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PDF File Transfers in Complex Distributed Environments
As a child, my friends and I played Telephone and marveled at how badly we mangled the stories we passed around. I never realized back then that playing Telephone might be laying a foundation for troubleshooting problems in later life.
At one time, transferring and displaying PDF reports created on the mainframe was a relatively simple process. Because these files are generated in EBCDIC format for viewing on the mainframe, one had simply to create the file with HOLD FORMAT PDF, transfer it to a PC with Windows or DOS TCP/IP FTP using the ASCII transfer option, and display it with Acrobat Reader.
As demand for these files broadened, however, from single users on locally connected networks (intranets) to multiple users in distributed environments (intranets and the Internet), so did the complexity of the transfer process.
Let’s look at one way that PDF files are distributed today through a network.
A Typical PDF File-Transfer Scenario
Upon creation, a file is transferred to a PC via FTP using the ASCII format transfer option. It is then attached to an e-mail and sent on its way to a final destination. As it travels, each server it encounters in the network evaluates it. As the number of servers (or "hops") increases, so does the number of evaluations. In some instances, these evaluations change files, making them appear corrupted and rendering them unreadable as PDF files by Acrobat Reader.
Is there a way to prevent this corruption? The answer is, it depends on how much of the network you or your company controls.
How to Improve the Success of PDF File-Transfers Within Your Intranet
When transferring files within your intranet, we recommend ensuring that each of your servers uses the same National Language Translation Code Page. We also recommend that you configure your servers to allow the largest possible logical record length (LRECL) for these files. Failure to do so could result in truncation of lines within these files, causing them to be corrupted.
What About PDF Transfers Via the Internet?
Please note that it is our policy to support and certify only FTP transfers of PDF files. While we are happy to offer advice concerning other techniques, because of the considerable potential for corruption using other transfer methods we cannot guarantee their outcomes.
When you send PDF files as e-mail attachments across the Internet they are fair game for corruption at every "hop" or application between you and your recipients. While you cannot prevent this, there is a workaround you can use to improve your chances of success. Normally, PDF files are transferred using a MIME type of APPLICATION PDF. By changing the MIME type to APPLICATION PLAIN TEXT, however, you can prevent these intermediate evaluations from occurring, thus ensuring that Acrobat Reader will be able to open your files. Additionally, transferring PDF files in Plain Text format allows Acrobat Reader to open them without prejudging the contents. After bypassing its PDF-format-checking process, Acrobat Reader will open the file and will format and display it properly.
In summary, if you want to make sure PDF files arrive at their destinations in the form intended (and are not mangled as in Telephone) you know several steps you can take to make servers along the route behave.
Your Feedback Is Requested Concerning a Proposed Change
We are considering changing the format of PDF files created on the mainframe (MVS and VM) from EBCDIC to ASCII. The purpose would be to create files that did not require translation into ASCII as part of the file transfer process. Doing so, however, would render the files unreadable on the mainframe.
Please let us know what you think. Your feedback is very important to us. Please send responses (or questions) to Focusreleasemanager@informationbuilders.com.
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