HP OpenVMS Systems

Physical device names and logical names?

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The Question is:

 
I have an AlphaStation200 4/166 running SRM V6.6-1. I have a program written
 for other Alpha's that assumes the CD ROM drive is DKA400 but this
 Alphastation shows the CD ROM as DKA500. Is there a way to reassign the
 device's system designation to DKA400?
 
 
 

The Answer is :

  Yes, use a logical name to refer to the device, rather than a physical
  device name. Change your program so that the device name is (say) "CD_DRIVE"
  rather than "DKA400". Prior to running your program, define the logical
  name, to specify which physical device should be used. For example:
 
	$ DEFINE CD_DRIVE DKA400:
	$ RUN PROGRAM
 
  on the other system with a SCSI CD drive at unit 500:
 
	$ DEFINE CD_DRIVE DKA500:
	$ RUN PROGRAM
 
  or, on a system with an IDE drive:
 
	$ DEFINE CD_DRIVE DQA0:
	$ RUN PROGRAM
 
  If you wish, you could write code that checks for the presence of the
  logical name (use SYS$TRNLNM) and substitute a default if undefined,
  or print a message asking the user to define it and rerun the program.
 
  When writing code for OpenVMS, you should always use a logical name when
  refering to devices, rather than the physical name as it allows you to
  reuse the code in different environments without changes.
 
  In your specific case, if the EXACT text of the name you used is "DKA400"
  you may be able to get away with
 
	$ DEFINE DKA400 DKA500:
	$ RUN PROGRAM
 
  but beware, that may cause trouble with programs that need to access a
  real DKA400 device in the new environment.

  

     

     
answer written or last revised on ( 19-JUN-2000 )
     
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