Hi, all. I finally discarded my RD54 haunted by frustrating retries and burnt my yen on an Emulex UC08 board. I installed it to my PDP-11/53 and attached an old DDS2 drive and a 230MB MO drive. Now 2.11BSD runs as smooth as silk. Next I tried to install Ultrix-3.1, but I entered an unexpected weirdness. After entering setup phase 1, the initial setup aborted saying that it failed to access files under /usr. Some lengthy investigation revealed that UC08's emulation confuses Ultrix. The MO drive pretends an RD54 and the installer is quite confident of it. Once the kernel is in service, it checks the controller board and identifies it as a KDA50, which is connected to RAxx drives. Now the kernel treat the MO disk as a RAxx. Since RD54 and RAxx have different partition layout, kernel failes to find /usr filesystem and the installation process fails. To avoid this gap, I put a 540MB drive (bigger than an RA81, which is about 469MB) and configured it to behave as an RA81. The installation process now goes. After carefully studying src/sys/conf/dksizes.c, I also used a 230MB MO disk as an undersized RA81 and it seems to work well. I also tried SIMH. This time an emulated RD54 worked well, but a tape drive suddenly stopped during installation. I traced TMSCP protocol log and found a bug in the tape driver of Ultrix standalone installer, which hitted hidden incompatibility of SIMH. Here is an ad hoc patch for SIMH: --- simh.orig/PDP11/pdp11_tq.c Mon May 19 20:24:04 2003 +++ simh/PDP11/pdp11_tq.c Thu Nov 20 18:32:43 2003 @@ -260,7 +260,7 @@ CMF_SEQ|CMF_RW|MD_CDL|MD_CSE|MD_REV| /* compare */ MD_SCH|MD_SEC|MD_SER, CMF_SEQ|CMF_RW|MD_CDL|MD_CSE|MD_REV|MD_CMP| /* read */ - MD_SCH|MD_SEC|MD_SER, + MD_SCH|MD_SEC|MD_SER|MD_RWD, CMF_SEQ|CMF_RW|CMF_WR|MD_CDL|MD_CSE|MD_IMM| /* write */ MD_CMP|MD_ERW|MD_SEC|MD_SER, 0, /* 35 */ But of course you want to fix Ultrix, don't you? Another patch is here, but it is untested: --- src/sys/sas/tk.c- Sun Jan 24 06:24:58 1988 +++ src/sys/sas/tk.c Fri Nov 21 22:14:15 2003 @@ -247,6 +247,7 @@ op = M_O_READ; else op = M_O_WRITE; + tk.tk_cmd[0].m_modifier = 0; if((mp = tkcmd(op)) == 0) { printf("\n%s magtape error: ", tk_dct); printf("endcode=%o flags=%o status=%o\n", @@ -324,6 +325,7 @@ sizeof(struct tmscp) - sizeof(struct tmscp_header); tk.tk_cmd[0].m_header.tk_vcid = 1; tk.tk_cmd[0].m_cntflgs = 0; + tk.tk_cmd[0].m_modifier = 0; /* need to set the density if TU81 */ if (tkcmd(M_O_STCON) == 0) { printf("\n%s STCON FAILED: can't init controller", tk_dct); Ultrix seems unnecessarily square and not an OS of my type, but a fairly good testbed for emulated software and hardware :-) Naoki Hamada nao(a)tom-yam.or.jp