The limit for CKD volumes is a little more than 54GB. I come up with a number closer to 500GB. Past that and IBM will need to go to logical volumes on a physical volume. The reason is the CCHHR count field.
Max CC is FFFF, which give 65536 cylinders (don't forget cylinder 0) Max HH is E, which gives 15 tracks per cylinder That gives: 65536 cylinders times 15 tracks times 56664 bytes = 983040 tracks * 56664 983040 tracks * 56664 = 557,053,378,560 My question is who is going to want that much data on a single volume? In 10 years someone may want that much. I'll be glad to not have to wait for that volume restore as I hope to be long retired. Christopher Y. Blaicher BMC Software, Inc. Austin Development Labs (512) 340-6154 The comments made are my personal opinions. BMC Software, Inc. makes no representations or promises regarding the reliability, completeness, or accuracy of the information provided in this discussion; all readers agree not to rely on this information or take any action against BMC Software in response to this information. -----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Edward Jaffe Sent: Friday, March 02, 2007 4:13 PM To: IBM-MAIN@BAMA.UA.EDU Subject: Re: FBA rant was Re: IBM S/360 series operating systems history I agree with you Clark re: the short-sightedness of not supporting FBA in MVS. Because of that dumb decision, z/OS is the only mainframe operating system left in the 21st century that can't handle SCSI. :-( That situation should be rectified! But, why do you say we need FBA in order to support volumes greater than 54GB? Why can't ECKD be extended to support larger volumes? -- ---------------------------------------------------------------------- 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
