> For the complete documentation index, see [llms.txt](https://docs.editran.onesait.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.editran.onesait.com/documentacion-editran/ibm-editran-v5.3-cics-en/definition-and-management-of-buffer-files/introduction.md). # Introduction The editran buffer is the intermediate file where editran/G stores the data so that it can be sent by editran/P in transmission, and where editran/P stores the data on reception so that editran/G can obtain the various application files sent by the remote end. In the CICS environment, these are VSAM KSDS files. Their key is made up of the transmission session code associated with the data (24 characters) and the sequential order number (12 digits), which indicates the record number within the transmission session. For each transmission session there are two types of records: * The control record, with zeros in the order number, and it contains the control fields necessary for the transmission (number of records to send or receive, number of records sent or received, transmission dates and times, etc.). * The data records, with the ascending order number from 1 to n, where n is the number of data records associated with the transmission session. For the same session, the send and receive buffers must be different since the session code is the same for sending and receiving and there would be no way to distinguish the send data from the receive data. The record length depends on the transmission length. A buffer record length shorter than the transmission length cannot be used, but buffers whose physical records are longer than the transmission length can be used. There are different types of buffers that facilitate various ways of managing them depending on the user's needs; in the following sections each of them is specified, as well as the way to define and manage them. Except for specific buffers that are delete-defined in each transmission, for the rest of the buffers it is the user's responsibility to maintain these files. Since they are not delete-defined more than once, they undergo continuous record writes and deletions, so they gradually become "degraded." It is therefore highly recommended to perform a reorga from time to time, or a repro-delete-define-repro of them, to avoid the degradation mentioned. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.editran.onesait.com/documentacion-editran/ibm-editran-v5.3-cics-en/definition-and-management-of-buffer-files/introduction.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.