> -----Original Message----- > From: IBM Mainframe Discussion List > [mailto:[EMAIL PROTECTED] On Behalf Of Bill Fairchild > Sent: Tuesday, July 19, 2005 10:40 AM > To: [email protected] > Subject: Re: capacity of largest drive > > > <snip> > > The DCE (UCB DASD Class Extension) has two different halfword fields > indicating capacity. It would appear that the next model > larger in capacity than > the model 54 with 65520 cylinders will push the envelope off > its edge. One > reason why the capacity keeps going up is so IBM can postpone > giving us more > than 65536 devices on one LPAR. Something's gotta give > pretty soon. Or maybe > the DCE can be expanded by adding a prefix. :-) > <snide comment> Notice how it seems to be the hardware designers that are forced to "fix" or work around limits in z/OS? Some limits I can understand due to backward compatability. But I don't know why the 3390 geometry is so "sacrosanct". A DASD address in the CCW is CCHH. Why do we seem to be stuck with an HH of 00..0F? We are wasting a nybble of addressing. After all, the 3350 and 3380 geometry was not "set in stone" back in MVS days. Of course, I am arguing from ignorance. I don't know what the code looks like. </snide comment>
<snip> > > Bill Fairchild > > ---------------------------------------------------------------------- > 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 > ---------------------------------------------------------------------- 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
