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Instructions to make Bootable Dos CD

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  • Instructions to make Bootable Dos CD

    Note: this post turned out pretty long, so I will post more stuff and some helpfull links in the next post down.

    Hi to Mel, boot cd's are pretty easy. Well, he asked how, and I thought that this was relavent enough to bother sharing my experiences with you all. There is a lot of potential: CDs boot fast, and they are huge, and they are cheeeep!, and lot's of kewl little boxes don't have floppies any more (or so we thought , they are just hiding).

    I use Nero 5.x. Came with my Liteon CDRW. Nero is very common and popular (well earned rep IMHO). It has a very robust option to make bootable cd's. You can certainly use other programs too, but I based this example on Nero, since it has pretty much all the options available and covered. Here are some of the steps and details:

    the principal:
    -the ElTorito standard lets your bios see if there is a bootable CD in the drive. If there is the bios mounts the boot image from the CD as a drive to boot from.
    -a floppy bootable image is best (1.44 or 2.88 work well, but have fun making a 2.88 floppy image file), but larger hard drive images are not well supported by all CDROMs.
    -your CD boot image becomes A, your actual floppy drive becomes B.
    -the computer boots the virtual image that is A. 'A' can't see the rest of the CD until it is mounted with drivers as it's own drive (Y is my fave)(Y conversely doesn't see the virtual A), as per whatever operating system was on the image (micro linux thingys can be used too, even Win98 via Dos7 with some big tricks).

    in preparation:
    -work with whatever dos or os you like )
    -make up a good bootable floppy that includes a cdrom driver in the config.sys (oakcdrom.sys is very generic and compatible), and calls mscdex.exe in the autoexec.bat. I actually use a proggie called ctload in the autoexec.bat to load oakcd.sys and a few others, from outside of the config.sys. This allows for easier maintenance of the setup.
    -use a disk image program to make a .img file of the floppy (I keep my boot floppy image in the directory tree that I also burn onto the rest of the cd) , or you can feed the floppy to Nero each new burn.
    -you can have an 'extended' set of dos directories in your cd that become accessible after mscdex is running, and use this stuff from the rest of your autoexec.
    -a few seconds delay after running the oakcd.sys before running mscdex lets the CD spin up, and helpd insure a proper mount.

    when burning:
    -choose 'new compilation' and pick 'CD_ROM (boot)'
    -use ISO Level 1 => 8.3 filenames, do not relax any ISO restrictions except adding ';1' extensions.
    -use Mode1, not Mode2/XA
    -use Joliet, this adds a second whole directory of windoze long file names for, duh, windoze.
    -it's amazing what you can put on the rest of the disk ) I put a very enhanced dos, plus MANY dos utilities, plus Win98 (sure I own a liscence), plus MANY win32 apps (all freeware of course LOL). This is what I use to install Win98, and everything else I need. Or salvage a bummed HD, or back one up, or partition magic from dos , or... you get the point.

    Continued in next post

    What can go wrong will go wrong.
    Anything can go wrong.
    What hasn't?!?!
    What can go wrong will go wrong.
    Anything can go wrong.
    What hasn't?!?!

  • #2
    Continued from last post. Links in next post.

    Here are my config.sys and autoexec.bat for examples:

    device=emm386.exe 4096 ram
    buffershigh=15 /p /e:512 /l:128 /u:128
    really does very little, just himem and emm386, plus very explicit about how big & where things are.

    @echo off
    prompt $p$g
    ctload oakcdrom.sys /d:cd1
    choice /c:12 /n /t:1,3  A 3 second delay for CD's to be ready... 
    loadhigh mscdex.exe /d:cd1 /l:m
    :: check for successful mount of the rest of the cd...
    if not exist m:\dos\ goto nocd
    if not exist m:\help.txt goto nocd
    :: the cd is present so use it...
    set path=m:\;m:\dos
    set comspec=m:\dos\
    cd \ 
    echo +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=
    echo  You have two choices of what to do next...
    echo  1 = KEEP GOING!!! on with the AUTOEXEC.BAT and do handy things.
    echo      (Default, this choice is what you want to do usually)
    echo  2 = STOP STOP STOP!!! right here with NO MORE STUFF LOADED!
    echo      (Do this if things ain't right in DOS 'ville)
    choice /c:12 /t:1,30 Ya gets 30 seconds ta pick, hit SPACE ta get all day... 
    if errorlevel 3 goto deadend
    if errorlevel 2 if not errorlevel 3 goto deadend
    if errorlevel 1 if not errorlevel 2 goto therest
    goto deadend
    <snip>... pages and pages worth. I will put the works on my website, see next post.

    I know there is a lot of stuff here, but it makes sense. and set 50 and 25 lines on screen without ansi.sys and, pretty
    -ctload puts the oakcdrom.sys with the rest of the device type stuff.
    -choice is used for the delay.
    -mscdex mounts M:, I use Y: now (I have hit systems since with partitions past M, then CD gets bumped to a later letter and can't be found) (Y leaves room for a second CD, Z: ).
    -if exist tests for the the rest of the CD. I 'jump' out of A: asap, and use the rest of the CD on it's new drive letter, wich has a full duplicate \dos directory, and can be bigger than we ever dreamed of in 1990.
    -the rest I left there just to show off my pathetic dos batching ability. Works well though

    I hope this helps more than confuses. It sure took me a while to figure this stuff out on my own (thank god for google).

    What can go wrong will go wrong.
    Anything can go wrong.
    What hasn't?!?!
    What can go wrong will go wrong.
    Anything can go wrong.
    What hasn't?!?!


    • #3
      Here are some handy things to round this contribution up has the most amazing universal dos boot floppies.
      I learned very much from these. This .zip has the core stuff from my boot CD. You will need to change the autoexec.bat and other things too, but it has most of what you might need to get going.

      -Unzip the file WITH paths to a new folder. You will get:
      \dos\....      a reasonably packed and rounded dos 7.0 plus [b][i]Very Handy Extras![/i][/b]
      \bootdisk\.... has some floppy images, 'noems.img' and 'yesems.img' (different config.sys),
                     which you feed to Nero, and becomes A: while booting this CD.  Point Nero at your 
                     customized version of this file for your boot disk, since my autoexec.bat
                     is set up for my CD's contents.
      -I include all this stuff right on the root of my CD. Remember that while the CD is in the drive (while you are booting) the image file of your boot floppy is available on A:, but I duplicate all that plus more, and use the newly mounted CD drive (M: ) asap for my dos drive.

      -check out the autoexec.bat, it makes a ramdisk on X: and copies dos to it: free the CD!

      Hope you all have fun! Good luck and happy burning!

      I want to now give the disclaimers and appologies. I have recent PC Cillin virus checked clean, tell me if I'm contaminated. My boot CD was a personal project to help me maintain about 10 pc's between me and my friends. This is not commercial in any way, just handy. I have lots of other peoples software here. Go get it it yourself and make sure you are allowed to use it. Thanks go to them for all the handy tools. Everything here was found netside or made by me, I'm not wanting to rip off anyone, just be useful

      What can go wrong will go wrong.
      Anything can go wrong.
      What hasn't?!?!

      [This message has been edited by Criss French (edited March 29, 2004).]
      What can go wrong will go wrong.
      Anything can go wrong.
      What hasn't?!?!


      • #4
        Thanks a lot for the info, Chriss. I'm kind of busy right now
        doing an emergency engine rebuild for someone but I will try it
        as soon as I can. Thanks again.

        There are no atheists in a fox hole or the morning of a math test.
        If my flag offends you, I'll help you pack.


        • #5
          BTW, I have a friend who has made many, and much more sophisticated boot CD's than I. He does network detection, scsi support, etc. He does all his 'proofing' on CDRW's, so when that one line goes wrong in the autoexec, he just wipes the disk and starts over. You still have to burn a generic ISO format data cd, not a directcd type format, but at least it's not a coaster for the sake of one bum line.

          He also uses Winimage to build his 2.88mb floppy images, giving him more space right on the virtual A drive (but he doesn't have a real 2.88 floppy drive). I just make a real boot floppy (1.44mb) all fancy like, boot with it for testing the code, and when it works I image it with di.exe (from \bootdisk\) and then burn the boot CD. Ususally works no problem, though I did make a couple of coasters before I found out about the small delay between doing the oakcd.sys and starting mscdex.exe. What would happen is I would always get errors b/c the CD drive hadn't spun up yet, so didn't respond to mscdex (i think anyways). I still get the odd error on a really slow cd, maybe another 5 second delay after the mscdex would fix it.

          What can go wrong will go wrong.
          Anything can go wrong.
          What hasn't?!?!
          What can go wrong will go wrong.
          Anything can go wrong.
          What hasn't?!?!


          • #6
            For compatibility with older CD drives-- your burner should have an
            option like "burn image at once and close". Older drives don't
            support the multi-burn option that lets you add files later (if
            space allows), so you may need to turn that off.

            Tom Hanlin
            PowerBASIC Staff