Newsletter No. 387

2 No. 387, 19.11.2011 「透 過雲計算技術服務使用電腦，就如用電一 般，只要接上插頭，按需要『用多少、付多 少』，不用理會背後的發電原理，又不用費心技術問題。」資 訊科技服務處雲計算部主管 蘇伯祥 這樣比喻近年興起的 雲計算服務模式。 隨着網絡傳輸日 趨快捷穩定，雲 計算技術愈來愈 普及，已成為全 球科技界關注的 新焦點，亦逐漸 滲入生活層面， 家居網絡服務 的廣告就常出現 「雲端儲存」這 一名詞。全球最 大網絡供應商之 一的思科系統公 司，於去年12月 的一項調查指 出，受訪的十三個國家逾二千名技術專業人員當中，百分之 五十二正使用或計劃使用雲計算服務，而在巴西、印度及中 國等正崛起國家，比率就更高。 與傳統電腦系統比較，新模式有何好處？蘇伯祥解釋：「前 者的程式或檔案往往儲存於單台式電腦的硬碟或伺服器 中，各部門需要自行添置軟硬件、購置儲存空間、並管理各 種程式，這就有如每部門各自購置及管理發電機，供電自 用。」當估計與實際用量有偏差，便會造成浪費；若各部門 自行開發相類似的程式，又會令資源重叠。 他續稱：「雲計算服務卻以嶄新的概念，將檔案、程式甚至 儲存空間等，存放於用者身處空間之外的『雲端』，即是以 互聯網為基礎的空間，讓用者按需要靈活的增減取用。」 用者無須增聘專人管理其軟硬件及程式；此外，可以取用 最新的科技，而價錢又比自購更低廉，也是雲計算服務優 勝之處。 中文大學資訊科技服務處於兩年前成立雲計算部，專門提 供雲計算服務予校內單位。服務分三個層面：軟體服務，如 電子文件管理系統、活動登記系統等；於2010年初開始提 供的平台服務，如網站建設及寄存，應用程式寄存等；於 一年前開始的基礎設施服務，包括虛擬機架設和伺服器支 援。部門可按需要與該處討論需要甚麼程度的支援。 蘇伯祥舉例說，部門若擬成立網頁，可自行建立，然後置 於資訊科技服務處的伺服器，又或採用該處的網頁應用程 式，而部門只需充當管理內容的角色，將內容及圖片上載， 毋須自行建立伺服器，更可減省技術管理工作，方便快捷。 不過，新技術的資訊保安問題，是業界普遍關注的課題。 不少政府機構或處理敏感資訊的部門，仍拒絕走上雲端， 認為非得由自己觸手可及的系統處理儲存不可。專研雲計 算技術的計算機科學與工程學系助理教授 李柏晴 博士表 示，雲計算模式是將數據儲存在不同的『雲端』，一些重 要資料若儲於公司以外的地方，定要確保安全，這是一大 挑戰。 他現時的其中一項研究，便是嘗試從理論層面建立一個系 統，讓用者在刪除儲於雲上的數據時，可以完全刪除散落 於不同雲端的複本。除了研究，他亦即將任教雲計算概論 這於2011學年下學期新增設的科目，讓學生掌握這種新模 式的特點。「這科目供主修計算機科學與工程學的高年級 學生選修，屆時學系會設有雲端平台，讓學生實習。」 ‘C loud computing is a model that delivers IT infrastructure as simply as electricity from the socket. You don’t have to bother with the principle of electricity generation or the maintenance process. You pay only for what you use,’ Mr. So Pak-cheung Roger , head of the Cloud Computing Division of Information Technology Services Office (ITSC), drew an analogy between electricity and cloud computing. Cloud computing is the buzzword of the moment in the technology field as internet connectivity becomes increasingly speedy and stable. Terms like ‘cloud storage’ are common in advertisements of household network services, showing that the new technology has already penetrated daily life. A study by Cisco System Incorporation, a world-leading networking supplier, which involved a survey of more than 2,000 IT professionals in 13 countries, found that 52 per cent are using—or plan to use—cloud computing services in the near future. The percentages are even higher in the emerging markets of Brazil, India, and China. Talking about the advantage of cloud computing over traditional computing, Roger said, ‘In the traditional computing system, all computer applications and data files are stored in the hard disk of individual computers or servers. When new software, hardware, and extra space are needed, an office has to acquire and install them as well as to administer the applications. This is somewhat like having each office buy and manage an electric generator on its own’. If the difference between the estimated and actual usage is huge, there will be wastage. If different offices develop similar programs simultaneously, there’s an overlap of effort. He continued, ‘Cloud computing is a brand new concept in the computing operation model. It proposes to keep all data files, applications and storage somewhere outside the computer in the internet space named “cloud”. Users can use them on-demand and with much flexibility.’ According to the new model, offices will no longer need to invest in technical maintenance staff and can share new IT services at lower prices. The Cloud Computing Division of the ITSC was established two years ago, providing solutions to assist departments in automating and enhancing their administrative and office work. Three levels of services are offered: Cloud Software Service (SaaS) such as the Electronic Document Management System and the Online Event Registration System; the Cloud Platform Service (PaaS), available from early 2010, including the building and hosting of websites and applications; the Cloud Infrastructure Service (IaaS), begun a year ago, including virtual machine server hosting and server management support. University offices can contact the ITSC directly to discuss the support they need. 飛上雲端的科技 A Walk in the Clouds 蘇伯祥先生 Mr. So Pak-cheung Roger