Microsoft Mainframe Architecture

A customer prompted me to review Microsoft Host Integration Server 2006's architecture. They're considering MS HIS as a replacement for their Novell NetWare for SAA branch office gateways. My question was, "Do you even need a gateway?" "No" appears to be the correct answer.

There's a basic fallacy at work here. If you pretend that there's nothing new in mainframe networking for at least the past decade, then MS HIS is one of several possible options. Otherwise, does anybody know what the point of this product is? I fear that a lot of customers are wasting their money.

Let's start with the money part.  For each branch you need an X86 server running Microsoft Windows.  Then you need a Microsoft Host Integration Server 2006 server license, at $2,499 per CPU.  Add a Microsoft SQL Server 2000 license to that.  Let's suppose you can get away with SQL Server 2000 Workgroup Edition and that you spend about $1,500 for one CPU plus 10 user licenses. (Let's assume your branch office has 10 users.) That's now $4,000 per CPU in software, excluding anything else you might buy for operational management. Multiply $4,000 by 500 branches and you've got a cool $2 million, although maybe Microsoft will cut you a special deal. Except you've got to add the annual support fees, and did I mention the hardware, installation, and your own burden for managing 500 remote servers? Talk about expensive!

What do you get for all that? Well, if when your branch server crashes, every client in your branch office is dead and cannot connect. (Then should you buy two for every branch?) If you ever decide you want to get rid of the Microsoft HIS servers because you're frustrated with the diminished service quality, sorry: "Customers cannot use the client pieces of HIS to connect directly to the host." (Even if you pay for the software!) You also get to write to proprietary APIs which nobody else except Microsoft has, like FMI (a.k.a. 3270 EIS), so you'll spend time and money trying to migrate in the future.

Or you can just...connect every client directly to the mainframe! With TCP/IP! You can buy SNA-related APIs on the client to support your existing code while maintaining TCP/IP connectivity across the wire, but you only buy that if you need it. (IBM products such as the CICS Universal Client, Personal Communications, and the Communications Server for Linux on z Remote API Client are examples, and there are others, including non-IBM products.) That's leaving aside capabilities such as Web services on the mainframe, HTTP on the mainframe, Java on the mainframe, etc.  Fun historical fact: Stanford University installed the first HTTP server anywhere outside of Switzerland, and it was on a mainframe.

So that's what this banking customer is going to do, connect directly to their mainframe. They just avoided a multi-million dollar mistake.

Is there a good use for Microsoft Host Integration Server 2006? What is it?

Minor spelling error corrected April 12, 2007.

by Timothy Sipples April 10, 2007 in Economics


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A great review on M$ HIS product. We have been set up M$ SNA server and HIS here for terminal emulator during the past years. But somehow it's hard to get tech support if something went wrong. But I've got one question which is if all the terminal connect through TCP/IP directly to the host. Will it be a extra consumption of host CPU? Thanks in advance for your kindly help. Regards,Mac.

Posted by: Mac Chen | Apr 13, 2007 2:25:09 AM

Microsoft Host Integration Server can connect to the mainframe in several ways, including (lately) Enterprise Extender, a TCP/IP protocol. If you're using HIS as a 3270 gateway, then it should be (to first and probably second order approximation) mainframe load-neutral if you shift that gateway function onto the mainframe itself. The mainframe still has to do basically the same work with basically the same path length. (Lately the TCP/IP path lengths are actually a bit better than the SNA ones.) I'm assuming relatively recent mainframe hardware and a relatively recent operating system level (i.e. past several years).

You can ask IBM for a sizing estimate. Just tell them what you're subtracting and what you're adding. For example, you might be subtracting 3270 via SNA (with or without Enterprise Extender) and adding TN3270E.

There was a discussion recently about this issue in the IBM-MAIN distribution list. If you do a Google search on that you'll find the discussion. It related to an original question asking about replacing Cisco CIP. The overwhelming consensus answer was, "Just use the mainframe itself." The same principle applies here. The same principle is also likely true for other possible HIS-mainframe interactions, such as MQ, CICS (ECI/COMMAREAs), etc. -- just go direct. Simple.

Posted by: Timothy Sipples | Apr 13, 2007 7:09:47 AM

i want to know completly about IBM MAINFRAMES ARCHITECTURE

Posted by: arshad ali | Jun 24, 2008 10:20:57 AM

I want to complete my MS in Mainframe

Posted by: siva ganesh | Sep 28, 2010 8:23:42 AM

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