Upgrade plans to handle 30 to 40 Mbytes of data for DIII-D

The DIII-D tokamak began operation in February 1986. At that time, approximately 7 Mb of data was collected for each shot. The average shot size is now about 26 Mb, and over 1 Gb of data has been collected during some operation days. The computer systems were designed to handle a maximum shot size of 25 Mb. In order to meet the increased demands, changes to hardware and software are being made and each experiment reviewed before being added to a shot. The largest increase in data transfer is from small diagnostic DEC VAX systems to the main VAX cluster. Plans in this area include upgrading the VAX which receives data (possibly to a VAX 6310) to have more CPU power and a faster interface to the Network Systems Hyperchannel which transfers data to the VAX. The new machine will be more easily upgraded with additional CPUs, communication devices, and storage devices. Software changes are being incorporated on diagnostic VAXes so that subsets of data or calculated results are included with the shot data file, rather than the often large (6-20 Mb) amount of data collected locally. More careful examination is being given to all experiments added to the tokamak, and only necessary and useful data is being added to the system for permanent storage