[This note has been sent to the following InterNet address(es): [log in to unmask] it has also been sent to the following JP Morgan address(es) : To : JOHN DUNLOP ] Jeff Quade ([log in to unmask]) wrote: : We're installing 5.0 of MPE/iX. In reviewing the "backdate" process, : it appears that if you want to back off of 5.0, you must reinstall : 4.0. Is there no simpler way, like renaming files and rebooting? Or : rebooting from a different LDEV? We are a bunch of IBM Mainframe support : personnel who've been given an HP 3000 to support and we don't have a : firm grasp on MPE yet. Any help will be GREATLY appreciated. #Steve Elmer Software Engineer - HP - CSY wrote : #There is no "simpler" way to backdate. The backdate instructions exist to #assist you in accomplishing a backdate should it become necessary. It is #not really a recommended operation. #The reason the backdate process is necessary is that the update from 4.0 #to 5.0 made some significant changes to your system. Simply purging a few #files will definitely _not_ allow you to run 4.0 again. If you attempt #this, you can expect to have serious problems on your "4.0" system and #may even end up requiring a reload. I endorse this. I built a 'dual-boot' system which had two sets of separate system volume set disks , either of which could _only_ be accessed at system boot time. The 5.0 install went fine , the user volume sets containing my data were brought on-line without any problems. I shutdown the system and booted from my 4.0 system volume set and the system failed as it tried to mount the user volume sets. This was because the 5.0 install/update had converted various control data structures (e.g. VSIT, TXM logs etc) to a format which is not backward compatible with 4.0 and it had not told me of this. My solution was to reboot the 4.0 disks with the private volumes (old MPE V terminology dies hard) switched off. When MPE/iX 4.0 came up I powered up the 'converted' PV's and scratched each volume! #If you think the backdate process is too onerous, you haven't had to do #a reload recently... This statement is being economical with the truth ; to go backwards from 5.0 to 4.0 you must re-install MPE and AL your data ( in my case 200Gb on the Dev system)!!! #Please, please follow the backdate process if you must backdate! You have been warned, Tony Rendell [log in to unmask]