Very topical discussion as I am currently designing (from scratch) an
application that will have to scale to be a distributed application.
Perhaps I simply don't understand them, but to my mind DCOM/Corba and
MIDAS are all overly complex solutions with big learning curves.
When I simply want an application to send messages to another
application (maybe on the same machine or across the world), to advise
of an event or pass a packet of data, I think building a solution around
UDP or similar IP technology (HTTP?) seems more intuitive. You can see
the idea working every time you use the WWW.
What I would like is a nice light weight framework that you can specify
the messages and/or data payload between software components and have
the framework deal with the issues of checking that packets arrive and
are error free.
For the record the app is designed to have 1 or more modem handling
components that may be distributed around the world but send incoming
files to 1 or more processing/db engines. Anybody know of any
off-the-shelf solutions?
Grant Black
Software Developer
SmartMove (NZ) Ltd
Phone: +64 9 361-0219 extn 719
Fax : +64 9 361-0211
Email: [EMAIL PROTECTED]
> -----Original Message-----
> From: Eliot Muir [mailto:[EMAIL PROTECTED]]
> Sent: Wednesday, April 21, 1999 11:23 PM
> To: Multiple recipients of list delphi
> Subject: Re: [DUG]: How thin the client will be?
>
>
> Call me a conservative....but why bother with all these
> proprietary networking stuff? Bound data
> type controls are renowned for making unscalable applications - the
> little bit of time saved in throwing apps together is usually
> absorbed in the
> maintenance and slow performance that these complicated technologies
> result in - especially when they don't work.
>
> DCOM and CORBA etc. don't achieve what they are supposed to - which is
> transparent operation of applications over networks. I
> haven't used MIDAS to
> be
> honest but I bet it's not the magic panacea that the spec
> sheet describes.
>
> The best approach is also the simplest. Implement your own simple
> client-server library
> based on on straight TCP/IP or maybe RPC, stream over some
> type of hash table
> object with a
> version numbering scheme, and get your server to decipher the
> calls and talk to
> the
> database.
>
> The advantages are that it's transparent - you know exactly
> when and what data
> is being
> sent across the network. It's easy to debug, you have
> complete control so it's
> easy to optimise
> - you don't have to spend heaps of time evaluating crap third
> party products
> which don't work.
> And lastly no license fees or danger of your client-server
> architecture
> becoming obsolete if
> the product you used gets dumped or the company which makes
> it goes under.
>
>
> Yanbo Li wrote:
>
> > Thanks Nic, dbOverNet licence sounds much cheaper than Midia.
> > I will contact with them.
> > I've already developed a Midas prototype. But the licence is too
> > expensive, we have to get rid of it.
> >
> > -----Original Message-----
> > From: [EMAIL PROTECTED]
> > [mailto:[EMAIL PROTECTED]] On Behalf Of Nic Wise
> > Sent: Wednesday, April 21, 1999 9:23 AM
> > To: Multiple recipients of list delphi
> > Subject: Re: [DUG]: How thin the
> client will be?
> >
> > have you thought about using dbOverNet?
> > www.dbovernet.com - same idea as MIDAS (which, IMO, is your
> best option,
> > tho it IS expensive), but I'm guessing their cost structure
> is a little
> > different :)
> > N
> > Yanbo Li wrote:
> > >
> > > Thanks, Your information is very helpful.
> > >
> > > Cheers
> > > Yanbo
> > >
> > > -----Original Message-----
> > > From:
> > [EMAIL PROTECTED]
> > >
> [mailto:[EMAIL PROTECTED]] On Behalf
> > Of
> > > [EMAIL PROTECTED]
> > > Sent: Tuesday,
> April 20, 1999
> > 2:14 PM
> > > To: Multiple
> recipients of
> > list delphi
> > > Subject: RE:
> [DUG]: How
> > thin the client will be?
> > >
> > > IB Objects and
> FIB components
> > rep[lace the BDE for
> > > Interbase but you still
> > > need the IB Client.
> > >
> > > DCOM is not necessarily
> > Windows only... but if you can
> > > find anyone who nows
> > > how to get DCOM for Mac or
> > DCOM or Solaris working then
> > > you are doing well.
> > > It's hard enough to get it
> > going on NT!
> > >
> > > You could use JBuilder and
> > Corba for the server end
> > > too...
> > >
> > > Peter Harrison IT
> > <[EMAIL PROTECTED]> on 20/04/99
> > > 14:45:54
> > >
> > > Please respond to
> > [EMAIL PROTECTED]
> > >
> > > To: Multiple
> recipients of
> > list delphi
> > > <[EMAIL PROTECTED]>
> > > cc: (bcc: Peter
> > Jones/Logistics&Information
> > >
> > Technology/Christchurch/Foodstuffs)
> > > Subject: RE:
> [DUG]: How
> > thin the client will be?
> > >
> > > Using standard Delphi the
> > TQuery requires the BDE to be
> > > installed, along
> > > with the database
> client of
> > choice. You don't mention
> > > the database
> > > type, so lets
> assume we are
> > talking Interbase. You will
> > > need to install
> > > the Interbase
> Client on the
> > client machines, the BDE,
> > > and your
> > > application.
> > >
> > > This is not
> 'thin' client in
> > the least.
> > >
> > > If you want to
> use Interbase
> > you havn't got much choice
> > > about any of
> > > this, except that
> you might go
> > with a product which
> > > replaces the BDE
> > > with a driver
> specifically for
> > Interbase eliminating the
> > > need for the
> > > BDE (do these exist?)
> > >
> > > If you want to go
> with File
> > Based Databases, such as
> > > dBASE, you can
> > > probably eliminate the
> > database client and bde, and have
> > > a single app,
> > > and perhaps a DLL or two.
> > 'Apollo' is an example
> > > product for this
> > > approach.
> > >
> > > Besides the n
> tier stuff there
> > isn't much alternative.
> > > You could always
> > > start writing
> DCOM interfaces
> > - conceivable by really
> > > ugly - and Windows
> > > dependant.
> > >
> > > Good luck...
> > >
> > > -----Original Message-----
> > > From: Yanbo Li
> > [mailto:[EMAIL PROTECTED]]
> > > Sent: Tuesday,
> April 20, 1999
> > 1:10 PM
> > > To: Multiple
> recipients of
> > list delphi
> > > Subject:
> [DUG]: How thin
> > the client will be?
> > >
> > > Many thanks in advance.
> > > I need to know
> how thin the
> > application will be if I
> > > only use TQuery
> > > and TDatabase to
> connect to
> > remote server. If the app is
> > > still very fat,
> > > I have to manage
> to write my
> > own driver which I am not
> > > found of. Please
> > > do not suggest me to use
> > TClientDataSet and 3tier
> > > technology.
> > >
> > >
> >
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