Re: Resurrect discussion: Mixing 32 and 64 bit distro

[Corinna Vinschen <corinna-cygwin at cygwin dot com>]

On Feb 12 08:58, Ryan Johnson wrote:
> On 12/02/2013 8:40 AM, Corinna Vinschen wrote:
> >Hi guys,
> >
> >
> >I slept a bit bad tonight.
> >[...]
> >So, I'm inclined to resurrect this discussion.  I'd like to hear your
> >point of view and why you're rating one over the other (separate
> >distro vs. mixed distro).  Personally I'm really not sure what is
> >more important, a full distro right from the start, or a clean
> >separation.
> Two thoughts:
> 
> 1. How is this significantly different for the end user than the 1.5
> -> 1.7 migration was? That essentially required a full upgrade as
> well, with no inter-op allowed, and side-by-side installs common for
> a while. I don't know how much pain it was for the package
> maintainers to get their stuff working under 1.7 -- presumably at
> least a couple ran into issues.

The 1.5->1.7 transition did not invalidate the existing POSIX-only
binaries.  They still work today.  A few executables in our distro
have been built pre-1.7...

> I'd suggest that a few brave maintainers try creating 64-bit
> packages (mintty already seems to work), and if it goes relatively
> smoothly we forget mixing; folks whose favorite package is missing
> at first can just keep using 32-bit 1.7 until the early adopters
> have broken a path for them.
> 
> BTW, would it make any sense to talk about having 32-bit binaries
> made for 64-bit cygwin, compiling them specially for inter-op with a
> 64-bit cygwin1.dll? Kind of how most 64-bit linux default to 32-bit
> binaries on a 64-bit kernel? There are fairly good reasons for small
> binaries operating on small datasets to stay 32-bit,

I don't understand this point.  A 64 bit binary usually doesn't take
much more space than a 32 bit binary, given that most data access,
jmps and calls are using 32 bit PC-relative instructions on 64 bit.
Also, int's are still 4 byte, so there's not a lot to do to keep
the data set about the same size as on a 32 bit target.

I also don't see how Linux 64 bit distros default to 32 bit binaries.
Of the 3067 binaries in my /usr/bin dir on x86_64 Fedora, only 3(!)
are 32 it binaries, and those have 64 bit counterparts.


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat