There was a period during which virtual storage immediately above the bar was not allocated. The rationale for not doing so was that incorrect AMODE(31) address arithmetic could yield values in that range.
I have no personal experience of the usefulness of this convention, but several contributors here whose judgment I trust noted that they had found it helpful. In any case this issue has now been parameterized. It also perhaps bears repeating that we are dealing here with AMODE(64) virtual storage, of which, for now at least, we have what may properly be called a plethora. John Gilmore, Ashland, MA 01721 - USA ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
