FAQs

The following provides the answers to some frequently asked questions about Verastream Host Integrator:

General Questions

Modeling Questions

General Questions

What is the Verastream Host Integrator Development Kit?
The Verastream Host Integrator Development Kit provides an innovative approach to host systems integration and re-engineering, which requires no changes to the existing host systems and causes no interruption to the end-user operating environment. The Development Kit allows you to integrate host systems into client/server and World Wide Web applications 10 to 15 times faster than with traditional toolsets. New applications can be partitioned to support multi-tier client/server architecture and deployed across a wide variety of operating systems and hardware platforms.

The Development Kit offers a low-risk evolutionary approach to host systems integration, which can be defined in the following steps:

  1. Using the Design Tool, you can build a model of a host application by navigating through that application and pointing and clicking at the screens and fields representing data that should be integrated into a new application.
  2. Then, you store the model in a folder containing the .model file and any supporting files, which can be activated on the Host Integrator Server directly from the Design Tool.
  3. Then, using a Host Integrator API to access the host data stored in the model file on the Host Integrator Server, you can develop a new client/server or web application in order to build a GUI front end for the existing host application.


What are the Host Integrator components?

Component Description
aads Authentication, Authorization, and Directory Services server
AppConn Host Integrator connector classes and libraries to access sesssrvr
aws Administrative WebStation
hostemul Host Emulator
logmgr Log Manager
smonitor Session Monitor
sesssrvr Host Integrator Server

For a description of each Host Integrator component, see Host Integrator Components.

Which terminal types are supported?
The Design Tool is capable of connecting to any one of following hosts:

You can select a terminal type in the New Model dialog box or, after a model is loaded, in the Session Setup dialog box.



Which transports are supported?
Telnet, Telnet Extended (TN3270E), Telnet SSL, Telnet Extended SSL, and NS/VT.


Which host character sets are supported?
In the table below, there are pairs of code pages distinguished by Euro support, such as German and German + Euro. The Euro version of each pair reports that there is support for the Euro code page version to the host; the non Euro version can display the Euro, but does not report this to the host.

EBCDIC      
Country codepage 3270 5250
Austrian+Euro 1141 yes no
Austrian 273 yes no
Baltic 1142 yes no
Baltic+Euro 1156 yes no
Belgian (Old)+Euro 1148 yes yes
Belgian (New)+Euro 1148 yes no
Belgian 274/500 yes yes
Belgian (New) 500 yes no
Canadian French+Euro 1148 yes yes
Canadian French 037/260 yes yes
Custom N/A yes yes
Cyrillic+Euro 880 yes yes
Danish+Euro 1142 yes yes
Danish 277 yes yes
East Europe+Euro 870 yes yes
Finnish+Euro 1143 yes yes
Finnish 278 yes yes
French+Euro 1147 yes yes
French 297 yes yes
German+Euro 1141 yes yes
German 273 yes yes
Greek+Euro 875 yes yes
Icelandic+Euro 1149 no yes
Icelandic 871 no yes
Italian+Euro 1144 yes yes
Italian 280 yes yes
Multilingual+Euro 1148 no yes
Multilingual 870 no yes
Netherlands+Euro 1140 yes no
Netherlands 037 yes no
Norwegian+Euro 1142 yes yes
Norwegian 277 yes yes
Portuguese+Euro 1140 yes yes
Portuguese 037 yes yes
Spanish+Euro 1145 yes yes
Spanish 284 yes yes
Swedish+Euro 1143 yes yes
Swedish 278 yes yes
Swiss (French)+Euro 1148 yes no
Swiss (French) 500 yes no
Swiss (German)+Euro 1148 yes no
Swiss (German) 500 yes no
Swiss+Euro 1148 no yes
Swiss 500 no yes
Thai * 838 yes yes
Turkish+Euro 1026 yes yes
UK English+Euro 1146 yes yes
UK English 285 yes yes
US English+Euro 1140 yes yes
US English 037 yes yes


* Some Thai characters (cent symbol, the split vertical bar, and the IBM not symbol) do not display correctly in Design Tool dialog boxes that display text for patterns or filtered text. These characters can be input via the keyboard and are displayed correctly in the Design Tool terminal window. The Java, COM, and .NET connectors handle these characters correctly.

VT host character sets
DEC Supplemental
ISO Latin-1 (8859-1)
ISO Latin-9 (8859-15)
PC 437 (English)
PC 850 (Multilingual)
Windows 1252



HP host character sets
HP Roman-8
HP Roman-9

Modeling

Is it the connection or the applications that are block mode or character mode?
A combination of the host and the application it is running dictates block mode versus character mode. VT/ASCII terminals are always character mode. IBM AS/400 terminals, which use the 5250 datastream protocol, and IBM mainframe terminals, which use the 3270 datastream protocol, are typically block mode. HP3000 terminals can be block mode or character mode, but the combination of the host and the host application determine the type of connection that is needed.
What's the difference between scrolling operations in character mode applications and block mode applications?
Scrolling operations, such as page up or page down operations, are in no way unique to character mode or block mode applications. They are important for recordsets, but these types of screen constructs exist in all types of host applications that are accessible by Host Integrator. The only difference is that character mode applications require more specific recordset configuration since it is more difficult to determine when the host is finished sending recordset data after a query has been made.

Tip:
Use Model Debug Messages to view the real-time data sent and received from a host.
Are there any hard coded timeouts in Verastream Host Integrator or should I expect to be able to configure my own timeouts for settings and operations?
There are no hard-coded timeouts in the Host Integrator system. For example, you can configure timeouts for the host connection, global navigation, and "keep alive" inactivity in the Model Properties dialog box. Under Properties on the Operation tab, you can also configure a timeout for a selected operation. In addition, all of the Host Events commands provide timeout settings. If any timeout occurs in an operation, the whole operation is stopped—there is no "master timeout." For example, if a Host Events command has a timeout of 10 seconds, while an operation has a timeout of 30 seconds, they each get the full extent of their time until they complete or time out. Since there are so many potential timeouts in Host Integrator, and you must adjust them all appropriately.


How do I make the current entity an alternate entity or error entity?
See Troubleshooting Error Patterns and Error Entities for more information.


What is the difference between using the DefaultValue command and the TransmitToAttr command in operations?
DefaultValue implies that the value argument will only be written if the client has not provided a value already. If the behavior you want is to always transmit the value to the terminal, regardless of the API client code, then use TransmitToAttr.


What does the CheckOperationConditions command do?
The CheckOperationConditions command checks the required attributes and the condition string. The error patterns and the post-operation condition are evaluated separately. By default, a CheckOperationConditions command is added to every new operation.


What's the difference between error patterns and error entities?
Error patterns are often host messages that appear on the terminal screen when an error occurs during an attribute write. These types of messages are common when modeling character mode host applications. They cannot be part of an entity signature, but they can be contained in an operation condition. If an entity encounters an error pattern during an operation, a text or an attribute value can be returned. No action can be associated with an error pattern. An error pattern can consist of a particular host message or a non-blank host message.

Error entities are entities that only appear when a host error occurs. Error entities can be contained in operations destinations, and they can return text or attribute values in an exception. They cannot, however, be valid or intermediate destinations. Error entities should contain operations to move back to a navigable entity. Typically, the operation to move away from an error entity contains the logic to recover from the error, for example, a locked 5250 terminal can be released by pressing the Reset key. An error entity can be as simple as a copy of some other entity, when the host message line is non-blank.

Error entities typically have an action associated (an operation to get back to a navigable state), while error patterns cannot contain an action. For more detailed information, see Troubleshooting Error Patterns and Error Entities.



How and when are error patterns detected?
Error patterns are registered with the Host Integrator Server scanning component when the operation begins. At any time during the operation that a scan is performed (new data from the host is the usual reason a scan is performed), then the operation can trap the error pattern. If the pattern is already present before an operation starts, it would not be recognized.


What about tables and error entities?
If you are using procedures you can choose to add an error entity to your procedure although defining error entities is not necessary if you've already defined them in your operations.

Note:
If you insert error entities into your procedures, you will not be able to use the custom error messaging option available when defining error entities within your operation. Instead, you have to define a custom error message within the Procedure Editor. Additionally, the error message feature within the Procedure Editor does not allow you to assign the contents of an attribute to the error message.


What about tables and error patterns?
If you are using tables and error patterns, you don't have to modify anything within your procedures.
How can I fix the trailing spaces problem?
If you have a procedure that requires that you send data to a numeric field (format: #####.##) and enter the value 6, for example, you may find that the application will not accept your input. Running a trace reveals that instead of sending just 6, Host Integrator is sending 6 followed by 7 spaces. The spaces are wiping out the 6 and the result is an error.

On the Attribute Properties tab, clear the Erase to end of attribute check box associated with writes.