HostDrive is a platform comprehensive queing system which makes possible the automated data exchange between various platforms especially providing support for IBM mainframes.

HostDrive constist of two software components which implement the queuing functionality in cooperation. On the mainframe this is realised using HostDrive/z, a VTAM application based on the same kernel as e. g. PrintEx, the mainframe print services extender from XPS. The network component is called HostDrive/J, a Java server program.
HostDrive/z has to be launched in an own region under z/OS and in an own partition under z/VSE. Due to the fact that the TCP/IP protocal as well as VTAM protocol are supported, HostDrive/z as a matter of principle is able to forward data from and to virtually any mainframe sub system.
A number of APPC CICS adapter programs are shipped as part of the HostDrive/z installation package. These can be used without further adaption e. g. to read and write data to CICS/TS, CICS/TD as well as VSAM/KSDS and VSAM/ESDS. Besides these more pre-assembled interfaces are available e. g. to access library members under z/OS and z/VSE respectively.

HostDrive/J can be executed on any Java-enabled platform having a Java runtime environment version 1.6 or better running. No other infrastructure is necessary in order to launch HostDrive/J. Especially HostDrive/J doesn't rely on any underlying application server. Besides the possibilities to communicate with HostDrive/z mainframe installations and with other HostDrive/J server installations, HostDrive/J supports communication over various standard technologies such as FTP and JMS.

In order to provide queuing functionality both programs adapt technologies suitable for the underlying operating system. HostDrive/z stores data which cannot immediately be delivered because of the non-availability of the target system as long as necessary in a hierarchical disk implemented on top of VSAM/RRDS. As soon as the target system is available again, data will be delivered to it in chronological sequence. To achive the same goal HostDrive/J makes use of the file system of the underlying operating system.