1. Forum
  2. Usenet
  3. COMP.OS.CPM

  • What would be Disk Parameter Block specs for 720K 3.5 " ???

    From retrogear@21:1/5 to All on Sun Nov 28 07:42:17 2021
    I've gotten Concurrent CP/M v3.1 bootable for an IBM compatible 3.5" 1.44MB
    HD and have several requests for the 720K 3.5". What would be the DPB for those? I think the one I've found so far is for the 720K 5.25" quad density using John Elliot's chart here https://www.seasip.info/Cpm/cpm86form.html
    Also what ID byte would it be ?

    Larry G

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From retrogear@21:1/5 to retrogear on Sun Nov 28 19:02:37 2021
    On Sunday, November 28, 2021 at 9:42:18 AM UTC-6, retrogear wrote:
    I've gotten Concurrent CP/M v3.1 bootable for an IBM compatible 3.5" 1.44MB HD and have several requests for the 720K 3.5". What would be the DPB for those? I think the one I've found so far is for the 720K 5.25" quad density using John Elliot's chart here https://www.seasip.info/Cpm/cpm86form.html
    Also what ID byte would it be ?

    Larry G

    Someone just shared a Personal CP/M-86 Teledisk image with me that is for a 720K 3.5". So it's the same format as 1.44MB HD except half the sectors/track.
    80 tracks 2 sides 9x512 sectors/track. I converted it with TD02IMD utility to view the sectors and found the ID byte of the first sector = 11h so it is the DPB
    in John Elliot's chart for 720K. I think I can make this work in my source code for Concurrent CP/M-86 3.1. I have new 800K 3.5" disks that I might be able to write it on. The 22DISK definition should
    be easy enough.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From ldkraemer@gmail.com@21:1/5 to All on Mon Nov 29 18:24:00 2021
    Larry,
    Is this about the same as you came up with?
    [code]
    BEGIN COMF Compupro - DSQD 96 tpi 3.5" - 512 x 9
    DENSITY MFM, HIGH
    CYLINDERS 80 SIDES 2 SECTORS 9,512
    SIDE1 0 1,3,5,2,4
    SIDE2 1 1,3,5,2,4
    ORDER SIDES
    BSH 4 BLM 15 EXM 0 DSM 162 DRM 255 AL0 0F0H AL1 0 OFS 2
    END
    [/code]

    I sent you an email.

    Larry K.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From retrogear@21:1/5 to All on Tue Nov 30 03:32:18 2021
    DSM would be 354 or 162H. I don't even know if the sector order is linear or skewed.
    I'm assuming linear. I don't have a formatter yet. I see in the PCPM image I have there is
    a DSKMAINT.CMD. I need to see what that does. Work is keeping me busy at the moment.

    Larry G

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From ldkraemer@gmail.com@21:1/5 to All on Tue Nov 30 17:04:21 2021
    libdsk's dskform can also format the Floppy.

    [code]$ man dskform[/code]
    [code]$ dskform --help[/code]
    [code]$ dskform -type floppy -format sie3 /dev/fd0[/code]

    Larry

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From ldkraemer@gmail.com@21:1/5 to All on Tue Nov 30 16:44:43 2021
    22DISK can format if you have the Definition defined for the Image. Imagedisk ver 1.18
    should also be able to format the floppy.

    The 635_PCPM.IMD (635_PCPM.RAW) should work well with these Definitions: [code]
    BEGIN SIE3 Siemens PG-635 - DSDD 3.5"
    DENSITY MFM, LOW
    CYLINDERS 80 SIDES 2 SECTORS 9,512
    SIDE1 0 1,2,3,4,5,6,7,8,9
    SIDE2 1 1,2,3,4,5,6,7,8,9
    ORDER SIDES
    BSH 4 BLM 15 EXM 0 DSM 350 DRM 255 AL0 0F0H AL1 0 OFS 4
    END

    # SIE3 Siemens PG-635 - DSDD 3.5" - 512 x 9
    diskdef sie3
    seclen 512
    tracks 160
    sectrk 9
    blocksize 2048
    maxdir 256
    skew 1
    boottrk 4
    os 2.2
    end

    # libdsk
    [sie3]
    description = SIE3 Siemens PG-635 - DSDD 3.5" - 512 x 9
    sides = alt
    cylinders = 160
    heads = 2
    secsize = 512
    sectors = 9
    secbase = 1
    datarate = DD

    # flashfloppy/GOTEK
    [sie3]
    cyls = 160
    heads = 2
    secs = 9
    interleave = 1
    bps = 512
    id = 1
    #rpm = 360
    rpm = 300
    rate = 250
    mode = mfm
    iam = no
    [/code]


    Larry

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)