Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Ms dos bootable usb flash drive

  1. Jan 2, 2012 #1
    Hello!! I have accomplished creating the USB boot able flash drive, That boots with DOS, I had thought this would be the perfect way to take control over the hard disk when my Operating system is corrupted.. But it's not. On the Dos windows drive c: is shown but I don't think that's my hard disk since no files in it as i type dir... On top of that no any other drive is detected example the CD drive.. When type d: then enter it's invalid... What's wrong with this... It doesn't help me at all??
  2. jcsd
  3. Jan 2, 2012 #2


    User Avatar
    Gold Member

    You do realize that DOS ran out of steam over a decade ago since it was never upgraded to more than a 16 bit operating system. You mention "On the Dos windows drive c: is shown ..... ", so are you running DOS as a shell under Windows from your USB, or just straight DOS vesion 6.2 or less.

    Here is a site comparing hard disk drive formatting throught DOS and later.
    DOS on its own cannot read NTFS, and some have trouble with FAT32.
    If your hard drive is over 2Gb, DOS won't read it.
    VGA or SVGA was about tops for monitor resolution.
    Memory was 640kB, but with special drivers for extended and expanded memory you could up that higher - you do remember HIMEM.sys?
    You need a DOS driver for the CD.
    And etc, etc special DOS drivers for just about everything on your system. Some drivers are just not available, having never been written.

    If your computer operating system was Windows 98 or less, than DOS would function nearly OK, as that Windows still used the commad.com and other BIOS from DOS. DOS was still under the hood there so to speak.
    After that Windows used its own hybrid BIOS and/or a from Win 2000, NT, XP and on.

    You might try some Linux on your USB for a boot drive if you need a command line prompt.
  4. Jan 2, 2012 #3


    User Avatar
    Science Advisor
    Homework Helper

    Your OS should have a tool to make a proper bootable "recovery disk" on your USB. This might be an option on the OS installation disk, rather than something installed on the PC itself - making something like that available on the PC would be an obvious target for malware.
  5. Jan 2, 2012 #4


    User Avatar
    Homework Helper

    What do you plan to accomplish with a bootable flash drive? You could try "ulimate boot cd", which is a collection of freeware DOS like utilities that include some that can read / write FAT32 and NTFS partitions, but it would seem that the main thing you'd want is the ability to restore your OS.
  6. Jan 2, 2012 #5
    He friends! The computer tells me that NT Loader is missing.. And as I browsed for this error i had one of the option as to copy this file NT loader and NTDETECT.COM to drive c: And I thought by DOS this is possible. There is where I encountered the problem.. I had to do this cause the system repair by the windows XP disc wants to completely format the hard disk no option to repair... I don't even know why this happens sometimes.
    A challenge question? There's DOS still running even in windows 7, so do you really think DOS compatibility is really a problem here?
  7. Jan 3, 2012 #6


    User Avatar
    Homework Helper

    Is this a dual boot system? Vista and Windows 7 use BOOTMGR, while Windows NT, 2000, and XP use NTLDR. Link to Microsoft sidt for restoring NTLDR, it's for Windows 2000, but Windows XP should be the same.


    Note that you can also get a NTLDR error if you have multiple hard drives and the logical driver numbers have changed. This is controlled by your computers BIOS. Usually there's a BIOS setup option that lets you choose the "order" of the hard drives.
  8. Jan 3, 2012 #7
    That's not DOS. That's cmd.exe, a Win32 program that has the same commands as DOS with the extra hardware support of Windows NT(Windows 2000 and up), which means it can write/read to/from NTFS. DOS, on the other hand, doesn't have the same hardware support, and cannot write/read to/from NTFS.

    As for your problem, I would use a Linux live cd, like Xubuntu or something. You can use it to boot into a CD, mount the hard drive to view the filesystem (to see if anything's actually missing), if it exists; or try to fix it (with Test Disk), if it doesn't.
    Last edited: Jan 3, 2012
  9. Jan 3, 2012 #8
    Having a recovery method is always a good thing and you are on the right track in wanting to have a bootable flash drive with the correct tools to fix problems

    That said, there's MUCH better ways to accomplish what you are trying to do.
    Try this

    avoid all the problems and stress related hair loss that comes prepacked with DOS
  10. Jan 21, 2012 #9
    Thanks a lot guys, I think I should get rid of DOS. No one has supported it at all!!
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook