The biggest "change" that occurs in going from 8bit to 16 bit to 32 bit etc is the size of the numbers the programming languages can use without "fudging".

These mathematical issues go well beyond my level of mathematical competence. But basically computers in their binary state use the bitness to the power of 2 to determine the size of integer numbers. For example a 32 bit operating system can only address 4Gb of memory. (32 raised to the power of 2). Similarly hard disks are limited to the same number of "addresses" to store information. So going to a 64bit machine results in much larger numbers. So a 64bit device is theoretically limited to 16 Exabytes of memory for example. I somewhat silly amount of memory we might think. But I remember a time when DOS ran is the base 640k and setting a system to use "Hi" memory was almost a black art. It was considered adequate at the time when hard disks topped out a 10mb and digital video was a multi million dollar investment.

Thunderbird has suck with a 32bit executable for windows, and it has caused a few issues when folders exceed 4Gb in size for example. We will move to a 64bit version and there is a non release version around now that folks are testing. There are already 64 bit OSX (there is only 64 bit OSX) and the same for Linux.

The future is not clear. It could be that bitness becomes superseded by some completely new thing like quantum computing. All we can do is hang on for the ride and hope for the best.

Ah, of course. I was thinking RAM/processing speed for an email app, and not folder size. IBM learned too slowly that cheaping out on the 8088 vs 8086 created the need for "fudging" to address RAM (but then, they learned too slowly on the entire PC concept.) Thanks for the quick and clear answer - and your last paragraph. That's what makes all of this so much fun! (BTW, Thunderbird continues to be awesome!)

Matt said

Thunderbird has suck with a 32bit executable for windows, and it has caused a few issues when folders exceed 4Gb in size for example. We will move to a 64bit version and there is a non release version around now that folks are testing. There are already 64 bit OSX (there is only 64 bit OSX) and the same for Linux.

Any idea when a 64bit Windows version might be released for us to use?

Thanks

There is a 64 bit build, See http://ftp.mozilla.org/pub/thunderbird/releases/60.7.1/win64/

Due to changes in the build infrastructure, the daily developer build is now in the release FTP store for each release, but as a proper release it still has not made it. I feel it will probably still be a couple of releases and given they are almost annual, it will be a while. This is simpy because there are more pressing things the developers need to fix than the few bugs unique to 64bit that are still around. There was discussion around the V68 release which is only a few months away, but I never saw anything actually resolved so it will most likely be at least a year.

The developers are hard at it "migrating" Thunderbird's core to rely less on Firefox which is going in a different direction. Modernizing it into the bargain. Lots of it is around 20 years old. At least Mozilla have done the heavy lifting on moving a lot of it to 64bit. a lot of the mail parts have not received the attention they needed in recent years.

The steering council is moving at higher levels to move development increasingly off Mozilla infrastructure. Things like the new Thunderbird.net web domain and having an add-on environment separate from that used by Firefox. It is a big migration that is costing a fortune really. But when it is done Thunderbird will be able to grow having removed a lot of the old technical debt that has been holding it back.

Matt,

Thanks for your detailed explanation on the status of the 64bit builds.

This 64 bit build you posted above. Is it essentially the same as the released 32bit version in terms of stability and compatibility with plugins, or is it still not really ready for prime time?

It is close and there are lot of purists that search until they find a 64bit version for their 64bit operating system, but the reality is there should not be any appreciable difference, and there ARE 64bit only bugs. Is it ready for prime time? That is difficult to say. The release drivers obviously do not think so, or they would be offering it. So to err on the side of caution, despite using it myself, I would have to say no.

I have been looking for a 64bit mail reader and thought I found one with a fork of Thunderbird, but it was discontinued.

So from I can gather that although this version may have the added benefit of being 64 bit and what comes with that, there are still enough issues with it to make it not worthwhile yet?

Because when it comes down to it, I still need it to reliably work to read my mail.

Thanks