Tag: university

莫斯科大學的學生自己在宿舍架設宿舍網路的歷史故事 (2002～2013)

在 Lobster Daily 看到「Moscow state university network built by students」這篇，不過 Hacker News 上的討論多一點：「“Illegal” Moscow state university network built by students (2002-2013) (medium.com/pv.safronov)」。

莫斯科大學宿舍網路的故事，發生在 2002 年到 2013 年之間：

They had built a network on their own, which provided students Internet connection from 2002 till 2013 (when the administration effectively legalized this network).

算是老人懷舊的故事，不過看起來作者留下了大量的照片看起來就更有趣了...

查了一下資料，交大應該是 1993 年 1992 年就開始有宿舍網路了 (可能更早？)，而且是校方用同軸電纜 (Coaxial cable) 拉的，後來經過更新也換到雙絞線了 (UTP，Twisted pair)，現在應該是 1Gbps 的頻寬，不過不知道建築物之間是怎麼放的了。(大概還是光纖，依照集縮比應該是跑 10Gbps 的協定，S 系列的那幾個可能距離都太短，大概是 L 的吧，不知道是幾對...)

首先這是個橫跨整個主建築物的網路建制，分成五個大區塊：

從 Google Maps 拉一下距離，光是兩端的直線距離就快要 0.5km 了，應該沒找錯建築物，看起來是這棟沒錯...

從作者提供的圖片也可以看出來建築物本身超大：

回到網路的部份，本來是用 10Mbps 的 Hub 接 (算是 2002 年比較好取得的網路設備？)，但因為是 Hub 所以頻寬使用率不高 (Collision domain 的效率下降)，換成 Switch 後降低了很多不必要的流量：

In the beginning, there were only 10 Mbps hubs available. They were extremely slow because the packet arriving at one port was mirrored to all other ports, flooding the network with unnecessary traffic. Later they were replaced by L2 switches, that are smart enough to choose the destination port for the packet.

但宿舍網路是有競爭對手的，兩邊常常破壞對方 XDDD

Having two competing networks was a cherry on the top of it. They were cutting each other’s cables, executing DDoS attacks, stealing equipment, etc.

然後是拉光纖對接幾個主要的區塊，以上面剛剛拉出來的數字來看，應該是因為雙絞線 (UTP，Twisted pair) 的 100 公尺長度限制，所以這部份必須透過光纖：

To connect this router to the other parts of the network, we laid fiber cables through secret passages in the walls, ceilings, floors, and ventilation shafts.

然後用 Switch 再拉到每個房間 (所謂的 Last mile)：

然後外部就沒在怕你的拉：

還包括了把 UTP 的八芯線分開用的方法，這邊提到了 100Mbps 應該是升級上去了：

Most of the time, we managed to reduce the number of cables coming out of the window down to ~15. We could do this because of a simple trick: the regular ethernet cable (Cat 5e) has 8 wires. And to transmit 100 Mbps, you need just 4 of them. All 8 wires are required only for a 1 Gbps connection. So using a single cable, you can connect 2 clients who live close to each other. We always tried to do that if possible because the hole can’t fit so many cables.

往後拉一點的樣子：

後面講到很多故事以及常見的 trouble shooting 問題，現在的網路設備能支援的架構好太多，應該都有比較好的解法了...

Elsevier 限制加州大學的存取權限

三月的時候加州大學系統 (UC) 因為 Elsevier 不接受 open access 的條件而公開宣佈不續約 (參考「加州大學宣佈不與 Elsevier 續約」)，後來 Elsevier 應該是試著看看有沒有機會繼續合作，所以在這段期間還是一直提供服務給加州大學系統。

前幾天在 Hacker News 上看到「Elsevier cuts off UC’s access to its academic journals (latimes.com)」，總算是確定要動手了：「In act of brinkmanship, a big publisher cuts off UC’s access to its academic journals」。

不過也不是直接拔掉，而是限制存取權，看不到新東西 (以 2019/01/01 為界)：

As of Wednesday, Elsevier cut off access by UC faculty, staff and students to articles published since Jan. 1 in 2,500 Elsevier journals, including respected medical publications such as Cell and the Lancet and a host of engineering and scientific journals. Access to most material published in 2018 and earlier remains in force.

UC 提出的商業模式是讓投稿者負擔費用，而存取者不需要負擔，與現有的商業模式剛好相反。UC 提出的模式鼓勵「知識的散佈」，而現有的商業模式則是反過來，希望透過知識的散佈而賺～大～錢～發～大～財～：

UC demanded that the new contract reflect the principle of open access — that work produced on its campuses be available to all outside readers, for free.

That was a direct challenge to the business model of Elsevier and other big academic publishers. Traditionally, the publishers accept papers for publication for free but charge steep subscription fees. UC is determined to operate under an alternative model, in which researchers pay to have their papers published but not for subscriptions.

另外在 Hacker News 上的 comment 裡看到一些專案也正在進行，像是歐洲的「Plan S」也是在推動 open access：

The plan requires scientists and researchers who benefit from state-funded research organisations and institutions to publish their work in open repositories or in journals that are available to all by 2021.

另外「PubPub · Community Publishing」也是 open source 領域裡蠻有趣的計畫，後面看起來也有不少學術單位在支持。

加州大學宣佈不與 Elsevier 續約

加州大學 (這是一個大學系統，包括了十個校區，超過 25 萬的學生與 14 萬的教職員) 認為 Elsevier 沒有達到 open access 應有的標準，決定將不再跟 Elsevier 續約，並且發出新聞稿抨擊 Elsevier：「UC terminates subscriptions with world’s largest scientific publisher in push for open access to publicly funded research」。

As a leader in the global movement toward open access to publicly funded research, the University of California is taking a firm stand by deciding not to renew its subscriptions with Elsevier. Despite months of contract negotiations, Elsevier was unwilling to meet UC’s key goal: securing universal open access to UC research while containing the rapidly escalating costs associated with for-profit journals.

這應該是美國頂尖學院裡面的第一槍？後續會帶動多少單位不續訂...

Elsevier 讓德國的研究機構在還沒有續約的情況下繼續使用

德國的研究機構在 2017 年年底前，也就是與 Elsevier 的合約到期前，還是沒有續約，但 Elsevier 決定還是先繼續提供服務，暫時性的為期一年，繼續談判：

The Dutch publishing giant Elsevier has granted uninterrupted access to its paywalled journals for researchers at around 200 German universities and research institutes that had refused to renew their individual subscriptions at the end of 2017.

The institutions had formed a consortium to negotiate a nationwide licence with the publisher. They sought a collective deal that would give most scientists in Germany full online access to about 2,500 journals at about half the price that individual libraries have paid in the past. But talks broke down and, by the end of 2017, no deal had been agreed. Elsevier now says that it will allow the country’s scientists to access its paywalled journals without a contract until a national agreement is hammered out.

Elsevier 會這樣做主要是要避免讓德國的學術機構發現「沒有 Elsevier 其實也活的很好」。而不少研究人員已經知道這件事情，在大多數的情況下都有 Elsevier 的替代方案，不需要浪費錢簽那麼貴的費用：

Günter Ziegler, a mathematician at the Free University of Berlin and a member of the consortium's negotiating team, says that German researchers have the upper hand in the negotiations. “Most papers are now freely available somewhere on the Internet, or else you might choose to work with preprint versions,” he says. “Clearly our negotiating position is strong. It is not clear that we want or need a paid extension of the old contracts.”

替代方案有幾個方面，像是自由開放下載的 arXiv 愈來愈受到重視，很多研究者都會把投稿的論文在上面放一份 pre-print 版本 (甚至會更新)，而且近年來有些知名的證明只放在上面 (像是 Poincaré conjecture)。而且放在人家家裡比放在自己網站來的簡單 (不需要自己維護)，這都使得 arXiv 變成學術界新的標準平台。

除了 arXiv 外，其他領域也有自己習慣的平台。像是密碼學這邊的「Cryptology ePrint Archive」也運作很久了。

除了找平台外，放在自家網站上的論文 (通常是學校或是學術機構的個人空間)，也因為搜尋引擎的發達，使得大家更容易找到對應檔案可以下載。

而且更直接的攻擊性網站是 Sci-Hub，讓大家從 paywall 下載後丟上去公開讓人搜尋。雖然因為常常被封鎖的原因而常常在換網址，不過透過 Tor Browser (或是自己設定 Tor Proxy) 存取他們的 Hidden Service 就應該沒這個問題。

希望德國可以撐下去，證明其實已經不需要 Elsevier...

LinkedIn 依照他們的資料對美國的大專院校排名

在 Slashdot 上看到 LinkedIn 對美國的大專院校排名：「Be True To Your CS School: LinkedIn Ranks US Schools For Job-Seeking Programmers」。

軟體工程師的部份在這邊：「LinkedIn 大學排名 — 軟體開發人員」。Slashdot 上的 comment 瞬間就戰起來，然後還有人跑出來問怎麼沒有美國外的資料 XDDD

CMU 第一名不算奇怪，但 Stanford 意外的後面？