NIH opens mainframe access
- By Florence Olsen
- Feb 22, 1999
Web-to-host access software has come along at the right time for Tim Barnes, branch
chief at the National Institute of Allergy and Infectious Diseases.
Barnes, who heads the Intramural Technical Systems Branch, wants to put his Macintosh
and PC users on an equal footing to search the institutes IBM IMS mainframe
We have a couple of gateways to the mainframe, Barnes said, but they work
only for PCs. He thinks a Java client application that runs on both PCs and Macs might
solve his host access problem.
The software he chose for evaluation is the Hummingbird HostExplorer thin client, which
provides multiplatform Java-based TN3270E mainframe connectivity through HostExplorerWeb,
a Web-to-host server from Hummingbird Communications Inc. of Mountain View, Calif.
Were looking for some way to set up [Web-to-host] on our intranet so we
dont have to keep versions of 3270 software on the workstations, Barnes said.
As the official responsible for 1,100 user systems, Barnes is interested in a scheme
that would let the users simply hit Active Server Pages under Microsoft Windows NT to
upgrade their host-access software. Thats a pretty big deal for us, he
Most systems managers evaluating Web-to-host solutions are looking for a way to extend
host access to a larger user base, or to reduce their management costs and training time,
said Dave Trowbridge, Hummingbird Communications marketing manager.
In configuring Web-to-host access, administrators must define user host profiles,
network permissions and systemwide defaults, Trowbridge said.
The Hummingbird server runs under Windows NT 4.0 and manages Java client applications
as well as standard client applications. On the fat clients, a Java daemon lives in
the PC and starts up every time the PC starts, Trowbridge said.
The Java applet in HostExplorer exploits Java multithreading. Users see no performance
difference between the Java applet and the standard client application, he said.
Once the server delivers functionality to the desktop as a Java applet or ActiveX
app, it gets out of the way, and the connection is direct to the host, he said.
The Hummingbird HostExplorer thin client handles 3270 connectivity but not printing,
If users want to do more than just view the data in IMS, he said, they must be able to
use the print functions in their Windows desktop applications.
Trowbridge said security is improving for users of Web-to-host access products now that
Java programs are replacing the older Common Gateway Interface programs.
Unless you specifically parse the input from a CGI form and allow no more than 40
characters, a hacker could throw in a command on buffer overflow and take over your
computer, he said.
Hummingbird will write additional security modules for its Web-to-host server if
customers ask for them, Trowbridge said. If they want Secure Sockets Layer or
public-key infrastructure and are willing to deal with the scalability issues, well
do it, he said.
He said users who want to access a host via the Web start by entering a universal
resource locator in the browser. The Web-to-host access server then downloads an object
request broker applet, or orblet, into the browser, and an authentication screen pops up.
The user name and password are sent encrypted back to the access server, which passes
the user information to the Lightweight Directory Access Protocol for authentication. LDAP
checks the user profile and passes the information back to the object request broker,
which constructs the applet launcher.
The applet launcher is a Microsoft Internet Explorer-like interface that shows only the
resources a user is authorized to access. When the user clicks on one of the resources,
the appropriate applet is downloaded and the user connects to the host.
A number of Web-to-host servers, including Attachmate Corp.s e-Vantage, support
the Open Host Interface Object (OHIO), a set of program interfaces for Web-to-host access.
IBM Corp. and Attachmate, which jointly developed the OHIO standard, have submitted it
to the Internet Engineering Task Force for adoption.
OHIO is our attempt not to have [High-Level Language Application Programming
Interface] wars this time around, said Doug Strohm, vice president of strategic
communications for Attachmate of Bellevue, Wash.
Components of Attachmate e-Vantage include the $4,995 host access server for Windows
NT; the $425 e-Vantage enterprise client access license, which includes the Attachmate
Extra Personal Client; and a $99 e-Vantage standard client access license for
Hummingbirds Java Management Platform (JuMP) HostExplorerWeb Server bundle
includes a $1,595 JuMP Server for authenticating users and launching applets, a Web server
and an LDAP server. The company also sells a $995 JuMP add-on for thin-client X server
Hummingbirds Jconfig software manages fat and thin clients, including the $319
Exceed Web Thin-X client and $149 HostExplorer Thin TN3270E/5250E/VT client for mainframe
and midrange connectivity.
Both companies plan to offer Unix versions of their Web-to-host access servers.
The jury is still out on Web-to-host access technologies, Trowbridge said. We
cant quantify it yet, he said, but theres a good chance we can
deliver the reduced cost of ownership that this technology is supposed to be about.
Contact Hummingbird Communications at 650-917-7300 and Attachmate at