HostDrive is an application and development system enabling combined access to file resources for mainframe and network applications. HostDrive might be use in 2 different modes of operation. The difference between these 2 modes is the physical location of the concertedly used files. These may reside in the network or on the mainframe, respectively. The figure shows the HostDrive infrastructure that's used if direct access to network files is enabled to mainframe applications.

In order to use HostDrive in the shown mode the only prerequisite on the mainframe is the presence of some XPS adapter programs in the development and runtime environment which are are part of the HostDrive distribution. These adapters process the API calls executed by the application program, e. g. a call to read a file, by transmitting the request over TCP/IP to the HostDrive servlet.

For the HostDrive servlet to be executed, a Java Servlet Engine needs to be available. This may be any of the freely available engines such as Tomcat or Jetty. Or this may be part of one of the well known application servers. Within the scope of the HostDrive configuration symbolic names can be used to identify network directories. Mainframe programs can then use these symbolic names to access resources on the mapped directories. Through this abstraction there will be no maintenance effort for the mainframe programs if affected files are moved within the network. In these cases it's sufficient to adjust the symbolic names.

In the second mode of operation the mainframe will be used as data store location. In this case a hierarchic file system developed by XPS which is based on VSAM RRDS will be used. A mainframe program using HostDrive functions needs not to be aware of the fact if data is stored in the network or on the mainframe. In the latter case HostDrive requests will be processed by XPSDaemon - a VTAM application developed by XPS which maintains the hierarchic host drive and functions as TCP/IP server. In order to enable network applications to access files stored on the mainframe disk the HostDrive servlet offers a WebDAV interface. This enables the HostDrive disk to appear as a logical drive in the network infrastructure.

• Available for z/OS, OS/390, MVS/ESA, z/VSE, VSE/ESA
• Direct access to network files from mainframe applications
• Provision of a hierarchic drive on the mainframe being accessable for network applications through WebDAV
• Provision of an API for CICS-, IMS- and Batch programs in order to use HostDrive from mainframe applications
• Supported functions
  • List directory content
  • Create directory
  • Remove directory
  • Read file
  • Write file
  • Delete file
  • Copy file
  • Rename file
• Implicit translation while reading and writing data from the host through provision of a code page in the API call