A key item in the MkIV upgrade of the EVN was the construction of the EVN MkIV data processor at the Joint Institute for VLBI in Europe (JIVE). JIVE is hosted by ASTRON in Dwingeloo, the Netherlands, and is funded by science councils of a number of European countries. Special projects have been funded directly by the EU. The EVN MkIV data processor [1], [2] was constructed in the context of the International Advanced Correlator Consortium through which the other MkIV geodetic correlators were also built, with significant contributions, from European members, in hardware from CNR/IRA, control software from Jodrell Bank, and correlator software from ASTRON.
The first fringe on the EVN MkIV data processor was seen on 21 July 1997 [3], and its official inauguration took place on 22 October 1998. The ``first science" resulting from data correlated on the EVN MkIV data processor detected HI absorption against the counter-jet very close to the nucleus of NGC4261 [4]. The first paper to be published in Nature based on EVN observations correlated at JIVE has also appeared [5], which uses OH mega-maser emission to study the kinematics and spatial structure of the circumnuclear torus in Mrk231.
The EVN MkIV data processor now correlates the vast majority of astronomical EVN experiments, and about half of the global experiments. Here, we will concentrate on areas of interest to the user having data correlated at JIVE: tools for planning observations with regard to the data processor's increased capabilities, current operational and communication flow between JIVE and the PI, and what we at JIVE do to get your data to you in a usable form. More information about using the EVN and JIVE can be found at the websites www.evlbi.org and www.jive.nl. We conclude with a look towards the future in terms of disk-based recording (Mk5) and linking the stations to the correlator via fibre (e-VLBI).