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Looking for 8-bit MFM controller for a ST-4096 drive... suggestions?

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    Looking for 8-bit MFM controller for a ST-4096 drive... suggestions?

    As per the title...

    I have been looking and seem to keep finding,
    - 8 bit controllers w/o stated support for this drive
    - 16 bit controllers that do support it, but no clear evidence the controller will work in an XT class machine

    I’ll take any leads anyone has...

    #2
    I have these two:

    http://www.vcfed.org/forum/showthrea...ive-Controller

    http://www.vcfed.org/forum/showthrea...ive-Controller
    PM me if you're looking for 3½" or 5¼" floppy disks. EMail “ ” For everything else, Take Another Step

    Comment


      #3
      Thanks Stone, are those controllers definitively supporting the ST-4096? I’ve had trouble confirming with certainty.

      Does anyone know how to tell the difference between the ST11R and the ST11M? The latter might work however most options available online seem to be labeled with a BIOS chip with both models described.

      Comment


        #4
        the difference between the ST11R and the ST11M?
        MFM and RLL (30% better density but requires hi-quality disk drive)

        ST-4096 has 1024 tracks so virtually any controller with "user C/H/S" should work i.e. WD-XT-GEN2 or Longshine.

        Comment


          #5
          Often later model 8 bit cards (like the WD XT-GEN etc) will allow dynamic configuration during the low level formatting process - where you can enter in any C/H/S you desire.

          16bit MFM cards will not work in an 8 bit slot.
          Twitter / YouTube

          Comment


            #6
            As I recall, ST4096 has 9 heads. Some really old controllers (such as the WD XT-GEN and XT-GEN2) are limited to 8 heads. So you're looking for a controller that can do 16 heads instead of 8. A great resource for this information for WD controllers is http://www.minuszerodegrees.net/manu...al/wdcontr.txt

            The ST11M does appear to support 16 heads, and the setup text file from Seagate show parameters for the ST4096. See ftp://ftp.seagate.com/techsuppt/controllers/st11m-r.txt
            --
            Thus spake Tandy Xenix System III version 3.2: "Bughlt: Sckmud Shut her down Scotty, she's sucking mud again!"

            Comment


              #7
              You also can try the OMTI controllers, they can handle such drives, as they have their own interactive setup where you can input the drive geometry.
              <album>

              Comment


                #8
                Originally posted by alecv View Post
                the difference between the ST11R and the ST11M?
                MFM and RLL (30% better density but requires hi-quality disk drive)

                ST-4096 has 1024 tracks so virtually any controller with "user C/H/S" should work i.e. WD-XT-GEN2 or Longshine.
                I should restate my question more clearly: I understand the difference between MFM and RLL, and am trying to understand how to identify whether a card is the ST11R or ST11M. I searched through some pictures online and found a couple of examples that seem to screen print the model on the PCB against one edge so I might have answered my question. Unfortunately these boards carry a ROM chip labeled with both model numbers, and the ST11M seems to be less common and more expensive. If anyone has a lead on a reasonably priced one (e.g. not 2x what the drive would cost) I'd be interested.

                Thanks all for the guidance on 16-bit cards being a no-no, the importance of paying attention to # of heads, and the referral to OMTI controllers. I took a look and don't see any reasonably priced options offhand but it's something I can be on the lookout for now.

                Comment


                  #9
                  Weren't some of those ST11 controllers actually ST11R/M?
                  PM me if you're looking for 3½" or 5¼" floppy disks. EMail “ ” For everything else, Take Another Step

                  Comment


                    #10
                    Originally posted by Stone View Post
                    Weren't some of those ST11 controllers actually ST11R/M?
                    Meaning the controller supports both encoding schemes?

                    Comment


                      #11
                      Originally posted by Bmurching View Post
                      Meaning the controller supports both encoding schemes?
                      Yes...
                      PM me if you're looking for 3½" or 5¼" floppy disks. EMail “ ” For everything else, Take Another Step

                      Comment


                        #12
                        Most of MFM controllers have 10MHz of 20MHz quartz/oscillator while RLL controllers have 15MHz or 30MHz ones.

                        Comment


                          #13
                          Originally posted by alecv View Post
                          Most of MFM controllers have 10MHz of 20MHz quartz/oscillator while RLL controllers have 15MHz or 30MHz ones.
                          Is this to suggest that controllers can or cannot support both encoding schemes?

                          Comment


                            #14
                            No, cheap controllers did not support both encoding schemes. But there was a "translating" controllers which translated real RLL C/H/S
                            into "pseudo MFM" C/H/S with 17 sectors per track.

                            JFYI: Intersting reading
                            http://bitsavers.trailing-edge.com/c...nual_Jan86.pdf

                            Comment


                              #15
                              Progress! I received a WD1002A-WX1 controller. After some work, the controller seems to work with my existing ST-225 that was formatted with an Everex EV-391.. I can see the logical drive and read/write without issue. When I connect the ST-4096 the computer throws a 1701 error and Spinrite does not see the disk. The connectors look the same and I have connected the drive identically. I’ve been running through jumper options though the ASCII manual I found is not terribly clear on meaning & location.

                              I am noticing that when running Spinrite against the st225 as a sanity check of the controller, Spinrite goes into an endless loop during drive fingerprinting, specifically the “drive write caches” step. I suppose I cannot rule out a controller issue until I do a successful Spinrite run.

                              Comment

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