莊子、外篇『胠篋第十』上有一段文字︰
故跖之徒問於跖曰：「盜亦有道乎？」跖曰：「何適而無有道邪？ 妄意室中之藏，聖也；入先，勇也；出後，義也；知可否，知也；分均，仁也。五者不備而能成大盜者，天下未之有也。」由是觀之 ，善人不得聖人之道不立，跖不得聖人之道不行；天下之善人少而不善人多，則聖人之利天下也少而害天下也多。
並有雜篇、盜跖第二十九一段故事，讀來令人津津有味，難道義賊廖添丁乃盜跖之傳人乎？東方的『大盜』哲學和西方的『駭客』觀點能否作比較呢？如果要比較，當然得知道 hacker 的源流 。有位 Ben Yagoda 先生寫了一篇『 Hack 簡史』寫的很好。在此簡略的介紹，文中首先引用作者與美國方言學會會長談 “hack” 和 “hacker” 時的對話，會長說︰
the earliest examples share a relatively benign sense of “working on” a tech problem in a different, presumably more creative way than what’s outlined in an instruction manual.
也就是說最早所謂駭客是「創造性的使用說明書，用不一樣的辦法解決工程問題的人」。其後作者寫到，“hack” 一字 1955年就在 M.I.T 出現了，到了 1975 年 M.I.T 的電腦行話語詞表開啟了將 hacker 用於對電腦狂熱份子的宣言，並於所謂『八條定義』中開宗明義的說「駭客原指用大刀闊斧作傢俱的人」；其中第八條寫到︰
[deprecated] A malicious meddler who tries to discover sensitive information by poking around. Hence password hacker, network hacker. The correct term for this sense is cracker.
此條中〔勿用〕deprecated 一詞所說的『懷著惡意愛管閑事』者成了今天的黑帽駭客，或乾脆說黑客；相反的『本著活潑創造精神』者則變成今天的白帽駭客，也許簡稱為素客。同時作者論及駭客一詞的詞意變化、應用領域擴大…等等，於此就不多贅敘了。
十年後，1985 年法國心理學家愛德華·德·波諾著作『六頂思考帽』 ，在此引用中文維基百科上的兩頂帽：
黑色思考帽：代表缺點，隱患，問題，風險；當戴上黑色思考帽， 代表專注於考慮事情的負面，思考短,中,長期的風險，潛在與明顯的危機，是一頂行動前必須帶上的帽子。
白色思考帽：提供事實與數據，還包含考慮事情的各個面向，必須深入地挖掘事實，也必須將他人的意見考慮進來。
想想也許光明與黑暗，正是人同此心、心同此理的。希望能用正面思維來看待駭客一詞，就如同這本書名所想說的︰
Raspberry Pi Hacks
Tips & Tools for Making Things with the Inexpensive Linux Computer
By Ruth Suehle, Tom Callaway
那難道『大盜』與『駭客』真的能比較嗎？前面談了駭客的觀點，現在說說大盜的哲學。老子的哲學反對人為的矯飾，強調人為的禮儀並非自然而然。所以他講『大白若辱 』、『大音希聲』、『大象无形』、…等等，是非常重要的『逆向思維』觀念，能打破僵固的教條主義，莊子發揚老子的哲學，以其獨特的『創造性寓言』撼動著讀者的心靈，所以寫『逍遙遊』、『齊物論』、…以及論說「至大无外、至小无內」種種。因此從『創造性』方面來看，東西方或可相通，由『義』的角度來講，東西方亦或不相同。
─── 《盜亦有道？》
如果一個人能用
六頂思考帽
這方法強調從不同角度思考同一個問題，客觀地分析各種意見，最後作出結論。六帽子：紅、黃、黑、綠、白和藍。
- 白色思考帽：提供事實與數據，還包含考慮事情的各個面，必須深入地挖掘事實，也必須將他人的意見考慮進來
- 紅色思考帽：代表情緒，直覺，感覺；當戴上紅色思考帽，代表允許表達自己的喜好與感覺，運用在投票與決策
- 黃色思考帽：代表好處，利益，價值；當戴上黃色思考帽，代表專注於考慮事情的正面，思考短、中、長期的好處、價值與利益 ，也包含了挖掘潛藏的優點
- 黑色思考帽：代表缺點，隱患，問題，風險；當戴上黑色思考帽 ，代表專注於考慮事情的負面，思考短,中,長期的風險，潛在與明顯的危機，是一頂行動前必須帶上的帽子
- 綠色思考帽：代表創新與創意，是一頂創意帽，水平思考就是綠帽的延伸
- 藍色思考帽：是一頂控制思維的帽子，也稱為帽子的帽子，是一頂主持帽,系統地使用帽子時，必須以藍帽為開始，藍帽為結束
來思考，將通『逆向思維』乎？
那麼假設『問題答案』︰
RPi 3B+ gigabit ethernet bad download speeds.
sudo apt-get install speedtest-cli
I have tested the new RPi 3B+ over a fresh install latest raspbian and official PSU raspberry pi and good SD card A1 class.
The performance on download speeds from internet is about 40 Mbit/s but my ISP is 200 Mbit/s and on my old Rpi3B I obtain 80 Mbit/s download speed.
I believe is a problem with kernel driver.I hope is not a related hardware problem.
In this web page someone discover similar problem…
https://volumio.org/raspberry-pi-3-b-pl … o-review/
“So, it seems that there is still some issue (hopefully it’s driver related) to the Ethernet controller, which seems to give up lots of packets in high-bandwidth situations. I am however pretty confident that the foundation will solve this issue, as it’s not uncommon that hardware performances get dramatic improvements as software gets tuned up after community feedbacks.”
Thanks in advance.
…
為已知︰
Re: RPi 3B+ gigabit ethernet bad download speeds.
Eichhorn18 wrote: ↑
Wed Aug 29, 2018 9:06 amIs there any known issues with cifs as an alternative to samba?
Just for another data point, I have 800 Mbit/s service and i’ve connected a laptop with gigabit ethernet and gotten that delivery speed. The Raspberry Pi 3B+ on the same physical wire gives between 120 – 165 Mbit/s download, and upload between 100 – 220 Mbit/s.
CIFS is a dialect of the SMB protocol that Samba implements.
We’re fairly certain that has been resolved now anyway. It was stalling a single TCP connection rather than a speed issue.
https://github.com/raspberrypi/linux/issues/2449
https://github.com/raspberrypi/linux/issues/2482
Yours sounds like the standard type of flow control issue. You have a bottle-neck in the USB2 interface from the ethernet adapter to the Pi of a theoretical max of 480Mbit/s, but more realisitcally around 250Mbit/s. The adapter will be sending ethernet flow control pause frames when it backs up, but those only work over the local network. There is no mechanism to make an internet server back off other than rely on TCP’s standard backoff/retry mechanisms.
Re: RPi 3B+ gigabit ethernet bad download speeds.
Eichhorn18 wrote: ↑
Fri Aug 31, 2018 11:46 amCopied from the SD card. I realize that in itself is an unfortunate bottleneck.
I have also written files that are stored in RAM, directly to a network mounted folder on a windows machine using CIFS. The transfer speed from RAM to the network folder (over a gigabit network and onto a gigabit enabled machine) was 30 MB/s, transferring 184MB of files in 6.13 sec.
Well, from RAM you get 30 Mbyte/s. That is 240 Mbit/s which is approaching the expected max rate of ethernet on a RPi 3B+.
Re: RPi 3B+ gigabit ethernet bad download speeds.
It’s true that is pretty decent. I wonder why the big difference (approximately 50%) for an internet connection that is supposed to give 800 Mbits/s on gigabit ethernet computers. What is the raspberry Pi doing for a speed test that it’s not doing for a local network transfer–assuming the internet connection is not the limiting factor.
可否『還原過程』也！