On Monday, 02/02/2015 at 05:55 EST, Rick Troth <[email protected]> wrote: > Evidently, FORMAT makes a note of the number of cylinders it block > formatted (the "low level" phase) first time around. Guessing that is > the purpose of ADTMCYL. I should have known. Sorry, Joe. > > So you can (RECOMP smaller and you can (RECOMP larger, but no larger > than some pre-detected size.
You can't RECOMP anything larger than the originally formatted size. You can RECOMP lower and back again, but no larger. And, yes, ADTMCYL holds the number of formatted cylinders.. The protection is in place because of the allocation map. Unlike other files on the disk, it is in a fixed location since it is written during FORMAT and its size never changes, as that size is based on the size of the disk. But if you add more cylinders, you add more blocks. And as you do that, the allocation map has to grow. But it can't grow. It's surrounded by other data. I have to say, it's kind of fun to lean back in my rocking chair and see my programmer id in FORMAT (DMSFOR) from back in the mid-80s. :-) Alan Altmark Senior Managing z/VM and Linux Consultant Lab Services System z Delivery Practice IBM Systems & Technology Group ibm.com/systems/services/labservices office: 607.429.3323 mobile; 607.321.7556 [email protected] IBM Endicott ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/
