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Application Programming Access to Hardware Device?

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The Question is:

Hello, What would be the easiest way to talk to a card reader on a VMS system
 and put the data into a MUMPS database layered on top of openVMS.
I saw your example of an IDE disk controller driver and could use that to write
 a C driver for the device but am stumped after that.  Also, would these
 devices be addressable over the DECNET cluster?
Thanks for any info.

The Answer is :

  You will want to use sys$qio or language-specific calls to read the data
  from the card reader, using an existing device driver.  Examples of $qio
  calls are in various manuals in the OpenVMS documentation set, including
  programming details specific to existing hardware device drivers provided
  in the OpenVMS I/O User's Reference Manual.  Put another way, you should
  be able to accomplish this task using only user-mode application code,
  and you probably won't require a device driver.
  IDE disk controller device drivers are completely unrelated to this.  An
  OpenVMS device driver is a kernel-mode application for direct kernel-mode
  communications with a hardware device, and there are already device drivers
  for serial communications assuming that is the card reader is connected.
  (You would only need a device driver if you had a custom controller, such
  as a PCI adapter for the card reader, and particularly a PCI adapter that
  is not already supported by OpenVMS.)
  There is no such thing as a "DECnet cluster".  Please review the section
  "OpenVMS Cluster (SCS) over DECnet?  Over IP?" in the OpenVMS FAQ for
  additional details and background.
  You can use DECnet FAL and RMS calls to read and write files remotely.
  The OpenVMS Wizard would encourage retaining Compaq or other vendor for
  OpenVMS consulting and programming services.  If you wish to pursue this
  yourself, you will want to familiarize yourself with the contents of the
  OpenVMS Programming Concepts Manual.

answer written or last revised on ( 17-OCT-2001 )

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