[K12OSN] Slow terminals

"Terrell Prudé Jr." microman at cmosnetworks.com
Mon Aug 6 17:07:35 UTC 2007

rmiller at seminole.k12.ga.us wrote:
> I've got two 5.0EL labs set up that we're using to test out the viability of using LTSP in our Elementary School and possibly in our Middle/High School as well. So far, the feedback has been mostly positive.
> I've got 2 issues that are causing some reservations by the teachers. One is that the terminals are a little slow, especially whenever a student exits a program and tries to go back into it. The servers are struggling to keep up. Eventually, they will get back into their desired program, but not before they've clicked it several (dozen) times.
> I'm thinking that my servers may not have enough ram, but I need more feedback from you, the more experienced. Both labs are running an HP xw6000 server with a 3.2 Ghz Xeon processor, 4 GB of ram, dual 30 GB SCSI hard drives. There are 28 terminals in lab and 26 in the other. I have gigabit nics in the servers going to an HP 2650 switch (GB uplink port, 48 100MB ports). I would think a 3.2 Ghz Xeon would have the capacity, but what about doubling the ram to 8GB? Any suggestions would most definitely be appreciated.
What kind of switches are you using?  You mention Gbit on the server,
but are you sure that your clients are autonegotiating to 100Mbps/FDX? 
If not, that can cause some slowness.  That said, even 10Mb/Half Duplex,
as experienced on my ancient Power Mac 5260 is at least tolerable for
launching OpenOffice.org.  I've run 25 terminals on a 4GB (well, 3.5GB
usable) dual Athlon 1.47GHz box with twin 80GB EIDE disk drives with no
slowness whatsoever, *and* that server was one of the main file servers
for the entire school (Samba).

Speaking of Gbit on the server, are you seeing any errors on that switch
port--CRC, input, or otherwise?  And is it all clients, or just certain

One other thing to look at is what top says.  Are you indeed running out
of DRAM, do you have some process that's eating up either memory or disk
I/O?  When this happens, are your disk drives thrashing like crazy?

> The other issue relates to one of the 2 labs. In it, I have 26 Acer 220 laptops. I boot them off a boot floppy as PXE doesn't seem to work on them, but that's another issue. The biggest problem I'm having with them is at that I running them at 800x600 (most I can get), and some of the games, i.e. ChildsPlay, is shifted to the right so that about 1/3 of the screen is not visible. If they were standard desktop pc's and monitors, I could adjust the monitor's settings to move the screen to the left. Can't do it on the laptops. If you have any suggestions on this matter, I'd also appreaciate any help. 
Try running ChildsPlay in a window instead of full screen, like this:

    microman at takhisis ~]$ childsplay --window


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