The SAM access method is designed for the sequential processing of records. It should always be selected if files are not to be shareable and random access is not necessary. This record structure is simple and yet flexible and allows both fixed- and variable-length records. Depending on the application, both types of record length can help to save memory capacity.
The fact that keyed access is not used means that path lengths are considerably shorter than is the case with ISAM. If required, it is a simple operation to convert the file into a file with a key (e.g. using an editor).
The advantages of SAM are:
reading and writing are performed record by record
limited updating facilities and high performance (PUTX)
short program runtimes achieved by reading the next block in advance
files can also be processed using PAM
high performance achieved by eliminating shareability during updating