The GENESELECT Procedure (Experimental)

specifies the location where a working copy of the data will be stored. The RAM location requests that the working copy be stored in memory if enough memory is available for it and still allows for minimal calculations in one pass of the data.

The DISK location requests that the working copy be stored in a disk utility file. Storing the copy on disk can free a considerable amount of memory for calculations, possibly speeding up the program.

The SOURCE location requests that the data be read multiple times instead of being copied to memory or a disk utility file. SOURCE is slower than DISK because the DISK copy is converted to encodings directly usable in the calculations. The SOURCE location is preferable only when the data do not fit in RAM or in a disk utility file.

specifies the maximum amount of memory to allocate for the computations and the working copy of the data if the data are stored in memory. The optional suffix, B, K, M, or G, specifies bytes, kilobytes, megabytes, or gigabytes, respectively. Without a suffix, specifies the number of bytes. M can be fractional.

The default value depends on the computer and can considerably prolong the execution time if SAS cannot distinguish physical memory from virtual memory.

The SAS MEMSIZE system option sets an upper limit to the number of bytes.