From: mark@taylor.uucp (Mark A. Davis) Subject: Re: X terminals: Suggestion for projects like SLS, MCC, etc. Date: Wed, 16 Jun 1993 13:46:43 GMT
ben@rex.uokhsc.edu (Benjamin Z. Goldsteen) writes:
> While I have to agree with Mark Davis about a few things, I think
>these numbers need to be fixed up.
>mark@taylor.uucp (Mark A. Davis) writes:
>>>How much does your 'host' cost -- the thing that's got all the disk and
>>>RAM necessary to support your X terminals? More than $400? More than
>>>$4000?
>>The host costs roughly 50k
>>Well, I would look at it more like this:
>>100 PC's x $1500 = $150,000 + OS's, config's, etc of $50,000 = $200,000
>>1 super micro + OS, config, etc of $50,000 + 90 text terminals @ $400 +
>>10 X terminals @ $875 + SERVER at $400 = $95,150.
>>We could come up with all kinds of numbers depending on what the requirements
>>are. I have a flexible configuration to support a wide variety of displays.
>>This cuts costs.
> Hmm -- 100 $1500 PC's versus 90 text terminals? I can not even
>find a 286 anymore -- the cheapest PC's I can find are 386SX-33's. They
>are much faster than a text terminal at text work, and they can do
>graphics (at $400/dumb terminal, you are not doing graphics).
Faster in what regard? They can display information faster? Not true on
a moden text terminal. If the users don't need graphics, then why spend
lots more money and worry about more upkeep? That was part of the point.
> I am not sure what the specs are on the $875 X terminals are, but I
>assume they are 14" B&W 70K Xstone X terminals. I assume the $1500 PC's
>up there also have B&W monitors (good B&W monitors ones are under $200).
They are 15" over 80K Xstones (the ones I use). Correct, the other money
is going to software, OS, Ethernet card, etc...
> Also, to get a server equivalent of the power in 100 PC's
>(adjusting for multitasking) you need at least 150 SPECs.
That is not true. In a multi-user multi-tasking environment not everyone is
using the power of the host as the same split second. So when load is normal,
or light, each user has access to most of the power of a fast host. During
heavy loads the multiple CPU's kick in. During very heavy loads is the
only time things start to degrade some. But this is rare if the host is
carefully configured. (At least here it is)
>You also need quite a bit of RAM.
yes, in one place rather than scattered as much over a distributed net.
But it is usually (overall) quite less because since everything is running
on the host you only need to have one copy of the OS, and each running
application.
>For this solution to beat the cost of the PC
>solution, we have average less than $600/X terminal or $60,000.
Perhaps there, but not here. Like I said, the numbers can vary wildly
depending on what your objectives are and what the envionment is like.
> The dumb terminal solution (dumb terminals can be X based) are MUCH
>cheaper if your users tend not to use their computers, though (because
>then you do not need as good a host).
True, part of the wildly varying environment I was talking about. But
we do make active use of perhaps half to 3/4 of all our terminals at any
given moment during business hours.
> My basic problem with this solution is that it uses up all its
>bandwidth for day-to-day operations. That is, he is now utilizing 4
>Ethernets. What happens when we want to do teleconferencing or imaging?
>You are just not going to get 10 people doing full screen visualizations
>over Ethernet at the same time. When you have to bring in the SGI
>workstations, does your scheme go to poop (that is my problem with one
>vendor solutions -- if your vendor does not provide it, you are
>screwed)?
Can't really address that. Don't have enough experience with using
ethernet for non-data purposes. I suppose it could be a problem. But I
don't find any flooding of the ethernet. Although there will be a lot of
activity, it is very small and often. With distributed systems (especially
diskless) the activity is less frequent, but there is a lot more info
being transfered (files, meaning more collisions).
> The X terminal solution is probably more cost effective when you
>add everything in (including people time), but it may not be flexible
>enough. There are advantages and disadvantages as he has noted many
>times. I like the distributed solution because it offers empowerment,
>but as he has noted, his users do not worry about backup's, archiving,
>etc.
I think they can be a good part of either system: distributed or centralized.
Xterminals are nowhere near as flexible as workstations. If this is a
problem for any particular environment, then they should NOT be used.
>--
>Benjamin Z. Goldsteen
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