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I just made a bootable DOS floppy disk in Windows Vista, but the files are taking too much space. I need more space to store a flash utility program and a ROM file. What files can I safely remove and still be able to boot into DOS?

In a way, what I am asking is really what the function is of each of the files, so that I myself can decide if it is worth keeping or if I can do without it.

Here is a list of all the files on the disk, sorted by size in Bytes in ascending order.

Size    Name
===================
116 736 IO.SYS
 93 040 COMMAND.COM
 58 870 EGA2.CPI
 58 870 EGA.CPI
 58 753 EGA3.CPI
 34 566 KEYBOARD.SYS
 31 942 KEYBRD2.SYS
 31 633 KEYBRD3.SYS
 29 239 MODE.COM
 21 607 KEYB.COM
 17 175 DISPLAY.SYS
 13 014 KEYBRD4.SYS
    115 AUTOEXEC.BAT
     33 CONFIG.SYS
      9 MSDOS.SYS

I don't remember seeing this many files when creating a bootable DOS floppy disk. It's as if Windows Vista adds some extra files for added functionality, when compared to previous versions of Windows.

I am pretty sure that COMMAND.COM is for keeping. But what about IO.SYS? That one alone takes a lot of space. And why are there three different SYS files for keyboard? Is that for setting different keyboard layouts? What are those CPI files and why are there three of them as well? I know what Autoexec.bat is for. If I add my command in there, can I get rid of COMMAND.COM?

The disk is a 2HD, double sided, 1.44 MB. I need 1024K plus another 26K of free space.

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  • use fformat tools old-dos.ru/files/file_241.html and boot floppy image.
    – STTR
    Commented Jun 6, 2015 at 0:00
  • Is that an external command in Windows Vista? I will have look at downloading a bootable floppy disk image. But would you not need an additional program to copy the image to a real floppy? It would be nicer if I could build one myself using built-in tools in Windows, rather than relying on others to do the job for me and also having Internet access at all times to download the needed files.
    – Samir
    Commented Jun 6, 2015 at 0:08
  • Don't get me wrong, you have a valid point. But I would prefer to use the tools at my disposal and perhaps learn a thing or two in the process.
    – Samir
    Commented Jun 6, 2015 at 0:13
  • sample: rmprepusb.com/tutorials/winimage Image: vetusware.com/category/OS/?cat=1&page=9 WinImage: winimage.com Tool: ultimatebootcd.com more: schierlm.users.sourceforge.net/bootdisk
    – STTR
    Commented Jun 6, 2015 at 0:42

1 Answer 1

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At the very least you need command.com, io.sys and msdos.sys. The character set (codepage), keyboard layout and display localization support files can all be omitted if they're not required. Delete everything else other than those three and try, or else use a DOS/FreeDOS USB stick (created using something like Rufus) if the PC can boot from it.

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  • Alright, I will test it as soon as I can and get back to you. But what do you make of the other files? And why does the IO file have to be that big? In relative terms... we are counting KB only, in year 2015. And is it not enough with one CPI file and one SYS keyboard file? I am just curious.
    – Samir
    Commented Jun 6, 2015 at 0:17
  • You can do without all the CPI and keyboard SYS files if all you want is the default layout (en-US I believe). As for why io.sys is that big, you'll really need to ask MS why they couldn't bring the size down further even though it's coded in assembly. Perhaps FreeDOS' version is smaller but I cannot compare right now. Why not use a USB stick? How old is this PC you're trying to boot using an actual floppy in 2015?!
    – Karan
    Commented Jun 6, 2015 at 0:20
  • @Karan to mini hardware boot tools) And do massive multiboot CD.
    – STTR
    Commented Jun 6, 2015 at 0:43
  • @STTR: Yes, of course a CD or USB would be better. Whether multiboot is required is for the OP to answer. Doesn't seem that way though. From what I can tell he simply wants to update his BIOS.
    – Karan
    Commented Jun 6, 2015 at 0:46
  • I find it historically amusing that @sammyg thinks io.sys is "big."
    – Carey Gregory
    Commented Jun 6, 2015 at 1:59

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