Use the Scratch Folder for Performance

 
     Attention heavy disk IO users! Think your IDD G5 should be faster when rendering/editing/compiling? Read on..

     Many applications that use large files, or access data in frames, or play back dynamically editable content require disk input/output (IO) while you work in the application. Why? Simply because the data that the application is manipulating is far too large to be held in the G5's memory. Every application can be looked at simply as instructions to modify data, and the more data there is to be modified, the longer your computer will take to perform the instructions in the application. Most apps modify only small amounts of data -- such as an email program when you are creating a new email message. For performance sake, an application will move the data that needs to be changed into the computer's memory, or RAM where changes can be made very quickly. However, if the data that is being manipulated is large, or the application is designed to manipulate large chunks of data, this data is read into memory from disk, modified, then moved back to disk in chunks. Apps that work this way include Final Cut Pro, After Effects, Photoshop, Illustrator, etc. Apps that work with pictures, video, and audio very typically work not only with memory but also with your disk using the file created by the app, or a file known as a scratch file.

     Now, as you may or may not know, your home folder (the folders mounted on the G5 when you login where you save all your files) are not on the machine you are working on. They exist on a server across Quinnipiac's network. Because of this, programs that are working with files in your home folder and require disk IO must wait for the data to move from the server, across the network, and up into the G5's memory. This can be slow (or 'expensive' in IT talk) for applications, and you witness the expensive transaction by poor performance in the application. Video may be choppy. Audio may slice. You may have to wait for some time when applying mathematical transforms on entire chunks of data, like applying a filters or effects to an image.

     The solution? Work with your data on the local harddrive, and when you're done, move it back to the server (your home folder). I have set up a folder on 'Macintosh HD' called 'Scratch Folder' where you can save working files that require high IO. The G5's disks are SATA disks, and IO to the local disk is immensely faster than IO to a disk across the network. Just remember to move your files back to your home folders when done, and empty the scratch folder to avoid using up all the free space on the local disk.

     Many applications (Adobe, Alias, Macromedia) have settings within each application to set the 'scratch disk', or a place the app can use to hold temporary data while you work. I think you will find that changing the scratch disk setting to 'Macintosh HD/Scratch Folder' will greatly improve the performance of these applications.

~B