In a message dated 10/27/2006 9:07:17 A.M. Central Daylight Time, [EMAIL PROTECTED] writes:
>The only issue here is whether or not the device is offline. If there is an >F it is offline. Correct. The DISPLAY command was written decades ago when drives could really be not ready, is attempting to display as much info as possible, and uses the F as an abbreviation to allow room for more info, such as NRD. IBM apparently did not want to rewrite that part of the code just because it was no longer possible for DASD drives to become not ready. There is a large number of different reasons why IOS will not issue a Start Subchannel instruction to a DASD, and not ready was one of them long ago and in a galaxy far away. There is still a bit in the UCB for this condition. It does not occur on DASD anymore, but can occur on other device types (tape drives, e.g., on which you can still mount a new volume). >I believe the NRD is a throw back to the old days when you >could flip a switch that would READY or NOT READY the physical drive. Correct. There are probably still some DASD error recovery situations in which IOS uses this bit as a quick and dirty way to render a device unstartable. There is also a bit in the IOSB that a caller of STARTIO can turn on to tell IOS to do the SSCH even if the UCB says the device is not ready. >If I am wrong, please feel free to correct - especially you dinos out there. You are not wrong. Bill "pre-Cambrian" Fairchild "Facts are the enemy of truth." [Don Quixote in Man of La Mancha] ---------------------------------------------------------------------- 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
