te07@edrc.cmu.edu (Thomas Epperly) (11/17/89)
I am considering adding 3 X terminal, probably from NCD, to a DECstation 3100 with 8meg of RAM. I am wondering how good of an idea this is. I would like general comments in addition to answers to some specific questions. 1) What kind of resources will the X terminal use on the DECstation? Specifically, will it need disk space(how much), RAM, and CPU? 2) How much of a CPU burden is an X terminal? 3) How do you login to/through the X terminal? Do you have a login screen or do you have to "telnet" to the DECstation? 4) Are there any specific aspect of the DECstation that might effect the instalation/performance/functionality of the X terminal? You recommendations and responses will be appreciated. Thanks in advance, Tom Epperly
klein@lupine.UUCP (11/17/89)
(Disclaimer - Since I work for NCD, I obviously am not unbiased towards
NCD displays, but since I use a configuration every day very similar to
what you describe, I think I can add some useful insight :-)
I am considering adding 3 X terminal, probably from NCD, to a DECstation
3100 with 8meg of RAM. I am wondering how good of an idea this is. I
would like general comments in addition to answers to some specific
questions.
1) What kind of resources will the X terminal use on the DECstation?
Specifically, will it need disk space(how much), RAM, and CPU?
The only disc space required by an NCD above and beyond that used by a
normal user is < 10 mbytes for boot images, fonts, and configuration
information. Trivial, really, compared to what 'user files' would most
likely take, or /usr/bin. CPU usage is *very* application dependant. A
good developer can bring *any* computer to its knees - how many 'make's
can you type in 60 seconds? In our particular environment, though, we
have *plenty* of cpu power to keep 8-12 users going. (We use the
machine for general 'office automation' use; i.e, word processing,
mail, occasional compilation, etc.) We have found, however, that X
users tend to be much happier when the host has *plenty* of RAM,
though. In our environment, we run 16 mbytes of RAM and are happy, but
if I added any more users to this system, I would bump it to 24 mbytes.
For an additional 3 users to a DECstation you should be able to get
away with 8 mbytes of RAM, but after playing with this system and a
good variety of other of the current 'hot' UNIX hosts, I wouldn't even
consider trying to run UNIX (I don't care whose) on anything less than
16 mbytes. Bottom line on RAM - trust me, buy more!
2) How much of a CPU burden is an X terminal?
I would make the argument that the 'CPU burden' of an X terminal is
noise when compared to the overhead of multiple users running multiple
applications. I wouldn't be so concerned about 'X overhead' (whatever
that might be), but I would think seriously about what applications the
user's will be running. Are they all running 8 hour finite element
analyses? Are they simply logging in once and a while to read their
mail? We have one programmer that can bring our Sun 4 *completely* to a
standstill, but at the same time I can run 20-30 users on a lowly
microVAX 3500, all very happily reading their mail! It ain't X causing the problem!
3) How do you login to/through the X terminal? Do you have a login
screen or do you have to "telnet" to the DECstation?
There are a variety of ways to get started with X terminals. Most
support a separate 'telnet' session that allows you a way to initially
connect to the host and kick off some X applications. Most will be work
with an MIT supplied client called 'xdm', (the "X Display Manager"),
some more elegantly than others.
4) Are there any specific aspect of the DECstation that might
effect the instalation/performance/functionality of the
X terminal?
The only specific aspect of a DECstation that I know of would be
DECwindows itself. There are some finer points in making this work that
you might want to know about. If this is of interest to you, let me
know, otherwise I'll leave this for another discussion, some other time.mouse@LARRY.MCRCIM.MCGILL.EDU (der Mouse) (04/08/90)
> I am trying to do some work on X terminals. I have some questions > reagrarding the CPU that get used in a X terminal application. > I believe that in a typical X terminal application the server > executes on the terminal and the clients on the host. Yes. There are some minor exceptions, like GraphOn, which runs part of the server on the host, and someone's X terminal which has some of the most common clients built-in, but in general this is true. > The CPU which is on the terminal is basically doing two jobs: 1) > communicating over network and displaying data on the CRT. Well, an X server is more than just an interface between the network and the screen. It also has to handle off-screen storage (pixmaps, primarily) and keyboard/pointer input.... > Now I have following questions regarding X terminals. > 1) How of the code that is running on the terminal is TCP/IP server > code ? (Assuming you mean "How *much* of the...") Never having seen source to an X terminal, I have to guess. But I have seen code for an X server (the MIT one) and to TCP implementations (the Van Jacobson code, for example). Comparing the handiest examples of X servers and TCP code produces a count of 7962 lines for TCP/IP and 101024 lines for the X server. > 2) [...] > 3) [...] I have not even a guess for those. der Mouse old: mcgill-vision!mouse new: mouse@larry.mcrcim.mcgill.edu