200 computers would work fine from one server. There is no need of a server per year group....thats simply rediculous.
The fact is that initially all the computers will work off one server, since we don't have the cash to do any better, however I don't think it's as ridiculous as you suggest. It can distribute the load across network segments and, since the server won't (can't!) actually be any faster than my desktop machine, and I can easily saturate the hard disk IO on my own machine when working on various multimedia things, I'm sure that 200 kids doing not quite such adventurous stuff should be able to make a big dent in the performance of the machine.
And seeing as you seem to need NT/2000 servers for language lab et al then this/these may as well be for the whole school.
The point in the language lab is that the proprietary language software has to serve up multiple channels of streaming media to it's 30 machines. I think that would take a big chunk out of the available performance of that box, and leave the rest of the school poorly served when that machine was busy - if it was the only server.
I would _strongly_ recommend a PDC/BDC pair as if one should fail its easy to rebuild a new server from scratch and add it to the existing domain.
If you've ever tried to recover a domain server on different(new) hardware from the original that failed then you'll know what I mean.
I don't plan to use NT as a domain controller unless someone can come up with a good reason as to why I should.
Disc access/speed is OTOH criticial and UW2 fast spin SCSI drives are essential - ideally in RAID configuration.
I think that multiple servers running IDE RAID and loads of RAM will give me far more bang for my buck than a single machine with SCSI storage.
I'm sure the whole lot - including the NT domain could equally well be served by a LINUX box (even a single box...) although I would be inclibed to run the Email/proxy on a separate box (even if I was using NT)
We already have a fairly elderly machine doing the proxy job, but it is more than capable of coping with the 2Mb line which is supposed to arrive real soon now honest. The authority provides and manages webmail for all staff and students so we don't need to provide for it. Since I originally posted the school has scrounged nearly 200 bare machines (200MHz PII) so the network load has just gone up, but I suspect the days of the Acorn machinery (especially the pre Risc PC machines) are numbered. Cheers -- Phil Driscoll