Use the size of the virtual common service area (CSA) and extended CSA, defined by the CSA= parameter in the IEASYSxx parmlib member, as the minimum size for the common page data set. If the system is IPLed with a specification of CSA=(3000,80000), then the total CSA specified is 83000 kilobytes (approximately 81 megabytes). However, CSA and extended CSA always end on a segment boundary, so the system may round the size up by as much as 1023 kilobytes each. That rounding could make the CSA size as large as 83 megabytes with the CSA=(3000,80000) specification. After the system is running, you can use RMF™ reports to determine how much of the common page data set is being used and adjust the size of the data set accordingly.

Therefore: From the tables, 118 cylinders on a 3390 are needed to start with an 83-megabyte common page data set.