On Wed, 2009-10-14 at 11:46 +0100, Emmanuele Bassi wrote: > everyone asking for a plain text format (or even an XML format) for > *storage* should be forced to get only that on their machines, but > should also be barred from complaining why their boot process takes a > minute instead of 10 seconds. and no: having plain text storage and > adding a binary cache is not a solution. > > ciao, > Emmanuele. There are key differences: - FS are usually implemented very carefully. They tend to be part of kernel. On the other hand desktop applications are designed much more 'speedy'. Sometimes application hangs (much more frequent then kernel locks IMHO), sometimes it crashes. - FS have much better support of tools which recover the data. Well - you cannot edit by XML editor but both FAT and EXT2/3/4 have numerous tools that recovers data - even less popular systems like reiserfs have them. I haven't seen them for many application binary format. - The more common code the more profitable optimalization is. If the format is read once at startup it makes much more sense to have it more readable then fast. On the other hand if it is used constantly... - Hardware limitations - on paged systems with big costs of switching etc. it makes sense to have data padded. It simply makes sense to be able to read in 512 kB - 4096 kB blocks. Unpadded format would be much more costly (it would required to look for end of metadata and possibly copy from one place in memory to another). However one page is load looking through it is cheap as it is already in random access memory. Since even cache operates on virtual memory as long as block is continuous it makes practically no difference in speed. - FS are rarely compressed. Text-based formats are much compressable and backup of them would take much less space. Regards
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