Add thanks to gabriel & william; fix links

_site/essays/2018-01-01-home-backups.html

@@ -41,9 +41,9 @@ <h3 id="why-not-an-off-the-shelf-nas">Why not an off-the-shelf NAS?</h3>
 <p>In the past, I tried one (it was a Buffalo model). I wasn’t impressed by the software (which was hard to upgrade, install other stuff on it, maintain, etc), the power consumption (this was several years ago, but <em>idle</em> the two-drive system used over 30watts, which is the same power that my similarly aged quad core workstation uses when idle!). Also, a critical element of this system for me is that there is an off-site component, so getting that software on it is extremely important, and I’d rather have a well-supported linux computer to deal with rather than something esoteric. Obviously this depends in the particular NAS you get, but the system below is perfect <em>for me</em>. In particular, setting up and experimenting with the below was much cheaper than dropping hundreds more dollars on a new NAS that may not have worked any better than the old one, and once I had it working, there was certainly no point in going back!</p>
 <h3 id="hardware">Hardware</h3>
 <ul>
-<li><p>$70 - <a href="http://amzn.to/2zggJoh">Raspberry Pi 3</a> (That’s an affiliate link. Here’s <a href="https://www.amazon.com/CanaKit-Raspberry-Complete-Starter-Kit/dp/B0778CZ97B/">one that isn’t</a>). This consumes very little power (a little over 1W without the disks, probably around 10W with them spinning, more like 3W when they are idling), takes up very little space, but seems plenty fast enough to act as a file server. That price includes a case, heat-sink, SD card, power adaptor, etc. If you had any of these things, you can probably get a cheaper kit (the single board itself is around $35). Note that you <em>really</em> want a heat-sink on the processor. I ran without it for a while (forgot to install it) and it would overheat and hard lock. It’s a tradeoff that they put a much faster processor in these than in prior generations – I think it’s worth it (it’s an amazingly capably computer for the size/price).</p></li>
-<li><p>$75 - Three <a href="http://amzn.to/2BluHHj">external USB SATA hard drive enclosures</a>. You might be able to find these cheaper – the ones I got were metal, which seemed good in terms of heat dissipation, and have been running for a little over a year straight without a problem (note: this is actually one more than I’m using at any given time, to make it easier to rotate in new drives; BTRFS, which I’m using, allows you to just physically remove a drive and add a new one, but the preferred method is to have both attached, and issue a <code>replace</code> command. I’m not sure how much this matters, but for $25, I went with the extra enclosure).</p></li>
-<li><p>$170 - Two <a href="http://amzn.to/2C1lc3E">2TB WD Red SATA drives</a>. These are actually recent upgrades – the server was been running on older 1TB Green drives (four and five years old respectively), but one of them started reporting failures (I would speculate the older of the two, but I didn’t check) so I replaced both. The cheaper blue drives probably would have been fine (the Greens that the Blues have replaced certainly have lasted well enough, running nearly 24/7 for years), but the “intended to run 24/7” Red ones were only $20 more each so I thought I might as well spring for them.</p></li>
+<li><p>$70 - Raspberry Pi 3. This consumes very little power (a little over 1W without the disks, probably around 10W with them spinning, more like 3W when they are idling), takes up very little space, but seems plenty fast enough to act as a file server. That price includes a case, heat-sink, SD card, power adaptor, etc. If you had any of these things, you can probably get a cheaper kit (the single board itself is around $35). Note that you <em>really</em> want a heat-sink on the processor. I ran without it for a while (forgot to install it) and it would overheat and hard lock. It’s a tradeoff that they put a much faster processor in these than in prior generations – I think it’s worth it (it’s an amazingly capably computer for the size/price).</p></li>
+<li><p>$75 - Three external USB SATA hard drive enclosures. You might be able to find these cheaper – the ones I got were metal, which seemed good in terms of heat dissipation, and have been running for a little over a year straight without a problem (note: this is actually one more than I’m using at any given time, to make it easier to rotate in new drives; BTRFS, which I’m using, allows you to just physically remove a drive and add a new one, but the preferred method is to have both attached, and issue a <code>replace</code> command. I’m not sure how much this matters, but for $25, I went with the extra enclosure).</p></li>
+<li><p>$170 - Two 2TB WD Red SATA drives. These are actually recent upgrades – the server was been running on older 1TB Green drives (four and five years old respectively), but one of them started reporting failures (I would speculate the older of the two, but I didn’t check) so I replaced both. The cheaper blue drives probably would have been fine (the Greens that the Blues have replaced certainly have lasted well enough, running nearly 24/7 for years), but the “intended to run 24/7” Red ones were only $20 more each so I thought I might as well spring for them.</p></li>
 </ul>
 <h3 id="cloud">Cloud</h3>
 <ul>

_site/essays/2018-01-16-how-to-prove-a-compiler-correct.html

@@ -175,6 +175,8 @@ <h2 id="proving-things">Proving things</h2>
 <blockquote>
 <p>As stated at the top of the post, all the code in this post is available at <a href="https://github.com/dbp/howtoproveacompiler" class="uri">https://github.com/dbp/howtoproveacompiler</a>. If you are looking for more, check out <a href="https://xavierleroy.org/courses/Eugene-2012/">Xavier Leroy’s Oregon Programming Languages Summer School Lectures</a> (videos are <a href="https://www.cs.uoregon.edu/research/summerschool/summer12/curriculum.html">here</a>, scroll down to find them).</p>
 </blockquote>
+<p><br /></p>
+<p>Thanks to current and former <a href="http://prl.ccs.neu.edu">PRL</a> members, in particular <a href="http://gallium.inria.fr/~scherer/">Gabriel Scherer</a> and <a href="https://williamjbowman.com/">William Bowman</a>, for providing useful feedback on drafts of this post.</p>
 <p><br /><br /></p>
 <h2 id="addendum-termination">Addendum: termination</h2>
 <p>This example was so tiny we haven’t run into something that <em>will</em> be really common: imagine instead of the compile function shown above:</p>

_site/rss.xml

@@ -162,6 +162,8 @@ Qed.</code></pre>
 <blockquote>
 <p>As stated at the top of the post, all the code in this post is available at <a href="https://github.com/dbp/howtoproveacompiler" class="uri">https://github.com/dbp/howtoproveacompiler</a>. If you are looking for more, check out <a href="https://xavierleroy.org/courses/Eugene-2012/">Xavier Leroy’s Oregon Programming Languages Summer School Lectures</a> (videos are <a href="https://www.cs.uoregon.edu/research/summerschool/summer12/curriculum.html">here</a>, scroll down to find them).</p>
 </blockquote>
+<p><br/></p>
+<p>Thanks to current and former <a href="http://prl.ccs.neu.edu">PRL</a> members, in particular <a href="http://gallium.inria.fr/~scherer/">Gabriel Scherer</a> and <a href="https://williamjbowman.com/">William Bowman</a>, for providing useful feedback on drafts of this post.</p>
 <p><br/><br/></p>
 <h2 id="addendum-termination">Addendum: termination</h2>
 <p>This example was so tiny we haven’t run into something that <em>will</em> be really common: imagine instead of the compile function shown above:</p>
@@ -245,9 +247,9 @@ compile&#39; (<span class="dt">Times</span> a1 a2) <span class="fu">=</span> com
 <p>In the past, I tried one (it was a Buffalo model). I wasn’t impressed by the software (which was hard to upgrade, install other stuff on it, maintain, etc), the power consumption (this was several years ago, but <em>idle</em> the two-drive system used over 30watts, which is the same power that my similarly aged quad core workstation uses when idle!). Also, a critical element of this system for me is that there is an off-site component, so getting that software on it is extremely important, and I’d rather have a well-supported linux computer to deal with rather than something esoteric. Obviously this depends in the particular NAS you get, but the system below is perfect <em>for me</em>. In particular, setting up and experimenting with the below was much cheaper than dropping hundreds more dollars on a new NAS that may not have worked any better than the old one, and once I had it working, there was certainly no point in going back!</p>
 <h3 id="hardware">Hardware</h3>
 <ul>
-<li><p>$70 - <a href="http://amzn.to/2zggJoh">Raspberry Pi 3</a> (That’s an affiliate link. Here’s <a href="https://www.amazon.com/CanaKit-Raspberry-Complete-Starter-Kit/dp/B0778CZ97B/">one that isn’t</a>). This consumes very little power (a little over 1W without the disks, probably around 10W with them spinning, more like 3W when they are idling), takes up very little space, but seems plenty fast enough to act as a file server. That price includes a case, heat-sink, SD card, power adaptor, etc. If you had any of these things, you can probably get a cheaper kit (the single board itself is around $35). Note that you <em>really</em> want a heat-sink on the processor. I ran without it for a while (forgot to install it) and it would overheat and hard lock. It’s a tradeoff that they put a much faster processor in these than in prior generations – I think it’s worth it (it’s an amazingly capably computer for the size/price).</p></li>
-<li><p>$75 - Three <a href="http://amzn.to/2BluHHj">external USB SATA hard drive enclosures</a>. You might be able to find these cheaper – the ones I got were metal, which seemed good in terms of heat dissipation, and have been running for a little over a year straight without a problem (note: this is actually one more than I’m using at any given time, to make it easier to rotate in new drives; BTRFS, which I’m using, allows you to just physically remove a drive and add a new one, but the preferred method is to have both attached, and issue a <code>replace</code> command. I’m not sure how much this matters, but for $25, I went with the extra enclosure).</p></li>
-<li><p>$170 - Two <a href="http://amzn.to/2C1lc3E">2TB WD Red SATA drives</a>. These are actually recent upgrades – the server was been running on older 1TB Green drives (four and five years old respectively), but one of them started reporting failures (I would speculate the older of the two, but I didn’t check) so I replaced both. The cheaper blue drives probably would have been fine (the Greens that the Blues have replaced certainly have lasted well enough, running nearly 24/7 for years), but the “intended to run 24/7” Red ones were only $20 more each so I thought I might as well spring for them.</p></li>
+<li><p>$70 - Raspberry Pi 3. This consumes very little power (a little over 1W without the disks, probably around 10W with them spinning, more like 3W when they are idling), takes up very little space, but seems plenty fast enough to act as a file server. That price includes a case, heat-sink, SD card, power adaptor, etc. If you had any of these things, you can probably get a cheaper kit (the single board itself is around $35). Note that you <em>really</em> want a heat-sink on the processor. I ran without it for a while (forgot to install it) and it would overheat and hard lock. It’s a tradeoff that they put a much faster processor in these than in prior generations – I think it’s worth it (it’s an amazingly capably computer for the size/price).</p></li>
+<li><p>$75 - Three external USB SATA hard drive enclosures. You might be able to find these cheaper – the ones I got were metal, which seemed good in terms of heat dissipation, and have been running for a little over a year straight without a problem (note: this is actually one more than I’m using at any given time, to make it easier to rotate in new drives; BTRFS, which I’m using, allows you to just physically remove a drive and add a new one, but the preferred method is to have both attached, and issue a <code>replace</code> command. I’m not sure how much this matters, but for $25, I went with the extra enclosure).</p></li>
+<li><p>$170 - Two 2TB WD Red SATA drives. These are actually recent upgrades – the server was been running on older 1TB Green drives (four and five years old respectively), but one of them started reporting failures (I would speculate the older of the two, but I didn’t check) so I replaced both. The cheaper blue drives probably would have been fine (the Greens that the Blues have replaced certainly have lasted well enough, running nearly 24/7 for years), but the “intended to run 24/7” Red ones were only $20 more each so I thought I might as well spring for them.</p></li>
 </ul>
 <h3 id="cloud">Cloud</h3>
 <ul>

essays/2018-01-01-home-backups.markdown

@@ -53,7 +53,7 @@ old one, and once I had it working, there was certainly no point in going back!
 
 ### Hardware
 
-- $70 - [Raspberry Pi 3](http://amzn.to/2zggJoh) (That's an affiliate link. Here's [one that isn't](https://www.amazon.com/CanaKit-Raspberry-Complete-Starter-Kit/dp/B0778CZ97B/)). This consumes very little power (a little over 1W without the disks,
+- $70 - Raspberry Pi 3. This consumes very little power (a little over 1W without the disks,
   probably around 10W with them spinning, more like 3W when they are idling),
   takes up very little space, but seems plenty fast enough to act as a file
   server. That price includes a case, heat-sink, SD card, power adaptor, etc. If
@@ -64,7 +64,7 @@ old one, and once I had it working, there was certainly no point in going back!
   in these than in prior generations -- I think it's worth it (it's an amazingly
   capably computer for the size/price).
 
-- $75 - Three [external USB SATA hard drive enclosures](http://amzn.to/2BluHHj).
+- $75 - Three external USB SATA hard drive enclosures.
   You might be able to find these cheaper -- the ones I got were metal, which
   seemed good in terms of heat dissipation, and have been running for a little
   over a year straight without a problem (note: this is actually one more than
@@ -74,7 +74,7 @@ old one, and once I had it working, there was certainly no point in going back!
   command. I'm not sure how much this matters, but for $25, I went with the
   extra enclosure).
 
-- $170 - Two [2TB WD Red SATA drives](http://amzn.to/2C1lc3E). These are
+- $170 - Two 2TB WD Red SATA drives. These are
   actually recent upgrades -- the server was been running on older 1TB Green
   drives (four and five years old respectively), but one of them started
   reporting failures (I would speculate the older of the two, but I didn't

essays/2018-01-16-how-to-prove-a-compiler-correct.markdown

@@ -390,6 +390,13 @@ error).
 > [here](https://www.cs.uoregon.edu/research/summerschool/summer12/curriculum.html),
 > scroll down to find them).
 
+<br/>
+
+ Thanks to current and former [PRL](http://prl.ccs.neu.edu) members, in
+ particular [Gabriel Scherer](http://gallium.inria.fr/~scherer/) and [William
+ Bowman](https://williamjbowman.com/), for providing useful feedback on drafts
+ of this post.
+
 <br/><br/>
 
 ## Addendum: termination