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  1. W

    RK05 disk emulator

    Back in the day, I wasn't aware of the ability of the RK11D/RK05 to use 1 of N select lines. The gear was a hand-me-down and I didn't have access to schematics, We only had a few drives. I remember putting a Diablo as Unit #1 (first line bit 0) and the RK05's on as Unit #2 or #4 as a work around.
  2. W

    QBus Bus Termination.

    References for the various backplanes can be found at: http://web.frainresearch.org:8080/projects/pdp-11/backplanes.php https://www.conservatique.com/qbus-chassis/sigma-information-systems-sa-ba11. https://gunkies.org/wiki/QBUS_backplanes A little homework should give you confidence to...
  3. W

    RK05 disk emulator

    You can mix them if you only have a limited number of devices on a DEC controller. The Diablo 31 disks decode the select lines as 1 of N, versus the RK05 drive which decodes the same lines as drive #. A Diablo can be unit #1, but never #0. Jerry
  4. W

    QBus Bus Termination.

    I strongly agree with 100% of this, with exception of the number of boards. In oemMicronotes #29 it states that a single backplane does not requite termination if there are <20 AC loads, with more capacity depending on the processor termination. You should be able to calculate the actual board...
  5. W

    Looks like we have a new PDP-11 fan

    Duncan, BC has an average and steady humidity north of 70% and around 60 inches of rain a year. Is there really that much indoor static under these conditions? Jerry
  6. W

    Mystery port on Tektronix 4125 workstation

    There are brief references to a DMA interface ( https://w140.com/tekwiki/wiki/4125) . That would be a high speed way (~1 MB/sec) way to exchange data between the two devices. The DEC machines probably used a DRV11-B/DR11-B (16 bit parallel). No mention of the sofware needed on either side...
  7. W

    Reading an RQDX2 drive

    I'm going to venture that you have good copy of the drive imaged. Even though there are bad sectors, they were probably remapped by the controller. 200% guess work here. That one bad sector in the middle of the drive was remapped to the end area of the disk. if we can find it, a minor copy...
  8. W

    determining proper MAX/HEA values for BRU under RSX11

    I remember a few pathologic cases where we could not extend INDEXF.SYS in OD2(?) Volumes. I think we ran out of space for a large contiguous expansion of INDEXF.SYS, so it added a bunch of very small ones. This exhausted the the limit on extensions and limited the number of headers to well...
  9. W

    DLV11-J (M8043) clone?

    Of all the variants of DLV11-J, the layout and labeling of this device is pretty clear. Using IC type sockets however would seem to be a challenge. Looks like Mouser has the shorting links at *cough* $0.20 each. If you've sorted the addressing or serial options, why don't you post that bit...
  10. W

    PDP-12 at the RICM

    It could be a bad capacitor, especially if the machine has been idle for a while. Low electrolyte allows the plates depolarize. Applying power will reverse the process temporarily and after a while they get close enough to the specifications to function. My 861 power controller, with just 1...
  11. W

    "Directory input error" on a RL02k under RT11, is that cartridge now scrap?

    Commands you may want to consder DIR/BAD to scan for bad blocks COPY/IMAGE/IGNORE (RT-11 V4?) FORMAT/VERIFY/PATTERN (destructive)
  12. W

    Adding a DLV11J to an 11/73

    If I understand it correctly and presuming that your 11/73 is running, then it has some device that is already has a console at 177560. Depending on the device there may be one or more serial ports presenting. The DLV11J (or some variant) has been around for a long time. Each of the 4 serial...
  13. W

    Corvus disk drive for LSI-11

    I figured that the appearance on Bitsavers was not a coincidence.. ;) The status actually reports information about the handler that is loaded and what features/fuctions are available to programs. The details how to decode in AA-PE7VA-TC_RT-11_Device_Handlers_Manual_Aug91.pdf. There is also...
  14. W

    Corvus disk drive for LSI-11

    I have only seen these in the wild a few times and they were not under my administration. I would suggest you try the following to see if it possible to tease out some information that would you narrow down the a path to take. You may have already done many of these things. If you would...
  15. W

    DEC units on ebay

    18 bit addressing, 16 bit memory, 3 different processor modes… PDP11
  16. W

    Booting from units other than 0 on Emulex UCxx devices

    The boot code generally looks okay. I use UC07 which uses the same ROM. I speculate that this code sets up the registers in the UC07/17/18 directly. I have not dug into the details of the ROM Don supplied, but I think it reads first block of the boot scsi device directly (not using the...
  17. W

    Booting from units other than 0 on Emulex UCxx devices

    Are you able to provide an octal dump of first block (block 0) of DU2: ?
  18. W

    Booting from units other than 0 on Emulex UCxx devices

    Try changing R0 to the unit number you want.
  19. W

    RT-11 question: using multiple RAxx drives.

    The device configuration of MSCP type drives can be customized in RT11. The configuration is kept in boot drive and the mapping of controllers, drives and controlled by the DU handler. Start with AA-PDU0A-TC_RT-11_Commands_Manual_Aug91.pdf and SET DU command. You can map up to 8 devices in...