A couple of notes, first practice before you do a critical operation, and always have a backup in place in case something bad happened.

To get more blog postings happening, I will start with small mini-five series postings. Seems I’m most productive when I have to deliver material. This first series is about computer systems and performance concerning audio productions. I will use the MacOSX system as the basis, as I work with it every day, even developing applications for it, but many of these topics cover the Windows system, as well.

First about the system disk and available disk space. The main operating system is using the hard disk to page out and in pieces of memory, this is called virtual memory paging. When you start an application, a lot of memory objects are created, and they all can’t fit into memory. So what the system does it to look when one of those memory blocks was accessed, if it was long time ago it is moved over to the hard disk. When this memory object is suddenly needed, it’s loaded back in.

Now, this means that there’s a lot of disk activity happening. If there’s more real memory, there’s less need to page out the memory pages (as they are called), or paged back in. So if you add more RAM, then things are faster.

Secondly, if the main disk is very full, it will take longer and longer to find disk sectors that could fit various pages. So the second rule is to never let the system hard disk get too full. My own rule is never to let it have less than 10Gb free space.

You could use Omnidisksweeper and similar tools to find what files and folders on the system disk use most disk space, and either delete them or move them to another hard disk. More in the next installment about this one.