Sharing Calibre library on a removable drive

[juliebarkley]

Based on what I have read in the forums here, I think that it is possible to share a Calibre library which is on a removable hard drive (ie. disconnect it to use with each computer separately). However, the two computers I am interested in using it on have different versions of Calibre installed as one is much older than the other. If I edit the library in the newer version (eg. change metadata or delete items), will it cause problems when using it on the older version? Or vice versa? The library was originally created using the older version of Calibre, if that makes a difference.

[theducks]

How old? XP right?

The DB structure has been stable for quite a while, so that should not be an issue.
Obviously, more modern features and plugins will NOT be available

[BetterRed]

@juliebarkley - there is no one word answer.

Firstly it depends on which old version of calibre, the calibre database schema (detailed design specification) hasn't changed for a very long time, I'm not sure when that was, or which version. Perhaps you can tell us which 'old' calibre version and which version of Windows.

If your old version is installed on Windows XP then calibre should be at version 1.48 (if not why not ?). The database schema hasn't changed since 1.48 was released, so in that scenario you should be OK.

If your old version is installed on Windows Vista or later then why not make its calibre installation current? Allegedly there are some low end CPU's that can run Vista, but they don't have the wherewithal ('advanced' floating point instructions) to run calibre - but they're rarely seen in consumer products.

There is at least one user written plugin that modifies the database schema - Multi-column Search (MCS). I'm uncertain if older versions of calibre can cope with those changes. In the MCS case the plugin cannot be installed on older versions.

If you don't have a robust library backup/restore process in place already, I suggest you address that issue first. Once you have that in place then you can go ahead and 'see what happens'. If something goes horribly wrong you can restore the most recent backup.

BR

[juliebarkley]

Not XP, actually Snow Leopard (10.6.8) on a 2006 Mac Mini . However, Calibre is version 1.48.0. The newer computer is running Yosemite and doesn't have Calibre installed yet, but it will be the most recent version.

So it sounds like it will probably be okay? I do have a backup of it if worst comes to worst, but it's a pretty big library and it would be a pain to have to restore it.

[theducks]

Backing up is doubly important with External drives.
They tend to get knocked around and don't bounce well

I do recommend something faster than a SD/Pen drive for larger libraries

[mbovenka]

Originally Posted by theducks

Backing up is doubly important with External drives.
They tend to get knocked around and don't bounce well

I do recommend something faster than a SD/Pen drive for larger libraries

+1 about the external drive . But the speed of your drive isn't all *that* important when running Calibre, except for startup time. Calibre loads the metadata.db into a memory structure at startup and uses that afterwards. And USB3 sticks are pretty nippy anyway. USB2 is another matter...