See source.

The CDC 6400 was upgraded to a CDC 6500 in 1969. This image, taken on 12 February 1974, shows a general view of the remote input/output station installed in building 112, used for submitting jobs to the CDC 6500 and 6600. The card reader on the left and the line printer on the right are operated by programmers on a self-service basis.

A Data Handling Division report by Philipe Bloch states:

Around the CERN sites more than 150 computers of widely varying sizes are installed. They vary from small mini-computers (PDP8, HP2115A) via larger mini's and control computers (PDP11/45, HP4100, Nord-10, IBM1800, Modular One, Ferranti Argus 500) over medium sized computers such as PDP-10, IBM-360/44, CII 10070 and CDC 3200 to very large computers (CDC 6600, CDC 7600) in the Computer Centre itself. Many mini-computers are used by experimenters for data collection but accelerator control, remote batch stations and process control application use most of these. The medium sized computers are normally dedicated to particular types of processing for individual groups or divisions: measurements of bubble chamber pictures (CDC 3200, ERASME on the PDP-10), support for data collection for the OMEGA spectrometer and the Split Field Magent (CII 10070). 

The Computer Centre is part of the Data Handling Division and provides a general purpose scientific computing service to both Laboratories... About 700-800 different users run approximately 15,000-20,000 jobs per week on the main computers and mount about 4000 tape reels from a total tape library of more than 6000 reels. Remote batch and terminal services as well as high-speed data links and a delivery service make computing easily accessible practically everywhere on the site round the clock. 

The following is an extract from: "The LHC computing grid project at CERN" (Lamanna, 2004)

The first service of the LHC Computing Grid, called LCG-1 was opened on September 15th, 2003, with 25 sites worldwide. In this phase, the goal was to allow the experiments to try out the system and test their software on it. Although incomplete in functionality, in particular, due to some limitation in the data management interface to tertiary storage, LCG-1 is demonstrating very good stability and serving as a basis for the users to prepare for the 2004 data challenges.

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The aim of the European Datagrid project was to produce a "production quality" computing Grid, in anticipation of the construction of the Worldwide LHC Computing Grid. According to the project's website:

The objective is to build the next generation computing infrastructure providing intensive computation and analysis of shared large-scale databases, from hundreds of terabytes to petabytes, across widely distributed scientific communities

The project passed its third and final review at CERN on 19 February 2004. 

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CERN today signed a contract with the Wigner Research Centre for Physics in Budapest for an extension to the CERN data centre. Under the new agreement, the Wigner Centre will host CERN equipment that will substantially extend the capabilities of the LHC Computing Grid Tier-0 activities. This contract is initially until 31 December 2015, with the possibility of up to four one-year extensions thereafter.

“Installing computing capacity at the Wigner Centre allows us to power additional equipment as well as secure our operations due to the remote nature of the resources” said Frédéric Hemmer, Head of CERN’s IT Department. “For example, should we suffer a prolonged power cut at CERN, we will be able to transfer critical functions to the Wigner Centre, mitigating the risk of having all of Tier-0 in one location."

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At its 81st meeting on 16 February 1967, CERN's Finance Committee authorized the purchase of the CDC 6400 computer, a small CDC 3100, and four magnetic tape units. The costs exceeded the funds available in the 1967 budget by 7-8 million Swiss francs. In its next meeting the Committee recommended the use of CERN's own funds for the purchase, "only raising a bank overdraft if this is necessary to cover the cash requirements". 

The CDC 6400 was installed at CERN later that year. 

The Canton of Geneva bought the CDC 3800 from CERN, and installed it at the University of Geneva. At CERN, the CDC 3800 was replaced by a CDC 6400.