With control interval access, you have the option of user buffering. If you use the user buffering option, you need to provide buffers in your own area of storage for use by VSAM.

User buffering is required for improved control interval access (ICI) and for PUT with OPTCD=NUP.

With ACB MACRF=(CNV,UBF) specified (control interval access with user buffering), the work area specified by the RPL (or GENCB) AREA parameter is, in effect, the I/O buffer. VSAM transmits the contents of a control interval directly between the work area and direct access storage. If ACB MACRF specifies UBF, only one CI may be read or written.

If you specify user buffering, you cannot specify KEY or ADR in the MACRF parameter; you can only specify CNV. That is, you cannot intermix keyed and addressed requests with requests for control interval access.

OPTCD=LOC is inconsistent with user buffering and is not permitted.