When accessing an existing SAM file, any printer control character specification in the catalog is ignored. Moreover, in the case of SAM files with variable record length, the explicit specification of a record length in the catalog is ignored.
When EDT writes to a new SAM file, this file is usually stored on disk with the following default attributes:
variable record length without record length specification,
block size 2 for files on NK4 disks or block size 1 otherwise. If when the file is opened, the longest record that is to be written to it does not fit in this block size then a larger block size (maximum 16) is used.
If the attributes of new files shall differ from these default values then the file attributes and a file link name must be stored in the Task File Table before the file is written and the write operation must be performed using this file link name.
However, only the attributes described in section “File link names” are evaluated.
Usually, the files that are to be processed by EDT are read (fully or partially) into work files. It is not possible to process SAM files directly on disk (real processing). However, EDT is able to copy SAM files to ISAM files and then open these for real processing (see the @OPEN statement, format 2, "@OPEN (format 2) - Real processing of an ISAM file ").
File names used in EDT statements must comply with the requirements of the BS2000 data management system. EDT checks the validity of file names.
EDT is able to process records of length 0.
SAM files on magnetic tape cannot be processed using the @OPEN (format 1) and @CLOSE statements. In this case, the other statements (@COPY, @WRITE) should be used. If a new SAM file is to be created on magnetic tape, its name and properties must first be declared using the BS2000 /CREATE-FILE command.
It is not possible to process SAM files with record format UNDEFINED in EDT.
Similarly, attempts to process SAM files with the character set UTF16 and a fixed, oddnumbered record length are rejected.