macOS Sierra升级到macOS High Sierra后执行cc,git等命令报错，错误信息如下：
xcrun: error: invalid active developer path (/Library/Developer/CommandLineTools), missing xcrun at: /Library/Developer/CommandLineTools/usr/bin/xcrun
解决方法如下：
$ xcode-select --install
Windows 7系统上安装CentOS 7后通过修改grub2添加Windows 7启动引导项
按照以往的经验，先安装Windows 7之后，再装CentOS 7,那么CentOS 7应该会自动添加Windows 7启动项。但是安装完成后，发现启动项里没有Windows 7。
我们需要手动添加Windows 7的启动项。
我们需要修改grub2的模版文件，然后执行grub2-mkconfig自动重建grub2引导列表。
$ sudo cp /etc/grub.d/40_custom /etc/grub.d/41_win7_custom
$ sudo vi /etc/grub.d/41_win7_custom
#!/bin/sh
exec tail -n +3 $0
# This file provides an easy way to add custom menu entries. Simply type the
# menu entries you want to add after this comment. Be careful not to change
# the 'exec tail' line above.
menuentry 'Windows 7'{
set root=(hd0,1)
chainloader +1
}
$ grub2-mkconfig -o /boot/grub2/grub.cfg
$ reboot
至于set root=(hd0,1),还是set root=(hd0,msdos1),或者set root=(hd0,msdosX),请在启动列表中按下e键，进入grub rescue模式，执行ls命令列出分区，如果第一个启动不了，请逐个分区都试试。
参考链接
macOS High Sierra (10.13)制作Windows 7安装U盘
- Open a Terminal (under Utilities)
- Convert the ISO to UDRW format
hdiutil convert -format UDRW -o destination_file.img source_file.iso - Run
diskutil listand determine the device node assigned to your flash media (e.g., /dev/disk2) - Run
diskutil unmountDisk /dev/diskN(replace N with the disk number from the last command; in the previous example, N would be 2) - Execute
sudo dd if=/path/to/destination_file.img.dmg of=/dev/diskN bs=1m(replace /path/to/destination_file.img.dmg with the path where the image file is located; for example, ./win7.img.dmg)- Using /dev/rdisk instead of /dev/disk will faster, 20x
- If you see the error dd: Invalid number '1m', you are using GNU dd. Use the same command but replace bs=1m with bs=1M
- If you see the error dd: /dev/diskN: Resource busy, make sure the disk is not in use. Start the 'Disk Utility.app' and unmount (don't eject) the drive
- Run
diskutil eject /dev/diskN, and remove your flash media when the command completes (this can take a few hours on slower drives)
ThinkPad-T440通过U盘启动的方式升级BIOS
最近在ThinkPad-T440上安装最新的Ubuntu 17.04的时候，系统提示如下信息:
Oct 21 00:29:34 ThinkPad-T440 kernel: [ 0.000000] [Firmware Bug]: TSC_DEADLINE disabled due to Errata; please update microcode to version: 0x20 (or later)
通过提示，可以看到是系统的CPU微码部分没有更新到最新，导致系统在执行部分功能的时候发生了异常，升级BIOS可以解决这个问题。
在联想官网上下载最新的BIOS光盘镜像（假定镜像名为BIOSCD.iso）之后，发现无法直接通过U盘启动系统。原因是光盘的镜像格式不符合U盘启动需要的格式，需要进行转换之后才可以正常启动系统。
可以通过如下的方式，转换下载到的镜像文件之后，刷新BIOS。
$ sudo apt-get install genisoimage $ geteltorito -o bios.img BIOSCD.iso #找出U盘挂载的位置，假定是/dev/sdb $ df $ sudo dd if=bios.img of=/dev/sdb
之后，重启系统即可。
WD MyCloud编译PHP-7.1安装包
1.按照How to successfully build packages for WD My Cloud from source中的介绍，搭建完成WDMyCloud的编译环境
2.使用如下方式编译:
$ su $ cd ~/wdmc-build/64k-jessie $ chroot build $ mount -t proc none /proc $ mount -t devtmpfs none /dev $ mount -t devpts none /dev/pts $ export DEBIAN_FRONTEND=noninteractive $ export DEBCONF_NONINTERACTIVE_SEEN=true $ export LC_ALL=C $ export LANGUAGE=C $ export LANG=C $ export DEB_CFLAGS_APPEND='-D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE' $ export DEB_BUILD_OPTIONS=nocheck $ cd root $ apt-get update $ apt-get upgrade $ apt-get install ca-certificates $ apt-get install dh-autoreconf $ apt-get install git $ apt-get install apache2-dev $ apt-get install apache2 $ apt-get install systemtap-sdt-dev $ apt-get install libxml2 $ apt-get install libxml2-dev $ apt-get install libssl-dev $ apt-get install libpcre3 libpcre3-dev $ apt-get install libsqlite3-dev $ apt-get install libbz2-dev $ apt-get install libcurl4-openssl-dev $ apt-get install libqdbm-dev $ apt-get install libdb-dev #configure: error: Cannot find enchant $ apt-get install enchant libenchant-dev #configure: error: webp/decode.h not found $ apt-get install libwebp-dev #configure: error: png.h not found. $ apt-get install libpng-dev #configure: error: xpm.h not found. $ apt-get install libxpm-dev #configure: error: freetype-config not found. $ apt-get install libfreetype6-dev #configure: error: Unable to find gd.h anywhere under /usr $ apt-get install libgd-dev #configure: error: Unable to locate gmp.h $ apt-get install libgmp-dev #configure: error: utf8_mime2text() has new signature, but U8T_CANONICAL is missing. This should not happen. Check config.log for additional information. $ apt-get install libc-client-dev #configure: error: Kerberos libraries not found. $ apt-get install libkrb5-dev #configure: error: libfbclient, libgds or libib_util not found! Check config.log for more information. $ apt-get install firebird-dev #configure: error: Unable to detect ICU prefix or no failed. Please verify ICU install prefix and make sure icu-config works. $ apt-get install libicu-dev #configure: error: sasl.h not found! $ apt-get install libsasl2-dev #configure: error: mcrypt.h not found. Please reinstall libmcrypt. $ apt-get install libmcrypt-dev #checking for unixODBC support... configure: error: ODBC header file '/usr/include/sqlext.h' not found! $ apt-get install unixODBC-dev #configure: error: Directory /usr is not a FreeTDS installation directory $ apt-get install FreeTDS-dev #configure: error: Cannot find libpq-fe.h. Please specify correct PostgreSQL installation path $ apt-get install libpq-dev #configure: error: Cannot find pspell $ apt-get install libpspell-dev #configure: error: Please reinstall libedit - I cannot find readline.h $ apt-get install libedit-dev #configure: error: Can not find recode.h anywhere under /usr /usr/local /usr /opt. $ apt-get install librecode-dev #configure: error: Could not find net-snmp-config binary. Please check your net-snmp installation. $ apt-get install libsnmp-dev #configure: error: Cannot find libtidy $ apt-get install libtidy-dev #checking for XMLRPC-EPI in default path... not found $ apt-get install libxmlrpc-epi-dev #configure: error: xslt-config not found. Please reinstall the libxslt >= 1.1.0 distribution $ apt-get install libxslt-dev #configure: error: Please reinstall the libzip distribution $ apt-get install libzip-dev $ git clone -b master-7.1 https://gitlab.com/deb.sury.org/php.git php7 --depth=1 $ cd php7 #禁用systemd $ sed -i "s/CONFIGURE_SYSTEMD *:= *--with-fpm-systemd/CONFIGURE_SYSTEMD := --without-fpm-systemd/g" debian/rules $ sed -i "s/DH_SYSTEMD *:= *--with systemd/DH_SYSTEMD :=/g" debian/rules $ dpkg-buildpackage -d -b -uc #编译依赖包php-common $ cd .. $ git clone -b debian/50 git://anonscm.debian.org/pkg-php/php-defaults.git $ cd php-defaults #禁用systemd $ sed -i "s/DH_SYSTEMD *:= *--with *systemd/DH_SYSTEMD :=/g" debian/rules $ dpkg-buildpackage -d -b -uc $ exit
3.编译php-apcu,这个模块WD MyCloud需要
$ su $ cd ~/wdmc-build/64k-jessie $ chroot build $ mount -t proc none /proc $ mount -t devtmpfs none /dev $ mount -t devpts none /dev/pts $ export DEBIAN_FRONTEND=noninteractive $ export DEBCONF_NONINTERACTIVE_SEEN=true $ export LC_ALL=C $ export LANGUAGE=C $ export LANG=C $ export DEB_CFLAGS_APPEND='-D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE' $ export DEB_BUILD_OPTIONS=nocheck $ cd root #安装依赖 $ apt-get install shtool $ apt-get install liblist-moreutils-perl $ apt-get install xml2 # "dch" command $ apt-get install devscripts #安装我们刚刚编译好的PHP7包 $ dpkg -i php-common_50_all.deb $ dpkg -i php7.1-common_7.1.10-1_armhf.deb $ dpkg -i php7.1-readline_7.1.10-1_armhf.deb $ dpkg -i php7.1-opcache_7.1.10-1_armhf.deb $ dpkg -i php7.1-json_7.1.10-1_armhf.deb $ dpkg -i php7.1-cli_7.1.10-1_armhf.deb $ dpkg -i php7.1-dev_7.1.10-1_armhf.deb #编译依赖 $ git clone git://anonscm.debian.org/pkg-php/dh-php.git $ cd dh-php $ git checkout debian/0.26 -b debian/0.26 $ dpkg-buildpackage -d -b -uc $ cd .. $ dpkg -i dh-php_0.26_all.deb #参考 https://packages.debian.org/source/sid/php-apcu # git://anonscm.debian.org/pkg-php/php-apcu.git #https://pecl.php.net/package/APCu $ git clone git://anonscm.debian.org/pkg-php/php-apcu.git $ cd php-apcu $ git checkout debian/5.1.8+4.0.11-1 -b debian/5.1.8+4.0.11-1 #Build the package $ debuild -b -d -uc -us $ cd .. $ dpkg -i php-apcu_5.1.8+4.0.11-1_armhf.deb $ git clone git://anonscm.debian.org/pkg-php/php-apcu-bc.git $ cd php-apcu-bc $ debuild -b -d -uc -us $ exit
上面下载的代码由于是国外的服务器，因此可能会出现一直无法下载成功的情况，可以从这里下载代码的拷贝。PHP源代码点击这里，PHP7 Debian编译配置文件点击这里，dh-php源代码点击这里，php-apcu源代码点击这里, php-apcu-bc源代码点击这里。
在WDMyCloud中安装的时候执行如下命令:
$ sudo apt-get update $ sudo apt-get install -y --force-yes php7.1 $ sudo apt-get install -y --force-yes libapache2-mod-php7.1 $ sudo apt-get install -y --force-yes php7.1-curl $ sudo apt-get install -y --force-yes php-apcu $ sudo apt-get install -y --force-yes php-apcu-bc $ sudo apt-get install -y --force-yes php7.1-xml #这个是个坑，如果没有增加这个模块，也是可以正常启动的，但是却没办法正常登录进入，应用会出现异常 $ sudo apt-get install -y --force-yes php7.1-mbstring #由于PHP7中的parse_ini_file不再兼容“#”作为注释字符，只能使用“;”进行注释，但是这个注释无法 #被其他应用读取，而WDMyCloud里面的其他脚本也需要读取/etc/system.conf里面的内容 #目前唯一的解决方法就是删除全部的注释行 # /var/www/htdocs/UI/index.php $ sudo cp /etc/system.conf /etc/system.conf.bak $ sudo sed -i '/^#/d' /etc/system.conf #语法调整 $ sudo cp /var/www/htdocs/UI/views/common/dates.php /var/www/htdocs/UI/views/common/dates.php.bak $ sudo sed -i 's/^<?.*$/<?php/g' /var/www/htdocs/UI/views/common/dates.php #/var/www/htdocs/UI/views/layouts/main/main.php $ sudo cp /etc/php5/apache2/conf.d/include_path.ini /etc/php/7.1/apache2/conf.d/ $ sudo chmod 777 /etc/php/7.1/apache2/conf.d/include_path.ini $ sudo a2dismod php5 $ sudo a2enmod php7.1 $ sudo phpenmod curl $ sudo service apache2 restart
注意，这部分的功能目前仅仅是可用，还没有达到完全正常的情况，如果出现问题，可以切换回PHP5,目前已知的完美切换回到原来的PHP5的办法就是卸载上面安装的所有PHP7的相关应用才能切换成功，否则总有部分小功能不是太正常.
参考链接
神经网络瘦身：SqueezeNet
2016年2月份，UC Berkeley和Stanford一帮人在arXiv贴了一篇文章：
这篇文章做成了许多人梦寐以求的事——压缩神经网络参数。但和以往不同，原作不是在前人网络基础上修修补补（例如Deep Compression），而是自己设计了一个全新的网络，它用了比AlexNet少50倍的参数，达到了AlexNet相同的精度！
关于SqueezeNet的创新点、网络结构，国内已经有若干爱好者发布了相关的简介，如这篇、这篇，国外的文献没有查，相信肯定也有很多。
本文关注的重点在SqueezeNet为什么能实现网络瘦身？难道网络参数的冗余性就那么强吗？或者说很多参数都是浪费的、无意义的？
OpenMediaVault-3.0.89在系统更新升级后无法挂载磁盘
OpenMediaVault-3.0.89在执行应用升级
$ sudo apt-get update $ sudo apt-get upgrade
重启无法自动挂载磁盘,查看系统日志，看到如下内容：
Oct 13 22:53:54 openmediavault systemd[1]: systemd-fsck@dev-disk-by\x2duuid-7909fba8\x2dcc50\x2d430f\x2d986f\x2d9db4ba7caa3c.service: Job systemd-fsck@dev-disk-by\x2duuid-7909fba8\x2dcc50\x2d430f\x2d986f\x2d9db4ba7caa3c.service/start failed with result 'dependency'. Oct 13 22:53:54 openmediavault systemd[1]: dev-disk-by\x2duuid-7909fba8\x2dcc50\x2d430f\x2d986f\x2d9db4ba7caa3c.device: Job dev-disk-by\x2duuid-7909fba8\x2dcc50\x2d430f\x2d986f\x2d9db4ba7caa3c.device/start failed with result 'timeout'. Oct 13 22:54:25 openmediavault monit[1551]: 'collectd' process is not running Oct 13 22:54:25 openmediavault monit[1551]: 'collectd' trying to restart Oct 13 22:54:25 openmediavault monit[1551]: 'collectd' start: '/bin/systemctl start collectd' Oct 13 22:54:55 openmediavault monit[1551]: 'collectd' failed to start (exit status 0) -- no output
这个原因是由于collectd的升级导致了无法使用systemd来启动。而Openmediavaule加载硬盘的时候依赖collectd模块，这个模块的启动问题导致全部磁盘都无法加载。
目前的做法是升级到最新的OpenMediaVault-4.0，参考OpenMediaVault系统升级。
但是升级后会遇到如下错误：
Oct 14 18:01:10 openmediavault collectd[1081]: rrdcached plugin: Failed to connect to RRDCacheD at unix:/var/run/rrdcached.sock: Unable to connect to rrdcached: No such file or directory (status=2)
以及
Oct 14 18:19:28 openmediavault monit[1053]: 'omv-engined' process is not running Oct 14 18:19:28 openmediavault monit[1053]: 'omv-engined' trying to restart Oct 14 18:19:28 openmediavault monit[1053]: 'omv-engined' start: '/bin/systemctl start openmediavault-engined' Oct 14 18:19:59 openmediavault monit[1053]: 'omv-engined' failed to start (exit status 1) -- '/bin/systemctl start openmediavault-engined': Failed to start openmediavault-engined.service: Unit openmediavault-engined.service is masked.
修复方法为：
$ omv-mkconf collectd $ omv-mkconf rrdcached $ omv-mkconf monit $ sudo systemctl unmask openmediavault-engined.service $ sudo reboot
参考链接
ROS Kinetic切换OpenCV到2.X版本
注意，本文章只针对简单的应用，不涉及到复杂的严重依赖OpenCV模块的项目。如果依赖复杂，可能会导致OpenCV 2.X与OpenCV 3.X的运行时库同时被加载，导致运行时候崩溃。
最近在使用ROS开发项目，代码从Indigo(Ubuntu 14.04)升级到Kinetic（Ubuntu 16.04）。
发现OpenCV升级到了opencv-3.2.0-dev版本,但是实际使用中发现代码在opencv-2.4.9版本上能正确运行，但是升级到opencv-3.2.0-dev版本之后，就不能正常工作了。
为了查找问题，需要降级一下OpenCV版本。
网上查找了一下，找到如下解决方法：
$ sudo apt-get install libcv-dev $ sudo apt-get install libopencv-dev $ sudo apt-get install libopencv-contrib-dev $ sudo apt-get install libopencv-gpu-dev $ sudo gedit /opt/ros/kinetic/share/cv_bridge/cmake/cv_bridgeConfig.cmake
然后修改如下的内容(修改之前请注意先备份）
第94-96行：
if(NOT "include;/opt/ros/kinetic/include/opencv-3.1.0-dev/opencv;/opt/ros/kinetic/include/opencv-3.1.0-dev " STREQUAL " ")
set(cv_bridge_INCLUDE_DIRS "")
set(_include_dirs "include;/opt/ros/kinetic/include/opencv-3.1.0-dev/opencv;/opt/ros/kinetic/include/opencv-3.1.0-dev")
#112行：
set(libraries "cv_bridge;/opt/ros/kinetic/lib/libopencv_calib3d3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_core3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_features2d3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_flann3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_highgui3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_imgcodecs3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_imgproc3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_ml3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_objdetect3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_photo3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_shape3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_stitching3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_superres3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_video3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_videoio3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_videostab3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_viz3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_aruco3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_bgsegm3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_bioinspired3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_ccalib3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_cvv3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_datasets3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_dpm3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_face3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_fuzzy3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_hdf3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_line_descriptor3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_optflow3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_phase_unwrapping3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_plot3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_reg3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_rgbd3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_saliency3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_stereo3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_structured_light3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_surface_matching3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_text3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_xfeatures2d3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_ximgproc3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_xobjdetect3.so.3.2.0;/opt/ros/kinetic/lib/libopencv_xphoto3.so.3.2.0")
指向系统自带的opencv-2.4.9版本
#94-96行： if(NOT "include;/usr/include/opencv;/usr/include " STREQUAL " ") set(cv_bridge_INCLUDE_DIRS "") set(_include_dirs "include;/usr/include/opencv;/usr/include") #112行： set(libraries "cv_bridge;/usr/lib/x86_64-linux-gnu/libopencv_calib3d.so;/usr/lib/x86_64-linux-gnu/libopencv_contrib.so;/usr/lib/x86_64-linux-gnu/libopencv_core.so;/usr/lib/x86_64-linux-gnu/libopencv_features2d.so;/usr/lib/x86_64-linux-gnu/libopencv_flann.so;/usr/lib/x86_64-linux-gnu/libopencv_gpu.so;/usr/lib/x86_64-linux-gnu/libopencv_highgui.so;/usr/lib/x86_64-linux-gnu/libopencv_imgproc.so;/usr/lib/x86_64-linux-gnu/libopencv_legacy.so;/usr/lib/x86_64-linux-gnu/libopencv_ml.so;/usr/lib/x86_64-linux-gnu/libopencv_objdetect.so;/usr/lib/x86_64-linux-gnu/libopencv_ocl.so;/usr/lib/x86_64-linux-gnu/libopencv_photo.so;/usr/lib/x86_64-linux-gnu/libopencv_stitching.so;/usr/lib/x86_64-linux-gnu/libopencv_superres.so;/usr/lib/x86_64-linux-gnu/libopencv_ts.so;/usr/lib/x86_64-linux-gnu/libopencv_video.so;/usr/lib/x86_64-linux-gnu/libopencv_videostab.so")
修改完成后，必要的情况下,请在删除~/workspace/ros/catkin/目录下的build，devel目录之后，重新编译。
参考链接
CVR100W升级到最新固件1.0.1.24
家里用的CVR100W路由是几年前买的，当时升级过一次固件，版本到1.0.1.19,但是最近几个月发现出现了无线不稳定的情况，有线访问打开路由器主页也变得比较慢，重启无效。因此怀疑是路由器系统在长时间运行后，这个版本的固件是存在问题的。
去思科官网搜索一下最新固件，竟然看到了1.0.1.24版本的固件，于是下载下来CVR100W_FW_1.0.1.24，各位也可以去思科官网去搜索下载。
目前测试来看，这个版本的固件应该是更稳定，速度也有所提升。
继续阅读CVR100W升级到最新固件1.0.1.24
NVIDIA TX2 (Ubuntu 16.04)上安装CUDA 8.0
使用如下方式安装：
$ cd ~ $ wget http://developer.download.nvidia.com/devzone/devcenter/mobile/jetpack_l4t/013/linux-x64/cuda-repo-l4t-8-0-local_8.0.84-1_arm64.deb $ sudo dpkg -i cuda-repo-l4t-8-0-local_8.0.84-1_arm64.deb $ sudo apt-get update $ sudo apt-get install cuda-toolkit-8-0
至于如何获取最新的NVIDIA TX2上使用的CUDA 8.0版本的下载地址，请访问Jetson Download Center，下载目前最新的JetPack 3.1。执行之后在存储目录下的repository.json中找到最新的下载链接即可。当然也可以让JetPack 3.1自动下载完成最新的CUDA 8.0版本到指定目录。