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Thread: MFM emulator, zrqch0 and friends - some notes

  1. #1

    Default MFM emulator, zrqch0 and friends - some notes

    I have been running a couple of mfm emulator boards (http://www.pdp8online.com/mfm/) for a while now. Most things working very well. At present all on 11/73 and 11/83 with BSD2.11 as the OS - but I have plans to move to older kit once I get an understanding of the MFM and what it does.

    First: hats off to some very nice kit. If YOU do what it says on the tin, then IT does indeed do what IT says on the tin.

    After that I wandered off into a few areas that gave me trouble - with the old XXDP dec formatters.

    Others may have seen these problems from different angles and be able to help.

    For those who have not seen them and head in an "MFM emulator" direction it may save you time and frustration.

    Background
    11/73 with RL02s and an M7555 (RQDX3 controllers).

    I have no trouble using the emulator to "image" an existing disk and then use that on the 11/73. Works a dream. I have copied 4 old RD5x type disks onto the beagleboard - and backed them up to my linux system with no problems.

    Then I decided to make a "disk" from scratch - without reading in an existing drive,

    Ttry as I might I just could not get the dec formatter ZRQCH0 to format the "emulated disk".


    DR>STA

    CHANGE HW (L) ? Y

    # UNITS (D) ? 1

    UNIT 0
    Enter controller IP Address (O) 172150 ? 172154
    What unit do you want to format [0-255] (D) 0 ? 0
    Would you like to revector a single LBN only [Y/N] (L) N ? N
    Do you want to use the "AUTOFORMAT" Mode [Y/N] (L) Y ? N


    Would you like to use the RCT - Revector known bad blocks [Y/N] (L) N ?


    **** WARNING ****

    ALL DATA ON SELECTED DRIVE WILL BE DESTROYED

    Write protect all drives not being formatted.
    Please verify that the selected drive is ON LINE
    and NOT write protected.

    If formatting RX33 media, insert media to be
    formatted in the selected drive.

    Do you wish to continue [Y/N] (L) Y ? Y


    MSCP Controller Model: 19
    Microcode Version: 4


    Formatting of Diskette on Drive 0 Begun.

    ZRQC SYS FTL ERR 00007 ON UNIT 00 TST 001 SUB 000 PC: 105742
    Controller has reported a fatal error in the FORMAT program.
    Status: LBN format error (drive FORMAT command failed)

    Drive 0 was not formatted successfully.

    ZRQC EOP 1
    1 TOTAL ERRS



    (and a thousand other attempts with Y and no and and and)
    So errors - some versions of the formatter produced errors about no Unit Information Table.

    But other folk on the web had prompts about "make a new one".

    So I moved from my trusty XXDP2.5 back to XXDP2.2 - same issue
    I went to an XXDP1 disk - no ZRXC?? of ANY sort!

    damn it.

    rummaged and rurached on the web, dunted my heid off the desk a few times. Perhaps ZRQCH0 I was running was not the unique and only ZRQCH0.
    I KNOW that the 0 should be a release and 1 for a different release.

    Anyway I found a bunch of other rl02 images on the web, downloaded them and one by one dd'd them into an RL02.
    One of these downloads had an image that did more sensible things
    DR>START

    CHANGE HW (L) ? Y

    # UNITS (D) ? 1

    UNIT 0
    Enter controller IP Address (O) 172150 ? 172154
    What unit do you want to format [0-255] (D) 0 ?
    Would you like to revector a single LBN only [Y/N] (L) N ?
    Do you want to use the "AUTOFORMAT" Mode [Y/N] (L) Y ? N


    Would you like to use the RCT - Revector known bad blocks [Y/N] (L) N ?


    **** WARNING ****

    ALL DATA ON SELECTED DRIVE WILL BE DESTROYED

    Write protect all drives not being formatted.
    Please verify that the selected drive is ON LINE
    and NOT write protected.

    If formatting RX33 media, insert media to be
    formatted in the selected drive.

    Do you wish to continue [Y/N] (L) Y ? Y


    MSCP Controller Model: 19
    Microcode Version: 4

    Do you want to use manufacturing bad block information [Y/N] (A) N ? N

    Downline load UIT [Y/N] (A) Y ? Y


    UIT Drive Name
    __________________________________________________ _____
    0 RD51
    1 RD52 part # 30-21721-02 (1 light on front panel)
    2 RD52 part # 30-23227-02 (2 lights on front panel)
    3 RD53
    4 RD31
    5 RD54
    6 RD32
    7 RD33

    Enter Unit Identifier Table (UIT) [0-7] (D) ? 5

    Continue if bad block information is inaccessible [Y/N] (A) N ? Y

    Please type in the serial number [8-10 digits] (A) ? 2222211111


    Formatting of Drive 0 Begun.


    ------------ FORMAT PROGRESS REPORT -------------


    1 minute into format ---- Formatting tracks, LBN # 34613
    2 minutes into format ---- Formatting tracks, LBN # 68885
    3 minutes into format ---- Formatting tracks, LBN # 103242
    4 minutes into format ---- Formatting tracks, LBN # 137310
    5 minutes into format ---- Formatting tracks, LBN # 171650
    6 minutes into format ---- Formatting tracks, LBN # 206007
    7 minutes into format ---- Formatting tracks, LBN # 240075
    8 minutes into format ---- Formatting tracks, LBN # 274721
    9 minutes into format ---- Formatting tracks, LBN # 309061
    10 minutes into format ---- First check pass, writing LBN # 35428
    11 minutes into format ---- First check pass, writing LBN # 70618
    12 minutes into format ---- First check pass, writing LBN # 105808
    13 minutes into format ---- First check pass, writing LBN # 140998

    Success!

    The disk that did the trick for me had an md5sum of 0c5c788d406b3ee6e27c3ebbd13f206a for the 10meg uncompressed file
    and a unix sum of 23864 10240
    and a dir list of the form
    775 ZVTMA0.BIN 19-SEP-81 29 034517
    776 ZVTNA0.BIC 19-SEP-81 13 034554
    777 ZVTOA0.BIC 19-SEP-81 19 034571
    778 WUZ24 .CNF 1-JAN-70 2 034741
    779 WUZ24 .MAP 1-JAN-70 2 034743
    780 DECX23.BIC 2-JAN-70 66 034747
    781 DECX23.CNF 2-JAN-70 2 035051
    782 DECX23.MAP 2-JAN-70 9 035053
    783 FERRER.LIB 2-JAN-70 2 035064
    784 FERRER.BIN 2-JAN-70 73 035066
    785 GAMMA .CNF 2-JAN-70 2 035177
    786 GAMMA6.BIN 2-JAN-70 95 035201
    787 GAMMA6.CNF 2-JAN-70 2 035340
    788 GAMMA7.CNF 2-JAN-70 2 035342
    789 GAMMA7.BIN 2-JAN-70 95 035344
    790 ZRQCB2.BIC 10-MAR-86 28 035503
    791 ZRQCH0.BIC 23-AUG-88 73 035537

    I dont know where I downloaded the disk from - dulich - too late at night and two tired, and my notebook degenerated into doodles.

    Note the 2 files "at the end" of the DIR way out of date sequence.


    So,
    I can now create a RD disk with 2048 cylinders,16 heads and have a humungous 280Mb disk on the MFM controller.

    I hope this saves someone else the time it took me to rummage about.
    Soon I will be trying the DX2 controller and then back into the mists of time on older processors ....

  2. #2
    Join Date
    Dec 2010
    Location
    Seattle, WA
    Posts
    2,032

    Default

    Did you try with this version?

    http://www.bitsavers.org/bits/DEC/pd...xxdp25.rl02.gz

    .DIR ZRQC*.*

    ENTRY# FILNAM.EXT DATE LENGTH START VERSION

    636 ZRQCH0.BIN 1-MAR-89 72 035016


    I don't have one of the MFM emulators yet myself to test. I plan on getting at least one from the next batch that is available.

  3. #3

    Default

    I am really sorry I dont know ;-( Bad science, no notes in my log book
    I think I downloaded 2.2 and 2.5 from that site.
    I have

    The md5sums are
    0c5c788d406b3ee6e27c3ebbd13f206a xxdp+1.rl02
    fd79b7a8d7d0d752a8052463c3f399e8 xxdp22.rl02
    04845865c63bcc912d7dee922ce9ac59 xxdp25.rl02
    253216f8c81f125f1fd35e0ae6a30d88 xxdp+.rl02
    and
    23864 10240 xxdp+1.rl02
    59679 10240 xxdp22.rl02
    35180 10240 xxdp25.rl02
    31081 10240 xxdp+.rl02

    Just downloaded them, I get
    [root@jondev Downloads]# md5sum xxdp*.rl02
    fd79b7a8d7d0d752a8052463c3f399e8 xxdp22.rl02
    04845865c63bcc912d7dee922ce9ac59 xxdp25.rl02
    So if I dont have those ones I have something cloned from them or vv.

    The file I am calling xxdp+1.rl02 is the rl02 image that worked well for me.
    Up until now I have only ever formatted a "real" dec disk, so the UIT block(s) was not an issue and both 2.2 and 2.5 worked for me.

    I dont think ANY of the 2.5 images I have used worked on on an mfm emulated disk that was created without cloning a real mfm disk.
    The 4 above are the ones that currently exist on my rl02 packs.

    I can highly commend djg's board. Living in Scotland I could not get the "whole show" in a oner. I had to get a Beaglebone locally and set it up. I was not sure how messy that would be. It was not, the manual worked fine and the conjuction of boards worked fine.

    What really beats me is if that I import it directly from the States I am a terrorist looking for that encryption technology. If I buy it over the counter in Scotland using untraceable cash I am not a terrorist!
    Your laws are as daft as ours!

  4. #4

    Default

    I have tried one of these emulators, allthough not with a PDP. This is my experience:

    On my unit the low-level format was also a bit of a hassle. Not because the formatter, but because I had missunderstood the role of the Drive 2 ID jumper. Having it set without actually having the second drive headers connected to anything somehow caused a lot of fail. Usually "Drive not ready".

    But once I realized and fixed the problem, the emulated drive would successfully low-level format in a PC/AT. I then had to write to all sectors in the target machine, and after that it has worked flawlessly ever since. I'm very happy with this device!

    The reason I had to do the low-level format in an AT was because the target machine never had a low-level formatter. If you waned a HDD with this machine, the original disks came pre-formatted and pre-installed from the factory, and the designers assumed the consumer didn't need to perform any formatting at all. Of course I could have written a WD1010 low-level formatter myself, but using the PC/AT was a much easier solution.
    Last edited by per; November 8th, 2015 at 01:39 PM.
    Current systems owned by me:
    Vintage:IBM PC/XT submodel 087 ( 1983 ), [Kon]tiki-100 rev. C (1983), Compaq Portable I ( 1984 ), IBM PC/XT submodel 078 ( 1985 ), IBM PC/XT286 ( ~1986 ), 3x Nintendo Entertainement Systems ( 1987 ).
    Obsolete:Commodore A500 ( ~1990 ), IBM PS/2 model 70/386 type 8570-161 ( 1991 ), Atari Lynx II ( ~1992 ), Generic Intel 486SX PC ( ~1993 ), AT/T Globalyst Pentium w/FDIV bug MB ( 1994 ), Compaq 486DX4 laptop ( ~1995 ).

  5. #5

    Default

    "Your laws are as daft as ours!"

    Given that we are cousins separated by a common language this should not be surprising.

    As to whether or not our House of Representatives and Senate have a higher or lower percentage of looney tunes than your equivalent legislative bodies I have no comment. To quote one of our legislators, "furthermore I have no comment regarding why I have no comment."

    Or my personal favorite from Sen. Pryor: "You don't need to pass an IQ test to be in the Senate".

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