RT-11 and TCP/IP

Jerome Fine replies: Any RQDX1,2,3 controller can support the RX50 dual drive in the backplane since it has no bus grant continuation. ONLY the RQDX3 supports the RX33. In a BA23, the use of just the RX50 is via the right hand header in the I/O distribution panel which is just in back of the space for drives. A straight through cable without any twists is the correct connection. Likewise for the cable from the RQDX3 to the I/O distribution panel via the little opening just below for I/O distribution panel. Yes!!! I AGREE!! RD53s drives don't live all that long. and SCSI is still very expensive since the Qbus host adapters have not become inexpensive, as has most other PDP-11 hardware. Why don't you just switch to an emulator on your PC? It is also much faster than the PDP-11!!!! UNLESS the real fun is running on real PDP-11 hardware and the software is not the issue. With me, the software is far more important than the hardware. I have seen an 11/73 systems with a Sigma RQD11-EC, a quad ESDI MSCP compatible Qbus controller which allows up to 4 ESDI drives of any size. The system I saw had 3 * 600 Mbyte Hitachi DK515-78 drives. I was told that the drives set as units 1 and 2 were only for backup and all 20 partitions on each drive were identical after the backups had been done. Of the 60 partitions in total, all could be active simultaneously and all were bootable. The Sigma controller does allow fixed hard drives to be split into segments or partitions of various sizes each with its own UNIT number which can then be booted from a hardware level. But I understand that the drives were not segmented in any way as the firmware on the Sigma controller was told that the drives were removable. In fact, a demonstration was made - VERY CAREFULLY - and one of the drives was powered off, uncabled, and a different physical drive substituted while everything else was still running. The new drive cam back on line and was available without a hitch. You can do the same thing with an RD53, but you MUST usually UNLOAD and LOAD the device driver the activate an RD5x drive after it is powered down. If the system device is also the same device driver, then a software BOOT is required. If you are running with re-initialize the RQDXn and bring the RD5x back on-line. Sincerely yours, Jerome Fine RT-11/TSX-PLUS User/Addict