The CissyPod has a 30 GB disk space, but without resorting to some more esoteric third-party tools we will probably be limited to just 5 GB, because of the wasteful way iTunes manages disk space.

Filesystem                Size   Used  Avail Capacity  Mounted on
/dev/disk0s3               37G    34G   2.8G    92%    /

The iPod, iTunes and iPhoto are really easy to use, but you pay for that convenience with gigabytes of disk space.

All synchronisation with the iPod is done through iTunes, even when movies or pictures are concerned. Synchronisation is one-way. iTunes can only copy files onto the iPod, but not download files from the iPod back to the computer. I assume that this is a concession to the music industry. Automatic synchronisation will add and delete files on the iPod to create an exact replica of your iTunes library. As a result you have to have a copy of every song or video on the computer hard disk as well. This stops being convenient when the storage capacity of the iPod is big enough that you cannot afford to just reserve that much space on your computer.

One measure would be to turn off automatic synchronisation and manage files manually. That eliminates a good deal of convenience, but we may be forced to do just that. But even with manual synchronisation, you cannot copy media files directly onto the iPod. Everything has to go through iTunes first, which leads to extra steps and often redundant copies of the same file. So when copying a CD, you cannot put it directly to the iPod, it has to take up disk space first that you need to clean up later. A CD in MP3 format is not all that huge, but it gets worse with DVDs. iTunes cannot import DVDs directly (this is apparently illegal nowadays), so that you have to use some other software to read the DVD and convert it into a file that the iPod can play. That file first goes to your hard disk, then needs to be imported into iTunes, making another copy of the same file (a file that takes up several hundred MB), and can then finally be uploaded to the iPod.

iTunes can also put your photos on the iPod. In order to save space on the iPod, and probably because it cannot handle files above a certain resolution, the pictures are first reduced in size. For some reason copies of these thumbnails are also cached on the computer. You can delete the cache, but it will be recreated. In our case, that cache is actually bigger than the library it represents. Another 2 GB to write off.

1.8G    iPhoto Library//iPod Photo Cache
3.3G    iPhoto Library/

Time to look at third-party tools or my external Firewire disk.