Jerome Fine replies: Do you use RT-11 very much? Which monitor and what programs do you run? Also, how did you boot RT-11? Is it possible that the WRITE PROTECT button on the front panel is pressed? You can determine that by sending the command: DUMP/TERM DU0: If the DUMP works, then you are at least able to read the drive. In addition, also try the command: SHOW DEV:DU which will also show the map between the logical MSCP units and the physical hardware. Perhaps the ODS-2 mapping was different. I presume you are using an RQDX3 (M7555) and DS3 is used on the drive. Also, which monitor are you using? A DEC distributed monitor will not have any strange aspects, but a SYSGEN might. RT11SJ and RT11FB use DU.SYS while RT11XM uses DUX.SYS as the device driver. And check the cables on the drive a second time. Finally, does the RX50 work? If not, begin to suspect hardware problems? Sincerely yours, Jerome Fine

Jerome Fine replies: Interesting!!!!!!!!!! Now how did you acquire a bootable RX33 floppy? I presume from the same source as the RX50. Do you have the complete V5.04D distribution? And now that I am thinking of it, do you have both the RX50 and RX33 drives connected at the same time? By the way, RT-11 is able to do an actual FORMAT (real Low Level Format) on the RX33 drive with the RQDX3 controller. I think this was the first (and probably last) time that DEC supported an LLF for a floppy. Of course, it was not really of much help since the LLF for the RX33 media results in the same LLF as is used for the HD 5 1/4" PC floppy and of course the same capacity in terms of blocks. So at that point, with pre-formatted 5 1/4" media available for the PC world, DEC could not even pretend that media there were already sold with the LLF done were unique. And since the drive was one of the standard PC options which already have the ability to do a LLF on the PC, there was no excuse for not being able to do an LLF under RT-11 as well. Very confusing!!!!!!!!!!! While you did not show the output from the DUMP/TERM DU0:/ONLY:8. command, I will assume that it was reasonable and that you stopped it with a double CTRL/C command. I also showed the optional switch (/START:789. is allowed as well with a decimal point) which will DUMP only a single block. If you can READ the logical partition DU0:, then I am at a complete loss as to why you can't WRITE it. Does anyone know if the RD54 has a WRITE PROTECT jumper that can be placed on the drive? Of course, it might also be the cables or the drive that have a hardware problem, but that seems so unlikely. On the other hand maybe the WRITE PROTECT button on the front panel for the BA23 box is not lit and still pressed IN. I can't ever remember seeing that happen. And if I am ever able to READ a drive on RT-11, then baring my doing something explicit to prevent my attempting to WRITE on the drive that I know about since it would be something very explicit that would be required, I have never been unable to WRITE to a hard drive under RT-11 when a DUMP was already successful. Does anyone else here have a suggestion? Also, try just the command: INIT DU0: Maybe there is something funny with V5.04D of RT-11????? This looks completely correct and expected. It also says that you booted from the RX50 which I presume is DU1: At this point, don't try anything fancy until you can get DU0: to work. Then you can try some tricks on RT-11. I am at a complete loss as to why the DU0: is not able to have an INIT performed. One other test that might shed some light is: RUN SIPP and answer DU0:/A press <RETURN> twice to get to the data entry part of the program. Then type in any value that is different followed by <RETURN> and on the next line type <CTRL/Y> followed by <RETURN> If at this point you get an error message, then the drive is not accepting a WRITE operation. I still will not be able to explain, but it would be consistent. Another test will be the command (assuming the RX50 is DU1:): COPY/DEVICE DU1: DU0: If this also does not work, then again it is consistent. The result will be an exact copy of the 800 blocks from the RX50 onto DU0: of the RD54, but that can VERY easily be fixed up by the command: SQUEEZE DU0: either before or after you send the command: BOOT DU0: If any of these commands allow you to WRITE on the RD54, you may have found a bug in V5.04D of RT-11. NO!!!!!!!!!!!!!!!!! This post is not the place for a seminar on splitting up the RD54 disk into five logical partitions. Actually, that is already done by the RQDX3, you just need to set up the MAP correctly. Once you can BOOT DU0: that will be the time. The SET commands are trivial, but you have to decide which logical partitions are which. In V5.04D of RT-11, DEC omitted one instruction in the code for the secondary boot program and as a result, RT-11 can not use a non-zero physical partition as the system device. The extra instruction was added in a later version, but DU.MAC can easily be fixed as well. The command: INIT DU0:/SEGMENT:5 sets up the file structure for DU0: so that there are only 5 segments in the file directory instead of the maximum of 31. Each file directory segment is only two blocks (in RT-11 they always start at physical block 6) and each of the logical (or physical depending on how you view the mapping of the RD54) holds 65536 blocks with block 65535 (blocks are numbered from 0 to 65535 decimal) normally being inaccessible by convention. This means that you devote only 68 blocks at most for the initially empty file structure set-up out of 65535 blocks when there are 31 file directory segments. Since each file directory segment can hold a maximum if 72 file entries even after a SQUEEZE command is performed, having only 5 file directory segments (from block 6 to 15) would normally limit you to a maximum of 358 files (the last segment can hold only 70 files due to a software limitation). In practice, the actual total for a novice would be only about half that number or even less. THEREFORE, NOT RECOMMENDED for a partition with 65536 blocks. If you are able to get the RD54 to work, please let us know. If not, answers to what happens when you try the commands: DUMP/TERM DU0:/START:8./END:9. RUN SIPP COPY/DEVICE DU1: DU0: would be very helpful. If you can get the RD54 to work, then comes the lesson on setting up the MAP tables via SET commands so that you can access the other physical (logical?) partitions. Good luck! Sincerely yours, Jerome Fine

Eric Dittman wrote: Found this in an addendum i had stashed away: /Jumper W23 on the RQDX3 must be on pins 1 and 2 when used with rd54s. If not disk corruption can result/ -nick