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    <fireside:genDate>Thu, 30 Apr 2026 20:36:07 -0500</fireside:genDate>
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    <title>TechSNAP - Episodes Tagged with “Kernel Module”</title>
    <link>https://techsnap.systems/tags/kernel%20module</link>
    <pubDate>Fri, 03 Apr 2020 00:15:00 -0700</pubDate>
    <description>Systems, Network, and Administration Podcast. Every two weeks TechSNAP covers the stories that impact those of us in the tech industry, and all of us that follow it. Every episode we dedicate a portion of the show to answer audience questions, discuss best practices, and solving your problems.
</description>
    <language>en-us</language>
    <itunes:type>episodic</itunes:type>
    <itunes:subtitle>Systems, Network, and Administration Podcast. </itunes:subtitle>
    <itunes:author>Jupiter Broadcasting</itunes:author>
    <itunes:summary>Systems, Network, and Administration Podcast. Every two weeks TechSNAP covers the stories that impact those of us in the tech industry, and all of us that follow it. Every episode we dedicate a portion of the show to answer audience questions, discuss best practices, and solving your problems.
</itunes:summary>
    <itunes:image href="https://media24.fireside.fm/file/fireside-images-2024/podcasts/images/9/95197d05-40d6-4e68-8e0b-2f586ce8dc55/cover.jpg?v=4"/>
    <itunes:explicit>no</itunes:explicit>
    <itunes:owner>
      <itunes:name>Jupiter Broadcasting</itunes:name>
      <itunes:email>chris@jupiterbroadcasting.com</itunes:email>
    </itunes:owner>
<itunes:category text="News">
  <itunes:category text="Tech News"/>
</itunes:category>
<item>
  <title>426: Storage Stories</title>
  <link>https://techsnap.systems/426</link>
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  <pubDate>Fri, 03 Apr 2020 00:15:00 -0700</pubDate>
  <author>Jupiter Broadcasting</author>
  <enclosure url="https://aphid.fireside.fm/d/1437767933/95197d05-40d6-4e68-8e0b-2f586ce8dc55/658dd254-b721-4281-8415-9357e180e92b.mp3" length="22528023" type="audio/mp3"/>
  <itunes:episodeType>full</itunes:episodeType>
  <itunes:author>Jupiter Broadcasting</itunes:author>
  <itunes:subtitle>We take a look at Cloudflare's impressive Linux disk encryption speed-ups, and explore how zoned storage tools like dm-zoned and zonefs might help mitigate the downsides of Shingled Magnetic Recording.</itunes:subtitle>
  <itunes:duration>31:17</itunes:duration>
  <itunes:explicit>no</itunes:explicit>
  <itunes:image href="https://media24.fireside.fm/file/fireside-images-2024/podcasts/images/9/95197d05-40d6-4e68-8e0b-2f586ce8dc55/cover.jpg?v=4"/>
  <description>We take a look at Cloudflare's impressive Linux disk encryption speed-ups, and explore how zoned storage tools like dm-zoned and zonefs might help mitigate the downsides of Shingled Magnetic Recording.  
Plus we celebrate WireGuard's inclusion in the Linux 5.6 kernel, and fight some exFAT FUD. 
</description>
  <itunes:keywords>WireGuard, Linux 5.6, kernel module, networking, encryption, security, Ubuntu, Debian, Windows, zonefs, Zoned Storage, SMR, Shingled Magnetic Recording, SSD, NVMe, firmware, block device, dm-zoned, filesystems, device mapper, Western Digital, ZFS, RAID, Seagate, Microsoft, Samsung, Google, Andoird, Paragon Software, exFAT, FUD, open source, free software, NTFS, NTFS-3G, SMB, Samba, Cloudfare, crypto, dm-crypt, DevOps, TechSNAP, Jupiter Broadcasting, A Cloud Guru, sysadmin podcast, </itunes:keywords>
  <content:encoded>
    <![CDATA[<p>We take a look at Cloudflare&#39;s impressive Linux disk encryption speed-ups, and explore how zoned storage tools like dm-zoned and zonefs might help mitigate the downsides of Shingled Magnetic Recording.  </p>

<p>Plus we celebrate WireGuard&#39;s inclusion in the Linux 5.6 kernel, and fight some exFAT FUD.</p><p>Links:</p><ul><li><a title="WireGuard VPN makes it to 1.0.0—and into the next Linux kernel" rel="nofollow" href="https://arstechnica.com/gadgets/2020/03/wireguard-vpn-makes-it-to-1-0-0-and-into-the-next-linux-kernel/">WireGuard VPN makes it to 1.0.0—and into the next Linux kernel</a> &mdash; It's a good day for WireGuard users—DKMS builds will soon be behind us.
</li><li><a title="Linux 5.6 Is The Most Exciting Kernel In Years With So Many New Features" rel="nofollow" href="https://www.phoronix.com/scan.php?page=article&amp;item=linux-56-features&amp;num=1">Linux 5.6 Is The Most Exciting Kernel In Years With So Many New Features</a></li><li><a title="fs: New zonefs file system" rel="nofollow" href="https://lwn.net/Articles/793585/">fs: New zonefs file system</a> &mdash; zonefs is a very simple file system exposing each zone of a zoned block device as a file. This is intended to simplify implementation of application zoned block device raw access support by allowing switching to the well known POSIX file API rather than relying on direct block device file ioctls and read/write.</li><li><a title="Ama-ZNS! Zonefs File-System Will Land with Linux® 5.6" rel="nofollow" href="https://blog.westerndigital.com/zonefs-file-system-linux-5-6/">Ama-ZNS! Zonefs File-System Will Land with Linux® 5.6</a></li><li><a title="What is Zoned Storage and the Zoned Storage Initiative?" rel="nofollow" href="https://blog.westerndigital.com/what-is-zoned-storage-initiative/">What is Zoned Storage and the Zoned Storage Initiative?</a> &mdash; Zoned Storage is a new paradigm in storage motivated by the incredible explosion of data. Our data-driven society is increasingly dependent on data for every-day life and extreme scale data management is becoming a necessity. </li><li><a title="Linux Kernel Support - ZonedStorage.io" rel="nofollow" href="https://www.zonedstorage.io/introduction/linux-support/">Linux Kernel Support - ZonedStorage.io</a></li><li><a title="dm-zoned" rel="nofollow" href="https://www.kernel.org/doc/html/latest/admin-guide/device-mapper/dm-zoned.html">dm-zoned</a> &mdash; The dm-zoned device mapper target exposes a zoned block device as a regular block device.</li><li><a title="Device Mapper - ZonedStorage.io" rel="nofollow" href="https://zonedstorage.io/linux/dm/#dm-zoned">Device Mapper - ZonedStorage.io</a></li><li><a title=" What are PMR and SMR hard disk drives?" rel="nofollow" href="https://www.synology.com/en-us/knowledgebase/DSM/tutorial/Storage/PMR_SMR_hard_disk_drives"> What are PMR and SMR hard disk drives?</a></li><li><a title="Beware of SMR drives in PMR clothing" rel="nofollow" href="https://zfsonlinux.topicbox.com/groups/zfs-discuss/T759a10612888a9d9-Me469c98023e1a2cb059f9391/beware-of-smr-drives-in-pmr-clothing">Beware of SMR drives in PMR clothing</a> &mdash; WD and Seagate are both submarining Drive-managed SMR (DM-SMR) drives into channels, disguised as "normal" drives.</li><li><a title="Beware of SMR drives in PMR clothing [Reddit]" rel="nofollow" href="https://www.reddit.com/r/zfs/comments/frsic7/beware_of_smr_drives_in_pmr_clothing/">Beware of SMR drives in PMR clothing [Reddit]</a></li><li><a title="The exFAT filesystem is coming to Linux—Paragon software’s not happy about it" rel="nofollow" href="https://arstechnica.com/information-technology/2020/03/the-exfat-filesystem-is-coming-to-linux-paragon-softwares-not-happy-about-it/">The exFAT filesystem is coming to Linux—Paragon software’s not happy about it</a> &mdash; When software and operating system giant Microsoft announced its support for inclusion of the exFAT filesystem directly into the Linux kernel back in August, it didn't get a ton of press coverage. But filesystem vendor Paragon Software clearly noticed this month's merge of the Microsoft-approved, largely Samsung-authored version of exFAT into the VFS for-next repository, which will in turn merge into Linux 5.7—and Paragon doesn't seem happy about it.</li><li><a title="The New Microsoft exFAT File-System Driver Is Set To Land With Linux 5.7" rel="nofollow" href="https://www.phoronix.com/scan.php?page=news_item&amp;px=New-exFAT-For-Linux-5.7">The New Microsoft exFAT File-System Driver Is Set To Land With Linux 5.7</a></li><li><a title="Speeding up Linux disk encryption - The Cloudflare Blog" rel="nofollow" href="https://blog.cloudflare.com/speeding-up-linux-disk-encryption/">Speeding up Linux disk encryption - The Cloudflare Blog</a> &mdash; Encrypting data at rest is vital for Cloudflare with more than 200 data centres across the world. In this post, we will investigate the performance of disk encryption on Linux and explain how we made it at least two times faster for ourselves and our customers.</li><li><a title="Add inline dm-crypt patch and xtsproxy Crypto API patch" rel="nofollow" href="https://github.com/cloudflare/linux/blob/master/patches/0023-Add-DM_CRYPT_FORCE_INLINE-flag-to-dm-crypt-target.patch">Add inline dm-crypt patch and xtsproxy Crypto API patch</a></li></ul>]]>
  </content:encoded>
  <itunes:summary>
    <![CDATA[<p>We take a look at Cloudflare&#39;s impressive Linux disk encryption speed-ups, and explore how zoned storage tools like dm-zoned and zonefs might help mitigate the downsides of Shingled Magnetic Recording.  </p>

<p>Plus we celebrate WireGuard&#39;s inclusion in the Linux 5.6 kernel, and fight some exFAT FUD.</p><p>Links:</p><ul><li><a title="WireGuard VPN makes it to 1.0.0—and into the next Linux kernel" rel="nofollow" href="https://arstechnica.com/gadgets/2020/03/wireguard-vpn-makes-it-to-1-0-0-and-into-the-next-linux-kernel/">WireGuard VPN makes it to 1.0.0—and into the next Linux kernel</a> &mdash; It's a good day for WireGuard users—DKMS builds will soon be behind us.
</li><li><a title="Linux 5.6 Is The Most Exciting Kernel In Years With So Many New Features" rel="nofollow" href="https://www.phoronix.com/scan.php?page=article&amp;item=linux-56-features&amp;num=1">Linux 5.6 Is The Most Exciting Kernel In Years With So Many New Features</a></li><li><a title="fs: New zonefs file system" rel="nofollow" href="https://lwn.net/Articles/793585/">fs: New zonefs file system</a> &mdash; zonefs is a very simple file system exposing each zone of a zoned block device as a file. This is intended to simplify implementation of application zoned block device raw access support by allowing switching to the well known POSIX file API rather than relying on direct block device file ioctls and read/write.</li><li><a title="Ama-ZNS! Zonefs File-System Will Land with Linux® 5.6" rel="nofollow" href="https://blog.westerndigital.com/zonefs-file-system-linux-5-6/">Ama-ZNS! Zonefs File-System Will Land with Linux® 5.6</a></li><li><a title="What is Zoned Storage and the Zoned Storage Initiative?" rel="nofollow" href="https://blog.westerndigital.com/what-is-zoned-storage-initiative/">What is Zoned Storage and the Zoned Storage Initiative?</a> &mdash; Zoned Storage is a new paradigm in storage motivated by the incredible explosion of data. Our data-driven society is increasingly dependent on data for every-day life and extreme scale data management is becoming a necessity. </li><li><a title="Linux Kernel Support - ZonedStorage.io" rel="nofollow" href="https://www.zonedstorage.io/introduction/linux-support/">Linux Kernel Support - ZonedStorage.io</a></li><li><a title="dm-zoned" rel="nofollow" href="https://www.kernel.org/doc/html/latest/admin-guide/device-mapper/dm-zoned.html">dm-zoned</a> &mdash; The dm-zoned device mapper target exposes a zoned block device as a regular block device.</li><li><a title="Device Mapper - ZonedStorage.io" rel="nofollow" href="https://zonedstorage.io/linux/dm/#dm-zoned">Device Mapper - ZonedStorage.io</a></li><li><a title=" What are PMR and SMR hard disk drives?" rel="nofollow" href="https://www.synology.com/en-us/knowledgebase/DSM/tutorial/Storage/PMR_SMR_hard_disk_drives"> What are PMR and SMR hard disk drives?</a></li><li><a title="Beware of SMR drives in PMR clothing" rel="nofollow" href="https://zfsonlinux.topicbox.com/groups/zfs-discuss/T759a10612888a9d9-Me469c98023e1a2cb059f9391/beware-of-smr-drives-in-pmr-clothing">Beware of SMR drives in PMR clothing</a> &mdash; WD and Seagate are both submarining Drive-managed SMR (DM-SMR) drives into channels, disguised as "normal" drives.</li><li><a title="Beware of SMR drives in PMR clothing [Reddit]" rel="nofollow" href="https://www.reddit.com/r/zfs/comments/frsic7/beware_of_smr_drives_in_pmr_clothing/">Beware of SMR drives in PMR clothing [Reddit]</a></li><li><a title="The exFAT filesystem is coming to Linux—Paragon software’s not happy about it" rel="nofollow" href="https://arstechnica.com/information-technology/2020/03/the-exfat-filesystem-is-coming-to-linux-paragon-softwares-not-happy-about-it/">The exFAT filesystem is coming to Linux—Paragon software’s not happy about it</a> &mdash; When software and operating system giant Microsoft announced its support for inclusion of the exFAT filesystem directly into the Linux kernel back in August, it didn't get a ton of press coverage. But filesystem vendor Paragon Software clearly noticed this month's merge of the Microsoft-approved, largely Samsung-authored version of exFAT into the VFS for-next repository, which will in turn merge into Linux 5.7—and Paragon doesn't seem happy about it.</li><li><a title="The New Microsoft exFAT File-System Driver Is Set To Land With Linux 5.7" rel="nofollow" href="https://www.phoronix.com/scan.php?page=news_item&amp;px=New-exFAT-For-Linux-5.7">The New Microsoft exFAT File-System Driver Is Set To Land With Linux 5.7</a></li><li><a title="Speeding up Linux disk encryption - The Cloudflare Blog" rel="nofollow" href="https://blog.cloudflare.com/speeding-up-linux-disk-encryption/">Speeding up Linux disk encryption - The Cloudflare Blog</a> &mdash; Encrypting data at rest is vital for Cloudflare with more than 200 data centres across the world. In this post, we will investigate the performance of disk encryption on Linux and explain how we made it at least two times faster for ourselves and our customers.</li><li><a title="Add inline dm-crypt patch and xtsproxy Crypto API patch" rel="nofollow" href="https://github.com/cloudflare/linux/blob/master/patches/0023-Add-DM_CRYPT_FORCE_INLINE-flag-to-dm-crypt-target.patch">Add inline dm-crypt patch and xtsproxy Crypto API patch</a></li></ul>]]>
  </itunes:summary>
</item>
<item>
  <title>408: Apollo's ARC</title>
  <link>https://techsnap.systems/408</link>
  <guid isPermaLink="false">2577b50c-e740-46c8-a75b-14f074cb812a</guid>
  <pubDate>Fri, 26 Jul 2019 00:15:00 -0700</pubDate>
  <author>Jupiter Broadcasting</author>
  <enclosure url="https://aphid.fireside.fm/d/1437767933/95197d05-40d6-4e68-8e0b-2f586ce8dc55/2577b50c-e740-46c8-a75b-14f074cb812a.mp3" length="25365234" type="audio/mp3"/>
  <itunes:episodeType>full</itunes:episodeType>
  <itunes:author>Jupiter Broadcasting</itunes:author>
  <itunes:subtitle>We take a look at the amazing abilities of the Apollo Guidance Computer and Jim breaks down everything you need to know about the ZFS ARC.</itunes:subtitle>
  <itunes:duration>35:13</itunes:duration>
  <itunes:explicit>no</itunes:explicit>
  <itunes:image href="https://media24.fireside.fm/file/fireside-images-2024/podcasts/images/9/95197d05-40d6-4e68-8e0b-2f586ce8dc55/cover.jpg?v=4"/>
  <description>We take a look at the amazing abilities of the Apollo Guidance Computer and Jim breaks down everything you need to know about the ZFS ARC. 
Plus an update on ZoL SIMD acceleration, your feedback, and an interesting new neuromorphic system from Intel. 
</description>
  <itunes:keywords>virtualization, openzfs, zfs, kvm, qemu, vhd, qcow, qcow2, ARC, memory, page cache, caching, ZFS on Linux, ZoL, SIMD, floating point, fpu, apollo, apollo anniversary, nasa, retro computing, magnetic core, core rope, AGC, apollo guidance computer, intel, dancing demon, kernel module, loihi, neuromorphic computing, text adventure, punch cards, Margaret Hamilton, neural networks, machine learning, ai, pohoiki, snapshots, sysadmin, trs-80, cloud, Chris Siebenmann,  DevOps, TechSNAP</itunes:keywords>
  <content:encoded>
    <![CDATA[<p>We take a look at the amazing abilities of the Apollo Guidance Computer and Jim breaks down everything you need to know about the ZFS ARC. </p>

<p>Plus an update on ZoL SIMD acceleration, your feedback, and an interesting new neuromorphic system from Intel.</p><p>Links:</p><ul><li><a title="ZFS On Linux Has Figured Out A Way To Restore SIMD Support On Linux 5.0+" rel="nofollow" href="https://www.phoronix.com/scan.php?page=news_item&amp;px=ZFS-On-Linux-Restoring-SIMD">ZFS On Linux Has Figured Out A Way To Restore SIMD Support On Linux 5.0+</a> &mdash; Those running ZFS On Linux (ZoL) on post-5.0 (and pre-5.0 supported LTS releases) have seen big performance hits to the ZFS encryption performance in particular. That came due to upstream breaking an interface used by ZFS On Linux and admittedly not caring about ZoL due to it being an out-of-tree user. But now several kernel releases later, a workaround has been devised. </li><li><a title="ZFS On Linux Runs Into A Snag With Linux 5.0" rel="nofollow" href="https://www.phoronix.com/scan.php?page=news_item&amp;px=ZFS-On-Linux-5.0-Problem">ZFS On Linux Runs Into A Snag With Linux 5.0</a></li><li><a title="NixOS Takes Action After 1.2GB/s ZFS Encryption Speed Drops To 200MB/s With Linux 5.0+" rel="nofollow" href="https://www.phoronix.com/scan.php?page=news_item&amp;px=NixOS-Linux-5.0-ZFS-FPU-Drop">NixOS Takes Action After 1.2GB/s ZFS Encryption Speed Drops To 200MB/s With Linux 5.0+</a> &mdash;  A NixOS developer reports that the functions no longer exported by Linux 5.0+ and previously used by ZoL for AVX/AES-NI support end up dropping the ZFS data-set encryption performance to 200MB/s where as pre-5.0 kernels ran around 1.2GB/s</li><li><a title="Linux 5.0 compat: SIMD compatibility · zfsonlinux/zfs@e5db313" rel="nofollow" href="https://github.com/zfsonlinux/zfs/commit/e5db31349484e5e859c7a942eb15b98d68ce5b4d">Linux 5.0 compat: SIMD compatibility · zfsonlinux/zfs@e5db313</a> &mdash; Restore the SIMD optimization for 4.19.38 LTS, 4.14.120 LTS,
and 5.0 and newer kernels.  This is accomplished by leveraging
the fact that by definition dedicated kernel threads never need
to concern themselves with saving and restoring the user FPU state.
Therefore, they may use the FPU as long as we can guarantee user
tasks always restore their FPU state before context switching back
to user space.</li><li><a title="no SIMD acceleration · Issue #8793 · zfsonlinux/zfs" rel="nofollow" href="https://github.com/zfsonlinux/zfs/issues/8793">no SIMD acceleration · Issue #8793 · zfsonlinux/zfs</a> &mdash; 4.14.x, 4.19.x, 5.x all have no SIMD acceleration, it is like a turtle. very slow.

</li><li><a title="Chris&#39;s Wiki :: ZFS on Linux still has annoying issues with ARC size" rel="nofollow" href="https://utcc.utoronto.ca/~cks/space/blog/linux/ZFSOnLinuxARCShrinkage">Chris's Wiki :: ZFS on Linux still has annoying issues with ARC size</a> &mdash; One of the frustrating things about operating ZFS on Linux is that the ARC size is critical but ZFS's auto-tuning of it is opaque and apparently prone to malfunctions, where your ARC will mysteriously shrink drastically and then stick there.
</li><li><a title="Software woven into wire, Core rope and the Apollo Guidance Computer" rel="nofollow" href="http://www.righto.com/2019/07/software-woven-into-wire-core-rope-and.html">Software woven into wire, Core rope and the Apollo Guidance Computer</a> &mdash; One of the first computers to use integrated circuits, the Apollo Guidance Computer was lightweight enough and small enough to fly in space. An unusual feature that contributed to its small size was core rope memory, a technique of physically weaving software into high-density storage.</li><li><a title="Virtual Apollo Guidance Computer (AGC) software" rel="nofollow" href="https://github.com/virtualagc/virtualagc">Virtual Apollo Guidance Computer (AGC) software</a> &mdash; Since you are looking at this README file, you are in the "master" branch of the repository, which contains source-code transcriptions of the original Project Apollo software for the Apollo Guidance Computer (AGC) and Abort Guidance System (AGS), as well as our software for emulating the AGC, AGS, and some of their peripheral devices (such as the display-keyboard unit, or DSKY).</li><li><a title="The Underappreciated Power of the Apollo Computer - The Atlantic" rel="nofollow" href="https://www.theatlantic.com/science/archive/2019/07/underappreciated-power-apollo-computer/594121/">The Underappreciated Power of the Apollo Computer - The Atlantic</a> &mdash; Without the computers on board the Apollo spacecraft, there would have been no moon landing, no triumphant first step, no high-water mark for human space travel. A pilot could never have navigated the way to the moon, as if a spaceship were simply a more powerful airplane. The calculations required to make in-flight adjustments and the complexity of the thrust controls outstripped human capacities.</li><li><a title="Brains scale better than CPUs. So Intel is building brains | Ars Technica" rel="nofollow" href="https://arstechnica.com/science/2019/07/brains-scale-better-than-cpus-so-intel-is-building-brains/">Brains scale better than CPUs. So Intel is building brains | Ars Technica</a> &mdash; Neuromorphic engineering—building machines that mimic the function of organic brains in hardware as well as software—is becoming more and more prominent. The field has progressed rapidly, from conceptual beginnings in the late 1980s to&nbsp;experimental field programmable neural arrays in 2006, early memristor-powered device proposals in 2012, IBM's TrueNorth NPU in 2014, and Intel's Loihi neuromorphic processor in 2017. Yesterday, Intel broke a little more new ground with the debut of a larger-scale neuromorphic system, Pohoiki Beach, which integrates 64 of its Loihi chips.
</li><li><a title="Dancing Demon - YouTube" rel="nofollow" href="https://www.youtube.com/watch?v=6CCJFQ_bP0E">Dancing Demon - YouTube</a> &mdash; Written in 1979 by Leo Christopherson for the Radio Shack TRS-80 Model I computer. This is the best game ever for at that time.</li></ul>]]>
  </content:encoded>
  <itunes:summary>
    <![CDATA[<p>We take a look at the amazing abilities of the Apollo Guidance Computer and Jim breaks down everything you need to know about the ZFS ARC. </p>

<p>Plus an update on ZoL SIMD acceleration, your feedback, and an interesting new neuromorphic system from Intel.</p><p>Links:</p><ul><li><a title="ZFS On Linux Has Figured Out A Way To Restore SIMD Support On Linux 5.0+" rel="nofollow" href="https://www.phoronix.com/scan.php?page=news_item&amp;px=ZFS-On-Linux-Restoring-SIMD">ZFS On Linux Has Figured Out A Way To Restore SIMD Support On Linux 5.0+</a> &mdash; Those running ZFS On Linux (ZoL) on post-5.0 (and pre-5.0 supported LTS releases) have seen big performance hits to the ZFS encryption performance in particular. That came due to upstream breaking an interface used by ZFS On Linux and admittedly not caring about ZoL due to it being an out-of-tree user. But now several kernel releases later, a workaround has been devised. </li><li><a title="ZFS On Linux Runs Into A Snag With Linux 5.0" rel="nofollow" href="https://www.phoronix.com/scan.php?page=news_item&amp;px=ZFS-On-Linux-5.0-Problem">ZFS On Linux Runs Into A Snag With Linux 5.0</a></li><li><a title="NixOS Takes Action After 1.2GB/s ZFS Encryption Speed Drops To 200MB/s With Linux 5.0+" rel="nofollow" href="https://www.phoronix.com/scan.php?page=news_item&amp;px=NixOS-Linux-5.0-ZFS-FPU-Drop">NixOS Takes Action After 1.2GB/s ZFS Encryption Speed Drops To 200MB/s With Linux 5.0+</a> &mdash;  A NixOS developer reports that the functions no longer exported by Linux 5.0+ and previously used by ZoL for AVX/AES-NI support end up dropping the ZFS data-set encryption performance to 200MB/s where as pre-5.0 kernels ran around 1.2GB/s</li><li><a title="Linux 5.0 compat: SIMD compatibility · zfsonlinux/zfs@e5db313" rel="nofollow" href="https://github.com/zfsonlinux/zfs/commit/e5db31349484e5e859c7a942eb15b98d68ce5b4d">Linux 5.0 compat: SIMD compatibility · zfsonlinux/zfs@e5db313</a> &mdash; Restore the SIMD optimization for 4.19.38 LTS, 4.14.120 LTS,
and 5.0 and newer kernels.  This is accomplished by leveraging
the fact that by definition dedicated kernel threads never need
to concern themselves with saving and restoring the user FPU state.
Therefore, they may use the FPU as long as we can guarantee user
tasks always restore their FPU state before context switching back
to user space.</li><li><a title="no SIMD acceleration · Issue #8793 · zfsonlinux/zfs" rel="nofollow" href="https://github.com/zfsonlinux/zfs/issues/8793">no SIMD acceleration · Issue #8793 · zfsonlinux/zfs</a> &mdash; 4.14.x, 4.19.x, 5.x all have no SIMD acceleration, it is like a turtle. very slow.

</li><li><a title="Chris&#39;s Wiki :: ZFS on Linux still has annoying issues with ARC size" rel="nofollow" href="https://utcc.utoronto.ca/~cks/space/blog/linux/ZFSOnLinuxARCShrinkage">Chris's Wiki :: ZFS on Linux still has annoying issues with ARC size</a> &mdash; One of the frustrating things about operating ZFS on Linux is that the ARC size is critical but ZFS's auto-tuning of it is opaque and apparently prone to malfunctions, where your ARC will mysteriously shrink drastically and then stick there.
</li><li><a title="Software woven into wire, Core rope and the Apollo Guidance Computer" rel="nofollow" href="http://www.righto.com/2019/07/software-woven-into-wire-core-rope-and.html">Software woven into wire, Core rope and the Apollo Guidance Computer</a> &mdash; One of the first computers to use integrated circuits, the Apollo Guidance Computer was lightweight enough and small enough to fly in space. An unusual feature that contributed to its small size was core rope memory, a technique of physically weaving software into high-density storage.</li><li><a title="Virtual Apollo Guidance Computer (AGC) software" rel="nofollow" href="https://github.com/virtualagc/virtualagc">Virtual Apollo Guidance Computer (AGC) software</a> &mdash; Since you are looking at this README file, you are in the "master" branch of the repository, which contains source-code transcriptions of the original Project Apollo software for the Apollo Guidance Computer (AGC) and Abort Guidance System (AGS), as well as our software for emulating the AGC, AGS, and some of their peripheral devices (such as the display-keyboard unit, or DSKY).</li><li><a title="The Underappreciated Power of the Apollo Computer - The Atlantic" rel="nofollow" href="https://www.theatlantic.com/science/archive/2019/07/underappreciated-power-apollo-computer/594121/">The Underappreciated Power of the Apollo Computer - The Atlantic</a> &mdash; Without the computers on board the Apollo spacecraft, there would have been no moon landing, no triumphant first step, no high-water mark for human space travel. A pilot could never have navigated the way to the moon, as if a spaceship were simply a more powerful airplane. The calculations required to make in-flight adjustments and the complexity of the thrust controls outstripped human capacities.</li><li><a title="Brains scale better than CPUs. So Intel is building brains | Ars Technica" rel="nofollow" href="https://arstechnica.com/science/2019/07/brains-scale-better-than-cpus-so-intel-is-building-brains/">Brains scale better than CPUs. So Intel is building brains | Ars Technica</a> &mdash; Neuromorphic engineering—building machines that mimic the function of organic brains in hardware as well as software—is becoming more and more prominent. The field has progressed rapidly, from conceptual beginnings in the late 1980s to&nbsp;experimental field programmable neural arrays in 2006, early memristor-powered device proposals in 2012, IBM's TrueNorth NPU in 2014, and Intel's Loihi neuromorphic processor in 2017. Yesterday, Intel broke a little more new ground with the debut of a larger-scale neuromorphic system, Pohoiki Beach, which integrates 64 of its Loihi chips.
</li><li><a title="Dancing Demon - YouTube" rel="nofollow" href="https://www.youtube.com/watch?v=6CCJFQ_bP0E">Dancing Demon - YouTube</a> &mdash; Written in 1979 by Leo Christopherson for the Radio Shack TRS-80 Model I computer. This is the best game ever for at that time.</li></ul>]]>
  </itunes:summary>
</item>
<item>
  <title>396: Floating Point Problems</title>
  <link>https://techsnap.systems/396</link>
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  <pubDate>Thu, 31 Jan 2019 20:45:00 -0800</pubDate>
  <author>Jupiter Broadcasting</author>
  <enclosure url="https://aphid.fireside.fm/d/1437767933/95197d05-40d6-4e68-8e0b-2f586ce8dc55/bc968a3f-c804-4203-ae2b-dc43ef919218.mp3" length="19582037" type="audio/mp3"/>
  <itunes:episodeType>full</itunes:episodeType>
  <itunes:author>Jupiter Broadcasting</itunes:author>
  <itunes:subtitle>Jim and Wes are joined by OpenZFS developer Richard Yao to explain why the recent drama over Linux kernel 5.0 is no big deal, and how his fix for the underlying issue might actually make things faster.</itunes:subtitle>
  <itunes:duration>27:11</itunes:duration>
  <itunes:explicit>no</itunes:explicit>
  <itunes:image href="https://media24.fireside.fm/file/fireside-images-2024/podcasts/images/9/95197d05-40d6-4e68-8e0b-2f586ce8dc55/cover.jpg?v=4"/>
  <description>Jim and Wes are joined by OpenZFS developer Richard Yao to explain why the recent drama over Linux kernel 5.0 is no big deal, and how his fix for the underlying issue might actually make things faster.
Plus the nitty-gritty details of vectorized optimizations and kernel preemption, and our thoughts on the future of the relationship between ZFS and Linux. Special Guest: Richard Yao.
</description>
  <itunes:keywords>GPL, CDDL, Oracle, FPU, SIMD, vectorized instructions, AVX, hardware acceleration, journaling, data integrity, LFNW, floating point, checksum, snapshot, clone, FreeBSD, kernel module, header, software license, Linux, Multitasking, kernel preemption, OpenZFS, ZFS, ZoL, ZFS on Linux, Storage, RAID, ZVOL, SysAdmin podcast, DevOps, TechSNAP</itunes:keywords>
  <content:encoded>
    <![CDATA[<p>Jim and Wes are joined by OpenZFS developer Richard Yao to explain why the recent drama over Linux kernel 5.0 is no big deal, and how his fix for the underlying issue might actually make things faster.</p>

<p>Plus the nitty-gritty details of vectorized optimizations and kernel preemption, and our thoughts on the future of the relationship between ZFS and Linux.</p><p>Special Guest: Richard Yao.</p><p>Links:</p><ul><li><a title="LinuxFest Northwest 2019" rel="nofollow" href="https://linuxfestnorthwest.org/conferences/2019">LinuxFest Northwest 2019</a> &mdash; Join a bunch of JB hosts and community celebrating the 20th anniversary! </li><li><a title="Choose Linux" rel="nofollow" href="https://chooselinux.show/">Choose Linux</a> &mdash; The show that captures the excitement of discovering Linux.</li><li><a title="Linux 5.0: _kernel_fpu{begin,end} no longer exported" rel="nofollow" href="https://github.com/zfsonlinux/zfs/issues/8259">Linux 5.0: _kernel_fpu{begin,end} no longer exported</a> &mdash; The latest kernels removed the old compatibility headers.</li><li><a title="ZFS On Linux Landing Workaround For Linux 5.0 Kernel Support" rel="nofollow" href="https://www.phoronix.com/scan.php?page=news_item&amp;px=ZFS-On-Linux-5.0-Workaround">ZFS On Linux Landing Workaround For Linux 5.0 Kernel Support</a> &mdash; So while these symbols are important for SIMD vectorized checksums for ZFS in the name of performance, with Linux 5.0+ they are not going to be exported for use by non-GPL modules. ZFS On Linux developer Tony Hutter has now staged a change that would disable vector instructions on Linux 5.0+ kernels.</li><li><a title="Re: x86/fpu: Don&#39;t export __kernel_fpu_{begin,end}()" rel="nofollow" href="https://marc.info/?l=linux-kernel&amp;m=154714516832389">Re: x86/fpu: Don't export __kernel_fpu_{begin,end}()</a> &mdash; My tolerance for ZFS is pretty non-existant.  Sun explicitly did not want their code to work on Linux, so why would we do extra work to get their code to work properly?</li><li><a title="The future of ZFS in FreeBSD" rel="nofollow" href="https://lists.freebsd.org/pipermail/freebsd-current/2018-December/072422.html">The future of ZFS in FreeBSD</a> &mdash; This state of affairs has led to a general agreement among the stakeholders that I have spoken to that it makes sense to rebase FreeBSD's ZFS on ZoL. Brian Behlendorf has graciously encouraged me to add FreeBSD support directly so that we might all have a singleshared code base.</li><li><a title="Dephix: Kickoff to The Future" rel="nofollow" href="https://www.delphix.com/blog/kickoff-future-eko-2018">Dephix: Kickoff to The Future</a> &mdash; OpenZFS has grown over the last decade, and delivering our application on Linux provides great OpenZFS support while enabling higher velocity adoption of new environments.</li><li><a title="The future of ZFS on Linux [zfs-discuss] " rel="nofollow" href="http://list.zfsonlinux.org/pipermail/zfs-discuss/2019-January/033300.html">The future of ZFS on Linux [zfs-discuss] </a> &mdash; 
Do you realize that we don’t actually need the symbols that the kernel removed. It All they do is save/restore of register state while turning off/on preemption. Nothing stops us from doing that ourselves. It is possible to implement our own substitutes using code from either Illumos or FreeBSD or even write our own. 

Honestly, I am beginning to think that my attempt to compromise with mainline gave the wrong impression. I am simply tired of this behavior by them and felt like reaching out to put an end to it. In a few weeks, we will likely be running on Linux 5.0 as if those symbols had never been removed because we will almost certainly have our own substitutes for them. Having to bloat our code because mainline won’t give us access to trivial functionality is annoying, but it is not the end of the world.</li><li><a title="LINUX Unplugged Episode 284: Free as in Get Out" rel="nofollow" href="https://linuxunplugged.com/284">LINUX Unplugged Episode 284: Free as in Get Out</a></li><li><a title="BSD Now 279: Future of ZFS" rel="nofollow" href="https://www.bsdnow.tv/episodes/2019_01_02-future_of_zfs">BSD Now 279: Future of ZFS</a></li><li><a title="BSD Now 157: ZFS, The “Universal” File-system" rel="nofollow" href="https://www.bsdnow.tv/episodes/2016_08_31-the_universal_filesystem">BSD Now 157: ZFS, The “Universal” File-system</a></li></ul>]]>
  </content:encoded>
  <itunes:summary>
    <![CDATA[<p>Jim and Wes are joined by OpenZFS developer Richard Yao to explain why the recent drama over Linux kernel 5.0 is no big deal, and how his fix for the underlying issue might actually make things faster.</p>

<p>Plus the nitty-gritty details of vectorized optimizations and kernel preemption, and our thoughts on the future of the relationship between ZFS and Linux.</p><p>Special Guest: Richard Yao.</p><p>Links:</p><ul><li><a title="LinuxFest Northwest 2019" rel="nofollow" href="https://linuxfestnorthwest.org/conferences/2019">LinuxFest Northwest 2019</a> &mdash; Join a bunch of JB hosts and community celebrating the 20th anniversary! </li><li><a title="Choose Linux" rel="nofollow" href="https://chooselinux.show/">Choose Linux</a> &mdash; The show that captures the excitement of discovering Linux.</li><li><a title="Linux 5.0: _kernel_fpu{begin,end} no longer exported" rel="nofollow" href="https://github.com/zfsonlinux/zfs/issues/8259">Linux 5.0: _kernel_fpu{begin,end} no longer exported</a> &mdash; The latest kernels removed the old compatibility headers.</li><li><a title="ZFS On Linux Landing Workaround For Linux 5.0 Kernel Support" rel="nofollow" href="https://www.phoronix.com/scan.php?page=news_item&amp;px=ZFS-On-Linux-5.0-Workaround">ZFS On Linux Landing Workaround For Linux 5.0 Kernel Support</a> &mdash; So while these symbols are important for SIMD vectorized checksums for ZFS in the name of performance, with Linux 5.0+ they are not going to be exported for use by non-GPL modules. ZFS On Linux developer Tony Hutter has now staged a change that would disable vector instructions on Linux 5.0+ kernels.</li><li><a title="Re: x86/fpu: Don&#39;t export __kernel_fpu_{begin,end}()" rel="nofollow" href="https://marc.info/?l=linux-kernel&amp;m=154714516832389">Re: x86/fpu: Don't export __kernel_fpu_{begin,end}()</a> &mdash; My tolerance for ZFS is pretty non-existant.  Sun explicitly did not want their code to work on Linux, so why would we do extra work to get their code to work properly?</li><li><a title="The future of ZFS in FreeBSD" rel="nofollow" href="https://lists.freebsd.org/pipermail/freebsd-current/2018-December/072422.html">The future of ZFS in FreeBSD</a> &mdash; This state of affairs has led to a general agreement among the stakeholders that I have spoken to that it makes sense to rebase FreeBSD's ZFS on ZoL. Brian Behlendorf has graciously encouraged me to add FreeBSD support directly so that we might all have a singleshared code base.</li><li><a title="Dephix: Kickoff to The Future" rel="nofollow" href="https://www.delphix.com/blog/kickoff-future-eko-2018">Dephix: Kickoff to The Future</a> &mdash; OpenZFS has grown over the last decade, and delivering our application on Linux provides great OpenZFS support while enabling higher velocity adoption of new environments.</li><li><a title="The future of ZFS on Linux [zfs-discuss] " rel="nofollow" href="http://list.zfsonlinux.org/pipermail/zfs-discuss/2019-January/033300.html">The future of ZFS on Linux [zfs-discuss] </a> &mdash; 
Do you realize that we don’t actually need the symbols that the kernel removed. It All they do is save/restore of register state while turning off/on preemption. Nothing stops us from doing that ourselves. It is possible to implement our own substitutes using code from either Illumos or FreeBSD or even write our own. 

Honestly, I am beginning to think that my attempt to compromise with mainline gave the wrong impression. I am simply tired of this behavior by them and felt like reaching out to put an end to it. In a few weeks, we will likely be running on Linux 5.0 as if those symbols had never been removed because we will almost certainly have our own substitutes for them. Having to bloat our code because mainline won’t give us access to trivial functionality is annoying, but it is not the end of the world.</li><li><a title="LINUX Unplugged Episode 284: Free as in Get Out" rel="nofollow" href="https://linuxunplugged.com/284">LINUX Unplugged Episode 284: Free as in Get Out</a></li><li><a title="BSD Now 279: Future of ZFS" rel="nofollow" href="https://www.bsdnow.tv/episodes/2019_01_02-future_of_zfs">BSD Now 279: Future of ZFS</a></li><li><a title="BSD Now 157: ZFS, The “Universal” File-system" rel="nofollow" href="https://www.bsdnow.tv/episodes/2016_08_31-the_universal_filesystem">BSD Now 157: ZFS, The “Universal” File-system</a></li></ul>]]>
  </itunes:summary>
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