You can transmit any sequential data set using dynamic allocation; however, it is sometimes advisable to use staging data sets at the transmitting or receiving end of a transmission, or possibly both.
At the transmitting host, a staging data set describes a data set into which data is copied, or staged, in preparation for transmission. The priming of the staging data set can be performed by using a system utility or an application program. If a staging data set is used at the receiving end, it implies that the data must be copied out, again using a utility or application program, prior to that staging data set being used again for receipt of a subsequent transmission.
Various mechanisms and utilities are provided to aid in the use of staging mode transmissions.
Often the need arises for a discrete area or project group to transmit their own data sets. Rather than let each individual access all facilities, you can allocate to a project group one or more data sets into which data to be transmitted can be copied. The actual transmission can be performed by a person outside of the group (for example, a central operator) on request.
After the data set is transmitted to the remote location, the data can be copied into the relevant target data set.
There are various ways in which a staging data set can be shared by a number of users. Each user can write their own data into the data sets using DISP=MOD so that it is appended to the end of the file. Alternatively, a scheme can be set up where you can enter data into the staging data set only if it is empty.
CA SOLVE:FTS can empty a data set on successful transmission, and a utility is provided to ensure that a data set is empty before copying into it, thus facilitating the implementation of such techniques.
When you use staging mode, you must set up safeguards to prevent inadvertent overwriting of an input staging data set before successful transmission of a previous one, and to prevent receiving a transmission into a staging data set that has not been emptied from a previous transmission. Specific options on the definition of transmissions are provided to assist in safeguarding staging data sets.
When defining the From data set details, you can empty that data set when it has successfully transmitted. This, together with the restriction that data must not be copied into it unless it is empty, prevents the inadvertent overwriting of a data set before it is transmitted. A utility is provided to check that a data set is empty.
When defining the To data set details, you can set it so that the transmission cannot proceed unless the output data set is empty. This, together with a procedure that empties an output staging data set after the data in it has successfully copied out, prevents the inadvertent overwriting of an output data set. A utility is also provided that empties a data set.