tirsdag 05 oktober 2004, 04:05, skrev Vagrant Cascadian: > that's why i was wondering if you were exploring lessdisks as a > "half-thick client", because the memory and CPU requirements seemed > high for a typical lessdisks "thin-client".
I think I'll give a more strategic background for why we ask, and what the expectation are from the municipal department of education in Oslo. We already have thin clients with LTSP in Skolelinux. A lot of schools uses the preloaded architecture with huge success in Norway, Europa and Africa[1] - even in Hawaii[2]. The architecture[3] in Skolelinux is made for low bandwidth. It allows use of Internet on a telephone modem (28.8 kbps), and the maintenance could be done by a ssh-tunnel. You can use the network with no Internet at all. The architecture is fully expandable. Different IP-services can be placed on it's own machine, or in a central centre of operation with small changes in the DNS. This is already in production in The Norwegian research network[4] that is in a migration process to Debian, inspired by the Skolelinux effort. [1] http://www.fair.no/english/about_fair.htm [2] http://www.desktoplinux.com/news/NS6201542989.html [3] http://developer.skolelinux.no/arkitektur/arkitektur.html.en [4] http://www.uninett.no/index.en.html The municipal department of education in Oslo expect us to place the application servers centrally for 175 schools. The idea is that all the servers should be placed in one building, and they should rely on heavily use of thin clients on a serverfram. At our first meeting they told us that they had solved this with Windows and Citrix. In real life it's like this: 1. The Windows thin clients have heavy restrictions, where media rich applications is not an option, which is application that is based on Flash, Java and streaming. 2. They have placed 1-2 servers at the schools give access to reasonable login with Active Directory, replication of files to "multimedia-ready" workstation, and some Internet services. 3. The bandwidth limitation to the schools are between 2-8 Mbps. The schools have 90-150 workplaces where 80-90% are thin clients, and the schools have 10-20% workstations to tackle media rich applications (Video editing, Flash, Java etc.). It works, but it's not especially impressive. Anyway. 1. In our believe we need a server at the school in some form or another anyway. We are technicians, and know that the network gives some limitation. We really want to give the pupils media rich application if all the servers are placed in a centralised serverfarm - because the national exam's in English is mandatory, made with a Flash application: http://www.intermedia.uib.no/projects/bite-it Today many schools has tested the national exam with Skolelinux, and it work as expected with todays architecture. 2. The pupils and teachers don't know the difference between thin clients and a workstation anyway. Then we need to give them Flash and Java (goods forbid). Through testing we know that some of the Flash-applications eats bandwidth in the LTSP-setup. The standard use i 2 Mpbs for every client. With some applications it is 10 Mbps. We really wants to reduce that in our standard setup. This has to follow our black box idea where everything is done automaticly, as our architecture and installations shows. 3. Even if we have already solved the problem with media rich applications with our black box approach, and it's in use in whole of Norway, The municipal department of education in Oslo wants a server farm - period. An even if they don't really have that today, our mission is to support that idea. And some of the people we talk to, almost all, did not listen to our argument that it's no problem to maintain and operate a large "black box" solution for all the schools, making Flash-based English exams working much better than today etc.It's also an argument about cooling and housing (a room) for a local server at the schools. 4. The people on the other side of the table lacks some insight about networking in large where you make a IP arcitecture that takes care for the bottleneck. When we make this report it will be well documentet what the possibilities are. By the way -- it's the politicians that want this done. They have cut the budget from 60 million to 20 a year, with a clear message. Give Linux a try - you don't get more money. 5. So now we explore FreeNX to copy the Citrix-solution 100%. We also need to place some applications on the thin client, just to speed up Flash, and reduce the bandwidth requirement when using FreeNX, because running FreeNX with Flash gives bandwidth requirement with 500kbps in peak, even if the standard bandwidth is between 20-40kbps (as we have demonstrated with a standard NoMachineNX-server/client). To sum it up, we want to move the Flash-applications, Java, and streaming applications (mplayer) from running on the thin client server, to run on the thin client. We want to surpass the Citrix-solution by taking the best parts from free software when reusing PC as thin clients. Some older PC are Pentium 133 MHz with 32 MB RAM, others are 450 MHz with 128 MB RAM. Our investigation is to put the "moving parts" on the client, and choke the bandwidth requirement between the server and the client. We want to show the ICT staff that it can be done even smarter than the Citrix-way, with give media-rich application a real life and user experience on the thin clients. They can choose. Do it the Citrix way, and you get less for your money. Do it the smart way, and you really get speed out of the newer reused machines. - Knut Yrvin -- Project manager (cel: +47 908 95 765) Skolelinux Norway and OpenOffice translation to Norwegian. Office 1: SLX Debian Labs Forskningsparken, Gaustadalle 21, 0349 OSLO, NORWAY. Office 2: IT-Staff Akershus County Council, Schweigaards gate 4, 0185 OSLO, NORWAY
