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Imaging Cromemco 5.25" floppy disks

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    Imaging Cromemco 5.25" floppy disks

    Hi,

    I am in the process of trying to image some old mid-80s Cromemco CDOS and Cromix floppies for my father. Back in the late 80s we used a program called Xenodisk to copy disks on an XT class PC. Unfortunately whilst I still have the PC the floppy with Xenodisk on has worn to the point it is transparent. I have some experience in using Dave Dunfield's ImageDisk software to image MSDOS format floppies but it doesn't like the Cromemco disks out of the box.

    Does anyone know of an effective way to image these old disks using ImageDisk?

    For reasons that have been lost to time some (not all) of the disks have a write protect sticker over the index sector hole. Anyone remember what that was for?

    thanks,

    Dave

    #2
    My recollection is that CDOS floppies use a single-density (FM) boot track; the rest of the disk is pretty much plain MFM.

    So, you'll need a floppy controller that's FM-capable. There's a program on the same page as Imagedisk called TESTFDC (or something like that) that will assess the capabilities of your system.

    Are you sure that the program wasn't Xenocopy? That'd be Fred Csin--he still hangs out on the cctalk list. Maybe he has a disk that he can send you.
    Reach me: vcfblackhole _at_ protonmail dot com.

    Comment


      #3
      You are right it was Xenocopy not Xenodisk. I shouldn't have trusted the dodgy handwritten floppy label (and my 35 year old memory).

      The floppy controller should be OK given that it worked with Xenocopy but I'll give it a go.

      An alternative would be to use a flux imager like fluxengine (which I have). It should be able to make sense of the format. Will report back what was required as info on what to do for 5.25" Cromemco disks seems scarce.

      Comment


        #4
        I looked at the CDOS-02_58.IMD file, and Track 0 is 18 sectors of 128 bytes (18 * 12 = 2304 = 0x0900 bytes.
        The remaining tracks are 10 Sectors of 512 bytes (10 * 512) = 5120 = 0x1400 bytes
        Total = 406784 which matches the .img file.

        I'm 99% sure the GreaseWeazle can Image (read & write) these files, but I haven't had time to try it yet.


        Larry

        Comment


          #5
          I've updated my GreaseWeazle to v0.15, and now it will read and write the Cromeco CDOS-02_58.IMD file
          after converting it to a .SCP type file.

          Larry

          Comment


            #6
            As noted, with the right hardware and software CDOS diskettes can be read and written fairly easily.

            But do you just want to image/copy these diskettes or actually read the files on them? That would be a different story, especially the Cromix diskettes. I assume that the original Cromemco system is no longer available?

            The taped-over index holes are a mystery; are you sure that these diskettes have not been reused for something like a C64 that does not use index holes (although there'd still be no need to cover them up...)?

            Comment


              #7
              Taping over index holes was a dodge that sometimes worked when trying to read disks that leave out the IAM and its preamble on PCs.

              The standard PC FDC is "blind" for a certain period after the index hole and thus can miss the IDAM on the first sector on the track.

              So long as you use software that doesn't wait for an index before starting reading, this works. I preferred hooking a T flipflop in series with the index line, which still allowed almost all reading software to work.
              Reach me: vcfblackhole _at_ protonmail dot com.

              Comment


                #8
                Originally posted by Chuck(G) View Post
                Taping over index holes was a dodge that sometimes worked when trying to read disks that leave out the IAM and its preamble on PCs.

                The standard PC FDC is "blind" for a certain period after the index hole and thus can miss the IDAM on the first sector on the track.

                So long as you use software that doesn't wait for an index before starting reading, this works. I preferred hooking a T flipflop in series with the index line, which still allowed almost all reading software to work.
                Interesting, thanks; learn something every day. But what does the FF do for you? Stretch the pulse? Change timing to front edge of hole instead of back? Or?

                Comment


                  #9
                  Simply asserts INDEX/ every other rotation. Still allows for valid returns for "Sector not found" etc. instead of just hanging (with taped-over hole).
                  Reach me: vcfblackhole _at_ protonmail dot com.

                  Comment


                    #10
                    Originally posted by Chuck(G) View Post
                    Simply asserts INDEX/ every other rotation. Still allows for valid returns for "Sector not found" etc. instead of just hanging (with taped-over hole).
                    Clever!

                    Comment


                      #11
                      The file listings I have for those 4 images are:

                      Code:
                      $ cpmls -f com8x -D CCPM86-1.RAW
                           Name    Bytes   Recs  Attr     update             create
                      ------------ ------ ------ ---- -----------------  -----------------
                      CCPM40FH.SYS    32K    256    
                      CCPM40HD.SYS   102K    804    
                      CCPMHRD2.SYS    96K    768    
                      MENUHELP.TXT     2K      9    
                      MENUREAD.ME      2K      4    
                      MENUTEMP.SUB     2K      1    
                      MFORM   .CMD     2K     14 R  
                      NOW     .COM     2K      2 R  
                      PIP     .CMD    10K     70 R  
                      PRINT   .CMD     8K     57 R  
                      REN     .CMD     4K     19 R  
                      SCOPY   .CMD     6K     40 R  
                      SDIR    .CMD    14K    100 R  
                      SET     .CMD     8K     56 R  
                      SETMDRV .CMD    16K    127 R  
                      SETMEM  .CMD     2K     13 R  
                      SHOW    .CMD     8K     53 R  
                      SUBMIT  .CMD     4K     28 R  
                      SW!     .CMD     4K     29 R  
                      SYSGEN  .CMD     4K     23 R  
                      SYSTAT  .CMD    20K    148 R  
                      TERM0   .HLP     2K      3    
                      TERM1   .HLP     2K     16    
                      TERM2   .HLP     4K     19    
                      TERM3   .HLP     4K     25    
                      TERM4   .HLP     2K     15    
                      TERMINIT.CMD    38K    297 R  
                      TYPE    .CMD     2K     15 R  
                         28 Files occupying    214K,     382K Free.
                      
                      
                      $ cpmls -f com8x -D CCPM86-2.RAW
                           Name    Bytes   Recs  Attr     update             create
                      ------------ ------ ------ ---- -----------------  -----------------
                      INITDIR .CMD    36K    285 R  
                      LSTED   .COM     2K     13 R  
                      MEDMAN  .IN      2K      5    
                      MEM     .CON     6K     48    
                      NEWMEDIA.CMD    10K     76 R  
                      NEXT    .COM     2K     16 R  
                      NOW     .COM     2K      2 R  
                      PASS    .CMD    30K    232 R  
                      PASS    .DOC    10K     69    
                      PCMODE  .SUB     2K      7    
                      PIN     .RSP     4K     26    
                      REN     .EXE     2K     16    
                      RTM     .CON     8K     59    
                      SAVE816 .CMD     2K      6 R  
                      SHELL   .NPC    10K     69    
                      SHELL   .PC     22K    174    
                      SPL     .CMD    22K    165 R  
                      SPLLOCAL.SUB     2K      1    
                      SPLMAP  .SUB     2K      1    
                      SPOOL   .CMD    34K    263 R  
                      SUP     .CON    10K     68    
                      SYSDAT  .CON     4K     26    
                      TIME    .EXE     2K     16    
                      TXTED   .COM     2K     16 R  
                      XIOS40FH.CON    16K    128    
                         25 Files occupying    244K,     352K Free.
                      
                      
                      $ cpmls -f comb -D CPM822K1.RAW
                           Name    Bytes   Recs  Attr     update             create
                      ------------ ------ ------ ---- -----------------  -----------------
                      ASM     .COM     8K     64    
                      BIOS1   .ASM     6K     37    
                      BIOS4   .ASM     6K     34    
                      BIOS8   .ASM     2K     13    
                      BIOS9   .ASM     2K     15    
                      CLOCK   .COM     2K      7    
                      CONVERT .COM     4K     18    
                      COPY    .COM     4K     17    
                      CRCKLIST.        4K     22    
                      DDT     .COM     6K     38    
                      DSK     .COM     2K      4    
                      DUMP    .ASM     6K     33    
                      DUMP    .COM     2K      4    
                      ED      .COM     8K     52    
                      FORMAT  .ASM    18K    130    
                      FORMAT  .COM     4K     18    
                      GBBIOS  .ASM    58K    455    
                      GBBOOT  .ASM     6K     45    
                      GBCBIOS .ASM     4K     19    
                      GBCBIOS2.ASM     8K     54    
                      GBCBIOS3.ASM     4K     31    
                      GBCBIOS5.ASM     6K     36    
                      GBCBIOS6.ASM    12K     86    
                      GBCBIOT3.ASM     6K     40    
                      GBCBIOU3.ASM     4K     19    
                      GBCBIOV3.ASM     4K     31    
                      GBCBOOT .ASM     6K     36    
                      GBCROM  .ASM     4K     32    
                      GBROM   .ASM     6K     42    
                      LOAD    .COM     2K     14    
                      MOVCPM  .COM    14K     98    
                      PIP     .COM     8K     58    
                      STAT    .COM     6K     41    
                      SUBMIT  .COM     2K     10    
                      SYSGEN  .COM     2K     11    
                      XSUB    .COM     2K      6    
                         36 Files occupying    248K,     248K Free.
                      
                      
                      $ cpmls -f comb -D CPM822K2.RAW
                           Name    Bytes   Recs  Attr     update             create
                      ------------ ------ ------ ---- -----------------  -----------------
                      ASM     .COM     8K     64    
                      BIOS1   .ASM     6K     37    
                      BIOS4   .ASM     6K     34    
                      BIOS8   .ASM     2K     13    
                      BIOS9   .ASM     2K     15    
                      CLOCK   .COM     2K      7    
                      CONVERT .COM     4K     18    
                      COPY    .COM     4K     17    
                      CRCKLIST.        4K     22    
                      DDT     .COM     6K     38    
                      DSK     .COM     2K      4    
                      DUMP    .ASM     6K     33    
                      DUMP    .COM     2K      4    
                      ED      .COM     8K     52    
                      FORMAT  .ASM    18K    130    
                      FORMAT  .COM     4K     18    
                      GBBIOS  .ASM    58K    455    
                      GBBOOT  .ASM     6K     45    
                      GBCBIOS .ASM     4K     19    
                      GBCBIOS2.ASM     8K     54    
                      GBCBIOS3.ASM     4K     31    
                      GBCBIOS5.ASM     6K     36    
                      GBCBIOS6.ASM    12K     86    
                      GBCBIOT3.ASM     6K     40    
                      GBCBIOU3.ASM     4K     19    
                      GBCBIOV3.ASM     4K     31    
                      GBCBOOT .ASM     6K     36    
                      GBCROM  .ASM     4K     32    
                      GBROM   .ASM     6K     42    
                      LOAD    .COM     2K     14    
                      MOVCPM  .COM    14K     98    
                      PIP     .COM     8K     58    
                      STAT    .COM     6K     41    
                      SUBMIT  .COM     2K     10    
                      SYSGEN  .COM     2K     11    
                      XSUB    .COM     2K      6    
                         36 Files occupying    248K,     248K Free.

                      Larry

                      Comment


                        #12
                        Managed to get the disks imaged with Imagedisk. Had to get IMD to use single-step, 1:1 interleave and it was fine. My controller isn't clever enough to understand the FM first track but appears to have read the rest of the data correctly. I've also taken a fluxengine image of the disk as well for good measure. I'll have a look at the GreaseWeazle software too. Too many imaging solutions.

                        I'm just looking to recover data from the disks. Sadly I missed the opportunity to save a Z-2 CS-250 system 20 or so years ago...

                        Comment


                          #13
                          Sorry, you lost me; which images are these?

                          Comment


                            #14
                            If you don't care about the boot track and just want the data, why not 22Disk or a similar package? Just read the files directly.
                            Reach me: vcfblackhole _at_ protonmail dot com.

                            Comment


                              #15
                              Originally posted by ldkraemer View Post
                              The file listings I have for those 4 images are:
                              ...
                              Larry
                              The file listings you provided for CCPM86-1 and CCPM86-2 are for CompuPro Concurrent CP/M-86.

                              The file listings you provided for "CPM822K1" and "CPM822K2" are for CompuPro CP/M-80 version 2.2K.

                              Not sure how this relates to Dave's original question regarding imaging of Cromemco CDOS and CROMIX floppy disks.
                              Last edited by hmb; May 8, 2020, 03:53 PM.

                              Comment

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