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Writing and reading PC9801 disk images for real machines

Discussion in 'NEC PC-88 and PC-98+ PC-FXGA' started by Jamtex, Oct 31, 2012.

  1. Jamtex

    Jamtex Adult Orientated Mahjong Connoisseur

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    Found this document I was working on back in 2007. I updated the links so that they work.

    Backing up and recreating discs from the PC-98x1 to Windows and back again. The X680x0 and FM towns use similar disk file systems and you can use this information to make real disks for these machine using the information below.

    If you have a PC-98x1 machine and you have some games you may want to back them up or even run game images (from your back ups or for er other sources), you also might want to create a boot disc for your machine if the seller decided helpfully to reformat the hard drive to delete all their details before sending it to you so you just get a "NO SYSTEM FILES" message on booting.

    There are two ways to do you can this, one is to use a USB (or Firewire) / 2.5" Hard Drive adaptor (you could use internal adapters but I would not due to the hassles it can bring) and copy the files over using DISK EXPLORER. The other way is to use a floppy drive to copy images over.

    We'll look at the floppy method first as it is the easiest way to copy straight images and doesn't require you to remove the hard drive from the machine.

    For this you will need three programs.

    DISK IMAGE (http://www.vector.co.jp/soft/dl/win95/util/se076285.html)
    VIRTUAL FLOPPY IMAGE CONVERTOR (http://www.vector.co.jp/soft/dl/win95/util/se151106.html)
    and
    DISK EXPLORER (http://hp.vector.co.jp/authors/VA013937/editdisk/editd169e.rar)

    You will be using the command prompt a lot so I suggest you find it. For ease of use create a PC9821 folder on your C drive and put each of these program in it's own folder, they just need to be unzipped no installation required. I also suggest making an Image Folder so you can put each of the disc images into.

    The PC-98x1 series uses a weird 1.2MB disc format (some people call it 1.22MB, 1.23MB or 1.25MB, but these are all the same). The reason for this was to keep compatability between 5" (5.25") discs and 3.5" discs. You could use the DISKCOPY command between the two formats and get an exact copy (not something you could do on a western PC). However a number of disc drives in Western computers may not read / write 1.2MB discs correct.

    If you have a USB floppy drive (or if you don't have any floppy drive then buy a USB floppy drive) then it is more then likely compatable. All the USB drives I have tested, which include HP, IBM, Fujitsu and a no name model have all worked fine (including drives bought in America).

    A quick test would be to open up a command prompt in Windows (click Start, programs, accessories then command prompt or click Start, Run, then type CMD in the box and enter), put a 1.44MB floppy in the drive (you have plugged it in haven't you?) and then type

    FORMAT A: /A:1024 /T:77 /N:8 /U

    (Note A: might be different but to confirm, click My Computer, it should tell you the drive, if it doesn't then click once on Floppy Disk Drive and then click properties and click Sharing)

    It should format the disc in PC-9801 format of 77 Tracks, 8 Sectors per track, 1024 Bytes per track on sector, if it comes up with errors like Track 0 unreadable then try another disc, if that fails then the drive is not compatable. Else it should finish and say something like (this is from Windows Vista).

    C:\>format a: /a:1024 /t:77 /n:8 /u
    Insert new disk for drive A:
    and press ENTER when ready...
    The type of the file system is FAT.
    Verifying 1.23M
    Initializing the File Allocation Table (FAT)...
    Volume label (11 characters, ENTER for none)?
    Format complete.

    1,250,304 bytes total disk space.
    1,250,304 bytes available on disk.

    1,024 bytes in each allocation unit.
    1,221 allocation units available on disk.

    12 bits in each FAT entry.

    Volume Serial Number is 0487-2775

    Format another (Y/N)?

    Then your drive is compatable, if you are going to make images then I suggest you format your discs first so type Y and continue. The /U switch is important as it will format the disc unconditionally, without it you might find the discs won't format correctly.

    We will recreate the MS-DOS 6.2 installation discs, but any image file will work in exactly the same way.

    Download the disc images from here

    http://www.initialm.net/mkw/pc98catalog/tool/PC98_MSDOS62.rar

    You will need a program to unrar the file, use 7z or unrar or something.

    Then open the file into your Images folder (I created a MS DOS 6.2 folder for it). The files will be in .FDI format and need to be converted.

    Load up VFIC and select BKDSK FORMAT from the drop down menu and then just drag and drop each of the .FDI files into the window that says "Drag & Drop File(s) Here to Convert", it will create some new files that have the exention .HDM which is a plain image format.

    Next load up Disk Image, click the "+" tab and uncheck skip error track, click "for old pc-dos users" and make sure you set the Windows option for your machine, either 95/98 for Windows 95, 98 or ME or Xp/2k for Windows XP, 2000, NT4 and Vista, also set FD Drive to the drive you will be using and FD Mode to 1.25M, anything else will work but will fail to work on the PC-98x1 machine.

    Click HD -> FD (125) and select the first .HDM file, and click okay and it should then write the disc, if you did not format the disc to 1.2MB with the format command then the disc will probably fail to write correctly. Once done, open up a command prompt and type

    DIR A:

    (Replacing A: if different) and if successful it should list the files. The PC-98x1 should recognise the disc too.

    Using the disc you can install an operating system on the drive if you get the dreaded NO SYSTEM FILES (Although check to make sure you do have a Hard Drive in the the Hard drive bay).


    Making images is very easy, make sure your drive is compatable by testing it (see above) first. Then you need to check the condition of your discs. I suggest you don't put it into your PC-98x1 drive as if the disc is faulty then you could mess up the drive and it's easier to replace a USB drive then a notebook drive.

    First check the discs to make sure they are not damaged in any way, like cracks or chips to the disc or the metal slider is bend or dented. Also check the metal slider by touching the top right hand part of it to make sure it will slide left and springs back when you move your finger right if unsure then don't use the disc as it'll cause you problems.

    Slide the metal cover again and under decent light, check to see if the brown surface of the disc is reflective and doesn't have any marks, if the disc looks to have water marks or isn't totally reflective then the disc may be damaged and don't use it, you still of course could try but again do it on a USB drive that you can replace.

    *IMPORTANT* make sure you always write protect the disc before inserting it into the drive.

    Open up the command prompt and type DIR A: to check that the disc is readable if your drive makes funny noises then I suggest you press the eject button, also PC-9821 discs may be in 1.44MB format and if this is the case then

    Create a folder in the images drive to store your images, just so you can find the files easily.

    Next load up Disk Image, click the "+" tab and uncheck skip error track, click "for old pc-dos users" and make sure you set the Windows option for your machine, either 95/98 for Windows 95, 98 or ME or Xp/2k for Windows XP, 2000, NT4 and Vista, also set FD Drive to the drive you will be using and FD Mode to 1.25M.

    Click FD -> HD (125)

    Move to the correct folder and type in a name, it's useful to call the discs as they are called on the disc as well as using a numeric or letter first so you can idenify the discs easily. So for example DISK A, DISK 1 - SYSTEM DISK, DISK 1, DISK 1 - GAME DISC, DISK 2 - DATA DISC etc) then add the extention .HDM (as the program won't). Then click OK and it will read the disc, if it comes across errors retry them a few times, maybe take the disc out and reinsert it, if it continues to fail then give up as the disc is unreadable.

    I would open the created image in DISK EXPLORER as it will show if the disc has copied correctly (ie you can see files, click VIEW and DISK VIEW. to see it has copied as a 1.2M disc (it should have 1,250,304 bytes on the disc).

    Repeat this for all the discs and then you have a back up, you can use VFIC to convert the discs into other formats like .FDI for use in emulators if you so wish.
     
  2. bombman

    bombman Rising Member

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    Thank you so much for all this information.
     
  3. SkyeWelse

    SkyeWelse Member

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    Jamtex, I pretty much joined this community for the sole reason of wanting to thank you for creating this guide. It's worked out very well and I'm now able to start playing newly written PC-98 games. The only part I'd want to mention that seemed to throw me and a friend of mine off when trying to complete the Disk Image program step of HDD -> FDD option was that we each had to leave skip error track checked or it in most cases would not write to the disk at all. I've written a few disks now and so far each one has mostly worked aside from one Dos 6.22 disk I had tried. I have two PC-98 Machines, the PC-9821 Ce2 S2D and the PC-98 DO (with 88 Mode for playing PC-8801 games).

    I plan on sticking around this forum to learn more and ask some more questions as I'm pretty new to figuring out how all of this stuff works on actual NEC PC-98 Hardware.

    Thanks again for your guide!

    Edit:
    Oh and one other detail worth mentioning. When my friend and I first started this process out, we were receiving "Parameter Not Supported" error messages with the USB drives we were using when trying to use them in Windows 8 and Windows 7. My friend was able to get this to work in XP first, but then later isolated that it doesn't necessarily need to be XP, but that it does need to be an OS that is 32 bit instead of 64 bit. The 64 bit was the main culprit of the Parameter Not Supported issue when trying to format disks.

    -Thomas
     
    Last edited: Aug 10, 2014
  4. MrAlextov

    MrAlextov <B>Site Supporter 2013</B>

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    Can someone rehost the MSDOS bootdisk for PC98?
     
  5. Dr.Wily

    Dr.Wily Peppy Member

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    Hello Jamtex,
    I has a PC-9801 UV with 2 3.5'' 2HD disk drive. Unfortunately your guide on backing up and recreating discs does not work. I have tried many solutions with no luck. I tested with many floppy drives (Samsung, Mitsumi, Alps, Sony, Teac). None was able to format at 1.23mb.
    What I did :

    With 3 mode floppy disable in BIOS and no specific 3 mode driver :
    - format from win7 : fail (drive does not support this mode)
    - format from xp / 2000 : unable to format (track 0 unreadable or others random errors)
    - format from japanese version of windows 2000 : same as xp/2000
    - omniflop : seem to be ok to format, but floppy disk is not recognized by PC-98 and unreadable by omniflop after formating.

    With 3 mode floppy enable in BIOS and HP 3 mode driver installed :
    - format from win7 : fail (drive does not support this mode)
    - format from xp / 2000 : unable to format. Format at 1.23mb starts and fail
    - format from japanese version of windows 2000 : I can see in format dialog box the 1.23mb /1024 option. But the format fails and I can't read PC-98 formated disk

    I modified a Samsung sfd-321b well know to have compatibility with 3 mode (by shorting OPA jumper to enable 3 mode). Fail again. I use 2HD 1.44 disks...
    I has nothing other than floppy disks to start this PC-98. And I cry in front of the screen helplessly seeing this poor n88 basic.
     
  6. sp193

    sp193 Well Known Member

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    I'm quite sure that it needs a real MS-DOS OS (i.e. Windows 98) to work.
     
  7. Dr.Wily

    Dr.Wily Peppy Member

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    Yes, Japanese Win98 has 3 mode support. With proper driver installed I was able to read PC-98 floppies. But Win98 can't format or copy at 1024 sectors. No way to format a disk, plus the "/a" option did not exist.

    If the disk is properly formatted (without system files), PC-98 say "no system file". It's means the disk has right format but without boot sector. I say this because sometime the format a: /a:1024 /t:77 /n:8 /u command seem to work (especially under Win2k/xp) but actually the disk is badly written. This kind of disk can't be read by a PC-98. PC-98's drive seeking for approximately 15s, after PC-98 displays "how many files" and run N88 basic.

    - correctly formatted disk without boot sector gives : "no system file"
    - faulty formatted disk give nothing and PC-98's drive is unable to read it. It's seek with a clatter sound.

    They must 3 things to format 3'5'' floppies at 1.23mb.

    - Your BIOS must support floppy 3 mode option
    - your drive must support 3 mode (300 / 360 rpm)
    - sometime, OS need a driver to enable 3 mode (in Win9x). Win2k/XP/7 have sometime a sort of auto-detection especially on USB drive. Native FDC controler on motherboard need a driver. But only few internal floppy drives support realy 3 mode out of the box. Usually 3 mode is an option on internal drive, and you must mod them to enable it.

    HP 3 mode driver for win2k/xp enable 1.23mb/1024 format directly in Windows GUI. But without a correct 3 mode FDC controller the formatted disk will be corrupt. Readable in Win2k/xp but unreadable on a PC-98.
     
    Last edited: Sep 10, 2015
  8. SkyeWelse

    SkyeWelse Member

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    Hi Dr. Wily.

    Welcome to the PC-98 hardware scene! Since you are kind of like my all-time favorite villain, (I'm a huge fan) I'm going to try and help you out if I can so you can get back to making your robot masters. :)

    I'm not familiar with the PC-9801 UV model so I can only really offer some general advice as far as that goes, but we'll see. I noticed your post over at NFGgames forums first and I immediately came back over there to link you to this very guide, but I see you've already found it.

    Would you mind telling us the models of your disk drives that you are using and are you using an internal fdd drive or a USB drive? I believe my friend Xalphenos and I each got ours to work just fine using a USB drive over the one I have that is internal. We followed Jamtex's process above aside from one small difference in that we each had to leave skip error track checked or it in most cases would not write to the disk at all. From what I read above if you tried WinXP, that is a 32 bit OS, so you've rule out the issue of "Parameter not Supported" being affected by 32-bit versus 64-bit.

    So what errors are you getting specifically? What does it tell you? And is this happening as you are attempting to format the disks? Also, dumb question, but you've made sure to have the write-protect flap set to disabled on the disk right?

    -Thomas
     
  9. MrF

    MrF Member

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    Hi Dr,
    I've been through the same grief myself recently, first I think the pc9801UV is different to the later models, it has FD1135D floppies but can only use them in 2DD mode, not HDD, so none of the guides worked for me.
    However, after much experimentation I have managed to create dos diskettes which boot my pc98.
    First, I format the 2dd diskettes with windows 7 in cmd because the gui formatter no longer supports 720. My bios has no mention of 3 mode support (its fairly modern MSI k8n motherboard) and the diskette is a generic alps unit, if I follow the guides around the net I get the unsupported format error on this hardware. But I type the following into cmd window to make a blank 720k floppy:-
    format a: /T:80 /N:9
    Then I load the Anex86 emulator with a dos boot image obtainable lots of places on the net as disk1, and open the following sodick system image diskette in the zip as disk2, and then I can format the image, put later versions of dos on there etc.
    Once I'm done with that, I use Disk Image 1.3b with skip error track ticked, and FD mode as 720k, and I write the edited sodick image to 2dd floppy using the HD->FD 720 button.
    This will then boot to a dos prompt in my pc9801UV.

    I think the sodick image is padded so it can be written without special tools under windows so its supportable, but it might just be my understanding wrong but I've attached a link to this post below with the disk image that I use. When I tried writing other images it doesn't work for me, but I'm just happy I have a working method finally.

    http://assemblergames.com/l/attachm...9/?temp_hash=d68e3cce1ddd4ef78faa315a8b95f285

    Hope this helps someone else.
     

    Attached Files:

  10. MrF

    MrF Member

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    Just on another point, I'm doing the above using 64 bit install of windows 7, and my floppy is on the floppy connector of the motherboard. I tried the mitsumi usb floppy + internal floppy following in the guides on a old xp machine with 32 bit install of windows and it didnt work for me, possibly because the usb firmware can only cope with HDD not 2DD as I coudlnt even format 720k diskette with it.
     

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