In defense of the Windows x86-32 Port

[Andrew Dinn]

Hi Mark,

Please do note that the JEP is merely proposing to deprecate the Windows 
x86-32 port in JDK21. The implication of that is that removal will occur 
in a later release. So, the port will still be retained, and maintained, 
in the JDK17u and JDK21u long term support (LTS) releases i.e. x86-32 
will still be an option for deployment well beyond the arrival of JDK22.

regards,

Andrew Dinn
-----------
Red Hat Distinguished Engineer
Red Hat UK Ltd
Registered in England and Wales under Company Registration No. 03798903
Directors: Michael Cunningham, Michael ("Mike") O'Neill

On 26/02/2023 05:09, mark.yagnatinsky at barclays.com wrote:
> I saw this JEP draft today: https://openjdk.org/jeps/8303167 
> <https://openjdk.org/jeps/8303167>.  It suggests deprecating the 32-bit 
> Windows port of OpenJDK.
> 
> And even though it’s “just a draft” it does mention Java 21 (which is 
> pretty soon), so I thought I might as well put in my “two cents” now 
> instead of waiting to see whether or not this ends up going anywhere.
> 
> The draft is written as though the (primary?) purpose of the port is to 
> support running Java on 32-bit versions of Windows.
> 
> Those are indeed very rare, and getting even rarer.  But I appreciate 
> the 32-bit builds even though I haven’t run a 32-bit version of Windows 
> in ages.
> 
> Unlike MacOS, it is possible (and effortless) to run 32-bit executables 
> on 64-bit Windows.  There are at least 2 reasons to do so:
> 
> The obvious reason is that maybe someone has some native code they’re 
> calling via JNI, and they don’t have a 64-bit version handy.
> 
> The other reason is perhaps less obvious, and perhaps I’m the only 
> person in the world who considers this a “reason” at all, but it 
> motivated me to write this email so here it is:
> 
> The restriction to 32-bits is pretty effective as a poor man’s 
> substitute for a proper sandbox.
> 
> For example, the draft JEP talks about Project loom, a topic near and 
> dear to me.  When I first heard of Project loom, I wanted to run two 
> silly experiments.
> 
> The first experiment was to launch as many “platform” threads as I 
> could, and thus get a feel for how much they “cost”.  The second 
> experiment was to do the same for “virtual” threads.
> 
> I actually carried out the first experiment, on a 32-bit JVM.  I did not 
> dare to try the same experiment on a 64-bit JVM.
> 
> The reason is that I knew that with a 32-bit JVM, I would run out of 
> address space before anything bad happened.
> 
> But if I tried the same thing with a 64-bit JVM, then for all I know I 
> might bring my poor laptop to its knees and might even be forced to restart.
> 
> I’ve been eagerly awaiting Alexey Shipilev’s 32-bit port (is anyone else 
> besides him working on this?) ever since then so I could try the “loom” 
> part of the experiment.
> 
> I’ll be a bit disappointed if it never appears.
> 
> Anyway, that’s my two cents; thanks if you read this far.
> 
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