<oembed><type>rich</type><version>1.0</version><author_name>npub1f2nvlx49er5c7sqa43src6ssyp6snd4qwvtkwm5avc2l84cs84esecrwet</author_name><author_url>https://nostr.ae/npub1f2nvlx49er5c7sqa43src6ssyp6snd4qwvtkwm5avc2l84cs84esecrwet</author_url><provider_name>njump</provider_name><provider_url>https://nostr.ae</provider_url><html>📅 Original date posted:2015-12-09&#xA;📝 Original message:On Wed, Dec 9, 2015 at 6:59 AM, Mark Friedenbach &lt;mark at friedenbach.org&gt; wrote:&#xA;&gt; Greg, if you have actual data showing that putting the commitment in the&#xA;&gt; last transaction would be disruptive, and how disruptive, that would be&#xA;&gt; appreciated. Of the mining hardware I have looked at, none of it cared at&#xA;&gt; all what transactions other than the coinbase are. You need to provide a&#xA;&gt; path to the coinbase for extranonce rolling, but the witness commitment&#xA;&gt; wouldn&#39;t need to be updated.&#xA;&gt;&#xA;&gt; I&#39;m sorry but it&#39;s not clear how this would be an incompatible upgrade,&#xA;&gt; disruptive to anything other than the transaction selection code. Maybe I&#39;m&#xA;&gt; missing something? I&#39;m not familiar with all the hardware or pooling setups&#xA;&gt; out there.&#xA;&#xA;I didn&#39;t comment on the transaction output. I have commented on&#xA;coinbase outputs and on a hard-fork.&#xA;&#xA;Using an output in the last transaction would break the assumption&#xA;that you can truncate a block and still have a valid block. This is&#xA;used by some mining setups currently, because GBT does not generate&#xA;the coinbase transaction and so cannot know its size; and you may have&#xA;to drop the last transaction(s) to make room for it.&#xA;&#xA;That a block can be truncated and still result in a valid block also&#xA;seems like a useful property to me.&#xA;&#xA;If the input for that transaction is supposed to be generated from a&#xA;coinbase output some blocks earlier, then this may again run into&#xA;hardware output constraints in coinbase transactions. (But it may be&#xA;better since it wouldn&#39;t matter which output created it.). This could&#xA;likely be escaped by creating a zero value output only once and just&#xA;rolling it forward.</html></oembed>