DUP Problem with RT-11

I have been attempting for some to to write ALL 65536 blocks anyone know of what is wrong with what I am doing? I am using V5.03 of RT-11 under the Supnik emulator and I do the command: COPY/DEVICE/NOQU DU0:/START:0./END:65535. DU1:/START:0. However, ONLY 65535 blocks are transferred. On the other hand, If I do the command: COPY/DEVICE/NOQU DU0:/START:65524./END:65535. DU1:/START:0. then TWO blocks are transferred (I put 2 non-zero blocks into DU1: first), so I know that that it is possible to read block 65535 from DU0:, but there seems no reason why block 65535 is not written to DU1: via the very first command - especially when there is not even a warning message. Please do not reply that an RT-11 partition is ONLY 65535 blocks and that the last legal block is 65534. I have already proven that I can read block 65535 from DU0: when I use DUP.SAV, thus so as long as block 65535 can be read, there is absolutely NO reason that DUP.SAV should not allow me to write the same block into DU1:, but DUP.SAV does not seem to be able to do that and moreover does not even provide a warning message that DUP.SAV will ignore block 65535 when I explicitly direct that block 65535 be written to DU1: In addition, just in case anyone feels that DUP.SAV really ought not to provide at least a warning message, then try the command: COPY/DEVICE/NOQU DU0:/START:1./END:65535. DU1:/START:1. which does provide the warning message that I suggest is essential so long as DUP.SAV prohibits the user from writing block 65535 onto DU1: after block 65535 has been read from DU0:, even though, in my opinion there is NOTHING wrong with the command and DUP.SAV should do what the user has specified. Can anyone help? Any suggestions other than going into the DUP.SAV program and fixing this bug? Sincerely yours, Jerome Fine -- To obtain the original e-mail address, please remove the ten characters which immediately follow the 'at'. If you attempted to send a reply and the original e-mail address has been discontinued due a high volume of junk e-mail, then the semi-permanent e-mail address can be obtained by replacing the four characters preceding the 'at' with the four digits of the current year.