Hi, I feel like a fool ... I just can't get an RX01 drive configured and attached in SIMH. If I boot RT11 from a virtual RL02, and do .SH DEV, the DX driver is listed as "Not installed". On SY: is DX.SYS and DXX.SYS, and since RT11 answered to the command ".set rx0 locked" "?KMON-F-File not found SY:RXX.SYS", I copied DXX.SYS to RXX.SYS ... and reboot of course. When I enter ".set rx0 locked" the response is now "?KMON-F-Invalid set parameter". I break to SIMH and enter "att rx0 simrx01.dat" and the SIMH response is RX: creating new file RX: buffering file in memory When I continue, and enter .SH DEV, DX is "Not installed". The CSR for DX is in SIMH 177174, the default 177170 is assigned to DY. I know that both drivers normally have the same CSR, I don't see a problem here. So, how do I attached and access (!) a virtual RX01 floppy? Has anybody used RX01 in SIMH before? thanks, - Henk. This message and attachment(s) are intended solely for use by the addressee and may contain information that is privileged, confidential or otherwise exempt from disclosure under applicable law. If you are not the intended recipient or agent thereof responsible for delivering this message to the intended recipient, you are hereby notified that any dissemination, distribution or copying of this communication is strictly prohibited. If you have received this communication in error, please notify the sender immediately by telephone and with a 'reply' message. Thank you for your co-operation.