Jerome Fine replies: You are confusing the maximum number of RT-11 partitions that can be easily handled by RT-11 at the same time WITH the maximum number of partitions that RT-11 can see when the command: SET DUn: UNIT=0,PART=p is used. Prior to V5.03 of RT-11, partitions were NOT supported. For V5.03 of RT-11 up to V5.04G, "n" is from 0 => 7 for a total of EIGHT, but p has the range 0 <= p <= 255 for a total of 256 partitions. That means that an 8 GByte drive can be easily managed even though ONLY 256 MBytes can easily be seen at one time. The the command changes to: SET Dnn: UNIT=0,PART=p For V5.05 of RT-11 up to V5.07, "nn" is from 00 => 77 (OCTAL in essence although the actual usage of the device name is RAD50 of all three characters) for a maximum total of SIXTY-FOUR (note that a SYSGEN is required), but p still has the range 0 <= p <= 255 for the same total of 256 partitions. That means that an 8 GByte drive is still easily managed, but now 2 GBytes in 64 RT-11 partitions can easily be seen at one time. NOTE that "UNIT=0" is only in my examples and that any valid physical unit is allowed. Of course if your hard drives are 256 MBytes or less, then any distributed RT-11 monitor for V5.03 of RT-11 and later can look at the whole drive at the same time. However, I hear that Tim Shoppa has a 9 GByte drive that has all 256 RT-11 partitions. I also have a number of ST32550N drives as well with 31 RT-11 partitions. Under Ersatz-11 on a PC with a host adapter, I am able to interchange them at will with a real DEC PDP-11, although the host adapter I usually use is a CQD 220/TM. I presume that a real DEC RQZX1 is probably still more expensive - does anyone know? Those prices are unusual, but do occur if you watch for them. Often they are offered AS IS and you take your chances. When the board still works (which is usually most of the time as it happens), the buyer has struck gold. Sincerely yours, Jerome Fine -- 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.