On Thu, 14 Sep 2006 22:21:22 -0500, Tom Schmidt misspoke: >On Thu, 14 Sep 2006 18:29:19 -0400, Thompson, Steve (SCI TW) wrote: > >>-----Original Message----- >>From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On >>Behalf Of Tom Schmidt >>Sent: Thursday, September 14, 2006 5:22 PM >>To: [email protected] >>Subject: Re: IDCAMS and DF/SORT support for LBI >> >><snip> >>LBI is limited to tapes, not DASD. (Too bad - I would like to see the >>3390 geometry disposed of at long last. 3390's track length is getting >>cramped.) >><snip> >> >>The 3390 does not have a problem with LBI. IBM has a problem with DASD >>and LBI. Something about the architecture of a DCB... > >(Is it really the DCB that's the limit? I don't think so.) > >The tapes use DCBs (and only DCBs) and they managed to overcome the 32760 >byte limitation inherent in the original question here. 3390 uses either >DCBs or ACBs (a handy alternative, eh?) and the folks in San Jose have >worked some serious magic recently to mine unused and then underused bytes, >nybbles and bits out of the various I/O control blocks in order to provide >the somewhat recent support for million-plus track files on DASD. > >All I'm asking is: since a 3390-54 is still anchored on 3390 geometry, >isn't it time yet to expand that (virtual) track length to something >vaguely similar to the underlying shark disks? > >Or, better yet, bring out a new DASD architecture. Maybe FBA or maybe (by >now) something better.
The "(and only DCBs)" is an overstatement, I think. DCBs and DCBEs might be closer to reality. (And now, back to your regularly scheduled comedians...) -- Tom Schmidt Madison, WI ---------------------------------------------------------------------- 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
