Starting with version 2.2.0, Flightmap automatically employs Windows file compression on itinerary files to minimize disc usage. For file compression, certain conditions have to be met:
- The storage volume must support file compression. Any volume formatted with NTFS will do, but FAT does not supported file compression—hence itineraries saved to your USB drive might not benefit from file compression.
Compression is disabled if there is a single
attachment in one of these formats:
Itinerary files with a lot of flights can be efficiently compressed using the LZW algorithm of Windows' NTFS file system—that's why Flightmap turns on the file compression for itineraries on NTFS volumes. Compression and decompression are very fast: the cost is some additonal CPU time required, but your computer actually has much less to read from your slow disc volume, so it's a very good deal. This holds true for SSDs.
When you attach certain media files to your flights, this deal gets off balance: JPEG pictures, videos and of course archive files are already compressed, so there is nothing to gain when using file compression on them. In addition, they also tend to be much larger than flight data, by a factor of 100 or even more. So if you have an itinerary with just a single JPEG picture, you don't gain any speed advantage by reading less from your disc, but you still have the cost of decompression for the whole (now even larger) file. That's the reason why Flightmap disables file compression if just a single one of these file formats is found among your attachments.
Compressed files are displayed in bright blue by the Windows Explorer.