Hal, you're absolutely correct in what you say. It's quite easy to convert JCL that reads tapes to reading files off of DASD. But for testing and developing things that actually read from tapes it is better if nothing changes. And I like the way Flex and Hercules does it.
Of course I've given up on this idea because I'm not ready for something this difficult (yet). And other companies already have such products. I'll have to wait and dream up another idea. -----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Hal Merritt Sent: 9. heinäkuuta 2008 18:06 To: [email protected] Subject: Re: STARTIO macro doc Still a little confused. What are you trying to do? If all you want to do is read a file, then just do it. Under z/os, the device type is of no particular interest to the application program. Z/os tracks the device type for you and uses appropriate I/O routines automatically. That is, a given file can exist on any flavor of tape, virtual tape, DASD, or whatever. The application program need only specify the file (dataset) name in the JCL or in the dynamic allocation interface. Assuming the file layout is the same, then the application program can read from all of those devices and remain completely unaware and uncaring. If you want to create a file, then just specify the device type you want to use for this specific instance in your JCL. Again, z/os handles all the details for you. Consider that 'tape' actually covers a very large number of possible device types, each with peculiar requirements. Some 'tape' units may actually be DASD under the covers. But, again, typically this is of no concern. HTH ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
