mirror of
https://github.com/LCTT/TranslateProject.git
synced 2025-02-03 23:40:14 +08:00
Merge remote-tracking branch 'LCTT/master'
This commit is contained in:
wxy
commit
c1ada63f84
@ -3,10 +3,9 @@
|
||||
|
||||
[][8]
|
||||
|
||||
|
||||
HackerRank 最近公布了 2018 年开发者技能报告的结果，其中向程序员询问了他们何时开始编码。
|
||||
|
||||
39,441 名专业和学生开发者于 2016 年 10 月 16 日至 11 月 1 日完成了在线调查，超过 25％ 的被调查的开发者在 16 岁前编写了他们的第一段代码。
|
||||
39,441 名专业人员和学生开发者于 2016 年 10 月 16 日至 11 月 1 日完成了在线调查，超过 25％ 的被调查的开发者在 16 岁前编写了他们的第一段代码。（LCTT 译注：日期恐有误）
|
||||
|
||||
### 程序员是如何学习的
|
||||
|
||||
@ -16,7 +15,7 @@ HackerRank 最近公布了 2018 年开发者技能报告的结果，其中向程
|
||||
|
||||
开发者平均了解四种语言，但他们想学习更多语言。
|
||||
|
||||
对学习的渴望因人而异 - 18 至 24 岁的开发者计划学习 6 种语言，而 35 岁以上的开发者只计划学习 3 种语言。
|
||||
对学习的渴望因人而异 —— 18 至 24 岁的开发者计划学习 6 种语言，而 35 岁以上的开发者只计划学习 3 种语言。
|
||||
|
||||
[][5]
|
||||
|
||||
@ -46,9 +45,9 @@ HackerRank 说：“在某些方面，我们发现了一个小矛盾。开发人
|
||||
|
||||
via: https://mybroadband.co.za/news/smartphones/246583-how-programmers-learn-to-code.html
|
||||
|
||||
作者：[Staff Writer ][a]
|
||||
作者：[Staff Writer][a]
|
||||
译者：[geekpi](https://github.com/geekpi)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
校对：[wxy](https://github.com/wxy)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
42
sources/talk/20180221 3 warning flags of DevOps metrics.md
Normal file
42
sources/talk/20180221 3 warning flags of DevOps metrics.md
Normal file
@ -0,0 +1,42 @@
|
||||
3 warning flags of DevOps metrics
|
||||
======
|
||||
|
||||
|
||||
Metrics. Measurements. Data. Monitoring. Alerting. These are all big topics for DevOps and for cloud-native infrastructure and application development more broadly. In fact, acm Queue, a magazine published by the Association of Computing Machinery, recently devoted an [entire issue][1] to the topic.
|
||||
|
||||
I've argued before that we conflate a lot of things under the "metrics" term, from key performance indicators to critical failure alerts to data that may be vaguely useful someday for something or other. But that's a topic for another day. What I want to discuss here is how metrics affect behavior.
|
||||
|
||||
In 2008, Daniel Ariely published [Predictably Irrational][2] , one of a number of books written around that time that introduced behavioral psychology and behavioral economics to the general public. One memorable quote from that book is the following: "Human beings adjust behavior based on the metrics they're held against. Anything you measure will impel a person to optimize his score on that metric. What you measure is what you'll get. Period."
|
||||
|
||||
This shouldn't be surprising. It's a finding that's been repeatedly confirmed by research. It should also be familiar to just about anyone with business experience. It's certainly not news to anyone in sales management, for example. Base sales reps' (or their managers'!) bonuses solely on revenue, and they'll discount whatever it takes to maximize revenue even if it puts margin in the toilet. Conversely, want the sales force to push a new product line—which will probably take extra effort—but skip the [spiffs][3]? Probably not happening.
|
||||
|
||||
And lest you think I'm unfairly picking on sales, this behavior is pervasive, all the way up to the CEO, as Ariely describes in [a 2010 Harvard Business Review article][4]. "CEOs care about stock value because that's how we measure them. If we want to change what they care about, we should change what we measure," writes Ariely.
|
||||
|
||||
Think developers and operations folks are immune from such behaviors? Think again. Let's consider some problematic measurements. They're not all bad or wrong but, if you rely too much on them, warning flags should go up.
|
||||
|
||||
### Three warning signs for DevOps metrics
|
||||
|
||||
First, there are the quantity metrics. Lines of code or bugs fixed are perhaps self-evidently absurd. But there are also the deployments per week or per month that are so widely quoted to illustrate DevOps velocity relative to more traditional development and deployment practices. Speed is good. It's one of the reasons you're probably doing DevOps—but don't reward people on it excessively relative to quality and other measures.
|
||||
|
||||
Second, it's obvious that you want to reward individuals who do their work quickly and well. Yes. But. Whether it's your local pro sports team or some project team you've been on, you can probably name someone who was really a talent, but was just so toxic and such a distraction for everyone else that they were a net negative for the team. Moral: Don't provide incentives that solely encourage individual behaviors. You may also want to put in place programs, such as peer rewards, that explicitly value collaboration. [As Red Hat's Jen Krieger told me][5] in a podcast last year: "Having those automated pots of awards, or some sort of system that's tracked for that, can only help teams feel a little more cooperative with one another as in, 'Hey, we're all working together to get something done.'"
|
||||
|
||||
The third red flag area is incentives that don't actually incent because neither the individual nor the team has a meaningful ability to influence the outcome. It's often a good thing when DevOps metrics connect to business goals and outcomes. For example, customer ticket volume relates to perceived shortcomings in applications and infrastructure. And it's also a reasonable proxy for overall customer satisfaction, which certainly should be of interest to the executive suite. The best reward systems to drive DevOps behaviors should be tied to specific individual and team actions as opposed to just company success generally.
|
||||
|
||||
You've probably noticed a common theme. That theme is balance. Velocity is good but so is quality. Individual achievement is good but not when it damages the effectiveness of the team. The overall success of the business is certainly important, but the best reward systems also tie back to actions and behaviors within development and operations.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/article/18/2/three-warning-flags-devops-metrics
|
||||
|
||||
作者：[Gordon Haff][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:https://opensource.com/users/ghaff
|
||||
[1]:https://queue.acm.org/issuedetail.cfm?issue=3178368
|
||||
[2]:https://en.wikipedia.org/wiki/Predictably_Irrational
|
||||
[3]:https://en.wikipedia.org/wiki/Spiff
|
||||
[4]:https://hbr.org/2010/06/column-you-are-what-you-measure
|
||||
[5]:http://bitmason.blogspot.com/2015/09/podcast-making-devops-succeed-with-red.html
|
||||
@ -1,3 +1,5 @@
|
||||
Translating by MjSeven
|
||||
|
||||
My Adventure Migrating Back To Windows
|
||||
======
|
||||
I have had linux as my primary OS for about a decade now, and primarily use Ubuntu. But with the latest release I have decided to migrate back to an OS I generally dislike, Windows 10.
|
||||
|
||||
@ -0,0 +1,119 @@
|
||||
Learn to code with Thonny — a Python IDE for beginners
|
||||
======
|
||||
|
||||
|
||||
Learning to program is hard. Even when you finally get your colons and parentheses right, there is still a big chance that the program doesn’t do what you intended. Commonly, this means you overlooked something or misunderstood a language construct, and you need to locate the place in the code where your expectations and reality diverge.
|
||||
|
||||
Programmers usually tackle this situation with a tool called a debugger, which allows running their program step-by-step. Unfortunately, most debuggers are optimized for professional usage and assume the user already knows the semantics of language constructs (e.g. function call) very well.
|
||||
|
||||
Thonny is a beginner-friendly Python IDE, developed in [University of Tartu][1], Estonia, which takes a different approach as its debugger is designed specifically for learning and teaching programming.
|
||||
|
||||
Although Thonny is suitable for even total beginners, this post is meant for readers who have at least some experience with Python or another imperative language.
|
||||
|
||||
### Getting started
|
||||
|
||||
Thonny is included in Fedora repositories since version 27. Install it with sudo dnf install thonny or with a graphical tool of your choice (such as Software).
|
||||
|
||||
When first launching Thonny, it does some preparations and then presents an empty editor and the Python shell. Copy following program text into the editor and save it into a file (Ctrl+S).
|
||||
```
|
||||
n = 1
|
||||
while n < 5:
|
||||
print(n * "*")
|
||||
n = n + 1
|
||||
|
||||
```
|
||||
|
||||
Let’s first run the program in one go. For this press F5 on the keyboard. You should see a triangle made of periods appear in the shell pane.
|
||||
|
||||
![A simple program in Thonny][2]
|
||||
|
||||
Did Python just analyze your code and understand that you wanted to print a triangle? Let’s find out!
|
||||
|
||||
Start by selecting “Variables” from the “View” menu. This opens a table which will show us how Python manages program’s variables. Now run the program in debug mode by pressing Ctrl+F5 (or Ctrl+Shift+F5 in XFCE). In this mode Thonny makes Python pause before each step it takes. You should see the first line of the program getting surrounded with a box. We’ll call this the focus and it indicates the part of the code Python is going to execute next.
|
||||
|
||||
![Thonny debugger focus][3]
|
||||
|
||||
The piece of code you see in the focus box is called assignment statement. For this kind of statement, Python is supposed to evaluate the expression on the right and store the value under the name shown on the left. Press F7 to take the next step. You will see that Python focused on the right part of the statement. In this case the expression is really simple, but for generality Thonny presents the expression evaluation box, which allows turning expressions into values. Press F7 again to turn the literal 1 into value 1. Now Python is ready to do the actual assignment — press F7 again and you should see the variable n with value 1 appear in the variables table.
|
||||
|
||||
![Thonny with variables table][4]
|
||||
|
||||
Continue pressing F7 and observe how Python moves forward with really small steps. Does it look like something which understands the purpose of your code or more like a dumb machine following simple rules?
|
||||
|
||||
### Function calls
|
||||
|
||||
Function call is a programming concept which often causes great deal of confusion to beginners. On the surface there is nothing complicated — you give name to a code and refer to it (call it) somewhere else in the code. Traditional debuggers show us that when you step into the call, the focus jumps into the function definition (and later magically back to the original location). Is it the whole story? Do we need to care?
|
||||
|
||||
Turns out the “jump model” is sufficient only with the simplest functions. Understanding parameter passing, local variables, returning and recursion all benefit from the notion of stack frame. Luckily, Thonny can explain this concept intuitively without sweeping important details under the carpet.
|
||||
|
||||
Copy following recursive program into Thonny and run it in debug mode (Ctrl+F5 or Ctrl+Shift+F5).
|
||||
```
|
||||
def factorial(n):
|
||||
if n == 0:
|
||||
return 1
|
||||
else:
|
||||
return factorial(n-1) * n
|
||||
|
||||
print(factorial(4))
|
||||
|
||||
```
|
||||
|
||||
Press F7 repeatedly until you see the expression factorial(4) in the focus box. When you take the next step, you see that Thonny opens a new window containing function code, another variables table and another focus box (move the window to see that the old focus box is still there).
|
||||
|
||||
![Thonny stepping through a recursive function][5]
|
||||
|
||||
This window represents a stack frame, the working area for resolving a function call. Several such windows on top of each other is called the call stack. Notice the relationship between argument 4 on the call site and entry n in the local variables table. Continue stepping with F7 and observe how new windows get created on each call and destroyed when the function code completes and how the call site gets replaced by the return value.
|
||||
|
||||
### Values vs. references
|
||||
|
||||
Now let’s make an experiment inside the Python shell. Start by typing in the statements shown in the screenshot below:
|
||||
|
||||
![Thonny shell showing list mutation][6]
|
||||
|
||||
As you see, we appended to list b, but list a also got updated. You may know why this happened, but what’s the best way to explain it to a beginner?
|
||||
|
||||
When teaching lists to my students I tell them that I have been lying about Python memory model. It is actually not as simple as the variables table suggests. I tell them to restart the interpreter (the red button on the toolbar), select “Heap” from the “View” menu and make the same experiment again. If you do this, then you see that variables table doesn’t contain the values anymore — they actually live in another table called “Heap”. The role of the variables table is actually to map the variable names to addresses (or ID-s) which refer to the rows in the heap table. As assignment changes only the variables table, the statement b = a only copied the reference to the list, not the list itself. This explained why we see the change via both variables.
|
||||
|
||||
![Thonny in heap mode][7]
|
||||
|
||||
(Why do I postpone telling the truth about the memory model until the topic of lists? Does Python store lists differently compared to floats or strings? Go ahead and use Thonny’s heap mode to find this out! Tell me in the comments what do you think!)
|
||||
|
||||
If you want to understand the references system deeper, copy following program to Thonny and small-step (F7) through it with the heap table open.
|
||||
```
|
||||
def do_something(lst, x):
|
||||
lst.append(x)
|
||||
|
||||
a = [1,2,3]
|
||||
n = 4
|
||||
do_something(a, n)
|
||||
print(a)
|
||||
|
||||
```
|
||||
|
||||
Even if the “heap mode” shows us authentic picture, it is rather inconvenient to use. For this reason, I recommend you now switch back to normal mode (unselect “Heap” in the View menu) but remember that the real model includes variables, references and values.
|
||||
|
||||
### Conclusion
|
||||
|
||||
The features I touched in this post were the main reason for creating Thonny. It’s easy to form misconceptions about both function calls and references but traditional debuggers don’t really help in reducing the confusion.
|
||||
|
||||
Besides these distinguishing features, Thonny offers several other beginner friendly tools. Please look around at [Thonny’s homepage][8] to learn more!
|
||||
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://fedoramagazine.org/learn-code-thonny-python-ide-beginners/
|
||||
|
||||
作者：[Aivar Annamaa][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:https://fedoramagazine.org/
|
||||
[1]:https://www.ut.ee/en
|
||||
[2]:https://fedoramagazine.org/wp-content/uploads/2017/12/scr1.png
|
||||
[3]:https://fedoramagazine.org/wp-content/uploads/2017/12/thonny-scr2.png
|
||||
[4]:https://fedoramagazine.org/wp-content/uploads/2017/12/thonny-scr3.png
|
||||
[5]:https://fedoramagazine.org/wp-content/uploads/2017/12/thonny-scr4.png
|
||||
[6]:https://fedoramagazine.org/wp-content/uploads/2017/12/thonny-scr5.png
|
||||
[7]:https://fedoramagazine.org/wp-content/uploads/2017/12/thonny-scr6.png
|
||||
[8]:http://thonny.org
|
||||
103
sources/tech/20180222 Linux LAN Routing for Beginners- Part 1.md
Normal file
103
sources/tech/20180222 Linux LAN Routing for Beginners- Part 1.md
Normal file
@ -0,0 +1,103 @@
|
||||
Linux LAN Routing for Beginners: Part 1
|
||||
======
|
||||
|
||||
|
||||
Once upon a time we learned about [IPv6 routing][1]. Now we're going to dig into the basics of IPv4 routing with Linux. We'll start with an overview of hardware and operating systems, and IPv4 addressing basics, and next week we'll setup and test routing.
|
||||
|
||||
### LAN Router Hardware
|
||||
|
||||
Linux is a real networking operating system, and always has been, with network functionality built-in from the beginning. Building a LAN router is simple compared to building a gateway router that connects your LAN to the Internet. You don't have to hassle with security or firewall rules, which are still complicated by having to deal with NAT, network address translation, an affliction of IPv4. Why do we not drop IPv4 and migrate to IPv6? The life of the network administrator would be ever so much simpler.
|
||||
|
||||
But I digress. Ideally, your Linux router is a small machine with at least two network interfaces. Linux Gizmos has a great roundup of single-board computers here: [Catalog of 98 open-spec, hacker friendly SBCs][2]. You could use an old laptop or desktop PC. You could use a compact computer, like the ZaReason Zini or the System76 Meerkat, though these are a little pricey at nearly $600. But they are stout and reliable, and you're not wasting money on a Windows license.
|
||||
|
||||
The Raspberry Pi 3 Model B is great for lower-demand routing. It has a single 10/100 Ethernet port, onboard 2.4GHz 802.11n wireless, and four USB ports, so you can plug in more USB network interfaces. USB 2.0 and the slower onboard network interfaces make the Pi a bit of a network bottleneck, but you can't beat the price ($35 without storage or power supply). It supports a couple dozen Linux flavors, so chances are you can have your favorite. The Debian-based Raspbian is my personal favorite.
|
||||
|
||||
### Operating System
|
||||
|
||||
You might as well stuff the smallest version of your favorite Linux on your chosen hardware thingy, because the specialized router operating systems such as OpenWRT, Tomato, DD-WRT, Smoothwall, Pfsense, and so on all have their own non-standard interfaces. In my admirable opinion this is an unnecessary complication that gets in the way rather than helping. Use the standard Linux tools and learn them once.
|
||||
|
||||
The Debian net install image is about 300MB and supports multiple architectures, including ARM, i386, amd64, and armhf. Ubuntu's server net installation image is under 50MB, giving you even more control over what packages you install. Fedora, Mageia, and openSUSE all offer compact net install images. If you need inspiration browse [Distrowatch][3].
|
||||
|
||||
### What Routers Do
|
||||
|
||||
Why do we even need network routers? A router connects different networks. Without routing every network space is isolated, all sad and alone with no one to talk to but the same boring old nodes. Suppose you have a 192.168.1.0/24 and a 192.168.2.0/24 network. Your two networks cannot talk to each other without a router connecting them. These are Class C private networks with 254 usable addresses each. Use ipcalc to get nice visual information about them:
|
||||
```
|
||||
$ ipcalc 192.168.1.0/24
|
||||
Address: 192.168.1.0 11000000.10101000.00000001. 00000000
|
||||
Netmask: 255.255.255.0 = 24 11111111.11111111.11111111. 00000000
|
||||
Wildcard: 0.0.0.255 00000000.00000000.00000000. 11111111
|
||||
=>
|
||||
Network: 192.168.1.0/24 11000000.10101000.00000001. 00000000
|
||||
HostMin: 192.168.1.1 11000000.10101000.00000001. 00000001
|
||||
HostMax: 192.168.1.254 11000000.10101000.00000001. 11111110
|
||||
Broadcast: 192.168.1.255 11000000.10101000.00000001. 11111111
|
||||
Hosts/Net: 254 Class C, Private Internet
|
||||
|
||||
```
|
||||
|
||||
I like that ipcalc's binary output makes a visual representation of how the netmask works. The first three octets are the network address, and the fourth octet is the host address, so when you are assigning host addresses you "mask" out the network portion and use the leftover. Your two networks have different network addresses, and that is why they cannot communicate without a router in between them.
|
||||
|
||||
Each octet is 256 bytes, but that does not give you 256 host addresses because the first and last values, 0 and 255, are reserved. 0 is the network identifier, and 255 is the broadcast address, so that leaves 254 host addresses. ipcalc helpfully spells all of this out.
|
||||
|
||||
This does not mean that you never have a host address that ends in 0 or 255. Suppose you have a 16-bit prefix:
|
||||
```
|
||||
$ ipcalc 192.168.0.0/16
|
||||
Address: 192.168.0.0 11000000.10101000. 00000000.00000000
|
||||
Netmask: 255.255.0.0 = 16 11111111.11111111. 00000000.00000000
|
||||
Wildcard: 0.0.255.255 00000000.00000000. 11111111.11111111
|
||||
=>
|
||||
Network: 192.168.0.0/16 11000000.10101000. 00000000.00000000
|
||||
HostMin: 192.168.0.1 11000000.10101000. 00000000.00000001
|
||||
HostMax: 192.168.255.254 11000000.10101000. 11111111.11111110
|
||||
Broadcast: 192.168.255.255 11000000.10101000. 11111111.11111111
|
||||
Hosts/Net: 65534 Class C, Private Internet
|
||||
|
||||
```
|
||||
|
||||
ipcalc lists your first and last host addresses, 192.168.0.1 and 192.168.255.254. You may have host addresses that end in 0 and 255, for example 192.168.1.0 and 192.168.0.255, because those fall in between the HostMin and HostMax.
|
||||
|
||||
The same principles apply regardless of your address blocks, whether they are private or public, and don't be shy about using ipcalc to help you understand.
|
||||
|
||||
### CIDR
|
||||
|
||||
CIDR (Classless Inter-Domain Routing) was created to extend IPv4 by providing variable-length subnet masking. CIDR allows finer slicing-and-dicing of your network space. Let ipcalc demonstrate:
|
||||
```
|
||||
$ ipcalc 192.168.1.0/22
|
||||
Address: 192.168.1.0 11000000.10101000.000000 01.00000000
|
||||
Netmask: 255.255.252.0 = 22 11111111.11111111.111111 00.00000000
|
||||
Wildcard: 0.0.3.255 00000000.00000000.000000 11.11111111
|
||||
=>
|
||||
Network: 192.168.0.0/22 11000000.10101000.000000 00.00000000
|
||||
HostMin: 192.168.0.1 11000000.10101000.000000 00.00000001
|
||||
HostMax: 192.168.3.254 11000000.10101000.000000 11.11111110
|
||||
Broadcast: 192.168.3.255 11000000.10101000.000000 11.11111111
|
||||
Hosts/Net: 1022 Class C, Private Internet
|
||||
|
||||
```
|
||||
|
||||
The netmask is not limited to whole octets, but rather crosses the boundary between the third and fourth octets, and the subnet portion ranges from 0 to 3, and not from 0 to 255. The number of available hosts is not a multiple of 8 as it is when the netmask is defined by whole octets.
|
||||
|
||||
Your homework is to review CIDR and how the IPv4 address space is allocated between public, private, and reserved blocks, as this is essential to understanding routing. Setting up routes is not complicated as long as you have a good knowledge of addressing.
|
||||
|
||||
Start with [Understanding IP Addressing and CIDR Charts][4], [IPv4 Private Address Space and Filtering][5], and [IANA IPv4 Address Space Registry][6]. Then come back next week to learn how to create and manage routes.
|
||||
|
||||
Learn more about Linux through the free ["Introduction to Linux" ][7]course from The Linux Foundation and edX.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://www.linux.com/learn/intro-to-linux/2018/2/linux-lan-routing-beginners-part-1
|
||||
|
||||
作者：[Carla Schroder][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:https://www.linux.com/users/cschroder
|
||||
[1]:https://www.linux.com/learn/intro-to-linux/2017/7/practical-networking-linux-admins-ipv6-routing
|
||||
[2]:http://linuxgizmos.com/catalog-of-98-open-spec-hacker-friendly-sbcs/#catalog
|
||||
[3]:http://distrowatch.org/
|
||||
[4]:https://www.ripe.net/about-us/press-centre/understanding-ip-addressing
|
||||
[5]:https://www.arin.net/knowledge/address_filters.html
|
||||
[6]:https://www.iana.org/assignments/ipv4-address-space/ipv4-address-space.xhtml
|
||||
[7]:https://training.linuxfoundation.org/linux-courses/system-administration-training/introduction-to-linux
|
||||
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Block a user