when is host based architecture appropriate?

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Request for Question Clarification by maniac-ga on 14 Jul 2003 20:17 PDT

Hello Barryr,

Are you still looking for a answer to this question? If so, please
respond with a slightly longer explanation of what you are looking
for. For example, a comparison of "host based" to "client/server", or
some other description. If not, I suggest you close the question so
you won't be billed for an answer you don't need.

  --Maniac

Dear BabyRay, 

Host based architecture (as coined by Fitzgerald and Dennis), as a
stage of converting input into output, is a stage of centralised
processing, whereas all computer data processing occurs at a single
site. In this type of processing, the main computer does all of the
work and is therefore more secure (relatively) prevents abuse of the
system.

Host based architecture is relatively old and is the older technique
of processing.

When is it appropriate? When you need a lot of security, and you want
to avoid any possibility of external threats on the stations. It may
also be appropriate in schools (for examples), workplaces, jails,
libraries and other public computers, where you don't want the users
to engage in any other activity other than the one these computers
were intended for: not to download, chat, use the applications other
than to work purposes, etc.

However, this has a lot of disadvantages that must be considered. The
host must perform all actions, which may imply that it will work
slower, that the upgrades and will be much more costly. Some of these
problems could be solved using intelligent terminals and PC emulation,
as well as pseudo conversations programming methods, like CICS. (See:
Jack Messinger, "Application Layer - Fitzgerald/Dennis Chapter 2 - 7th
edition (class 3)" http://disc.cba.uh.edu/~jake/classes/disc4377/notes/chapter2.html).

Further Reading
===============
1. Fitzgerald, Dennis: Business Data Communications and Networking,
7th edition, p. 43.

2. "Introduction to Data Communications"
http://www.businessfaculty.utoledo.edu/ahmed/FD7Ch2.ppt (Power Point
Presentation).

Search terms: 
"host based architecture"
host processing architecture dennis fitzgerald

I hope this answered your question. Please contact me if you need any
clarifications on this answer. I'd be pleased to clarify my answer
before you rate it.

By host based architecture I assume you mean a "dumb-terminal" type
system like VT100 / IBM 3270.

These systems contain all of their data access and functions on a
central computer which means that network performance has little or no
bearing on processing times. The network is used simply to transfer a
screen buffer to the "dumb terminal" removing the network as a
variable in the performance equation.

This can also be a more secure and easier to tune environment and
there is no programmatic access to the host from the terminal or
workstation.

On the other hand the move to distributed computing happened so that
the local processing power could be exploited by the end user and
smarter user interfaces could be provided.