Xcode 窗口 Debug 区域显示的Log 仅显示由 Xcode 唤起进程的打印输出。 对于App Extension 工程，进程是由系统唤起的，而不是由 Xcode 。所有开发调试时无法查看到NSLog等打印的输出。

一般可以通过 Console （控制台） 程序来显示这些输出。

MacOS 升级 Catalina 后,打开Adobe Air出现错误：“Adobe AIR.framework” is damaged and can’t be opened.

可以通过如下方式移除安全隔离属性

cd /Library/Frameworks
sudo xattr -r -d com.apple.quarantine ./Adobe\ AIR.framework

Electron 安装常见错误和解决方法。

1. 自定义镜像 ELECTRON_MIRROR=https://npm.taobao.org/mirrors/electron/ npm –registry=https://registry.npm.taobao.org install electron@5.0.13
2. –unsafe-perm=true

Instagram 的名称取自"即时"（英语：instant ）与“电报”（英语：telegram ）两个单词的结合。因为创始人灵感来自即时成像相机，且认为人与人之间的照片分享“就像用电线传递电报消息”，因而将两个单词结合成软件名称

原理

使用 orm.RegisterDataBase 注册多个数据库，其中一个为default，且为主库.

ORM must register a database with alias default.

Employees and students often need to create attractive documents for presentations and text documents. Popular commercial software for creating great-looking documents includes PowerPoint, Keynote and Pages. PowerPoint is a Microsoft product, while Apple makes Keynote and Pages. While there are similarities between the three programs, there are also major differences. Choosing between the three when creating a document depends on your needs.

https://gist.github.com/jboner/2841832

Latency Comparison Numbers (~2012)

DSP：需求方平台 (demand-side platform)

A demand-side platform (DSP) allows buyers of digital ad inventory to manage multiple ad exchanges via one interface. These buyers commonly include trading desks, agencies, or advertisers directly.

To enable these buyers to bid on digital inventory, the DSP has to plug into an SSP. This programmatic advertising supply chain is visualized in the graphic below.

因为网络共享，看视频或下载的时候会占用大量带宽，导致网络卡顿，影响他人的使用。速度太快还会被网管断开连接(下载Xcode或更新时经常出现)。下面是搜索到的两种限制网速的方式。苹果官方提供了限制系统整体网速的Network Link Conditioner 和 OpenBSD’s Packet Filter 命令行工具。