MKBT Make Bootable v1.3

Create any boot- floppy/image from any win32 platform with any media size...

Page index

What is MKBT?
Download
On what platforms can MKBT be run?
What is the command line syntax?
What is so unique about MKBT?
Are there any other bootsector installers?
Where can I find the latest version?
How to build a bootable floppy
How to build a bootable floppy image file
How does MKBT work? (technical)
Bootsector installation
Bootsector copy (-c)

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What is MKBT?

MKBT is used for transferring bootsector between floppy drive, floppy imagefile or bootsector file. You can transfer in any direction.

MKBT is freeware!

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Download

To download MKBT use this link: MKBT v1.3

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On what platforms can MKBT be run?

MKBT is compiled as a win32 executable and runs on:

Windows 95/98/ME
Windows NT4/2000/XP

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What is the command line syntax?

Usage: mkbt [switches] <source> <target>

<source>	The source file/drive which contains the bootsector to install
<target>	The target file/drive to install the bootsector on

Switches:

-v	Verbose mode
-c	Copy bootsector (no install) used for copying the bootsector from floppy to bootsector file
-l<xxx>	Set Volume Label to <xxx>

Examples
To install bootsector from file "bootsect.bin" onto drive A: mkbt c:\os\dos622\bootsect.bin a: To install bootsector from file "bootsect.bin" onto floppy image "288.img" mkbt c:\os\dos622\bootsect.bin c:\tmp\288.img To copy bootsector from a bootable floppy in drive A: to a file called "bootsect.bin" mkbt -c a: c:\os\dos622\bootsect.bin

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What is so unique about MKBT?

Unique things about MKBT are:

It supports transferring a bootsector to floppy images. This allows you to create a bootable 2.88MB floppy image without needing a 2.88MB floppy drive. See How to build a bootable floppy image file
It is a win32 executable (not Dos)

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Are there any other bootsector installers?

Yes, I've found one other bootsector installer, "bootable.exe" written by Alexei A. Frounze. It is a Dos executable and only supports transferring a bootsector from file to floppy drive (A: or B:).

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Where can I find the latest version?

The latest version can be found on http://www.nu2.nu/mkbt

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How to build a bootable floppy

You can use any Dos version, any Dos supported floppy disk size to build your bootable floppy. For each Dos version you must have the following 4 boot files:

The bootsector in a file called "bootsect.bin"
You can capture the bootsector to a file using: mkbt -c a: bootsect.bin
IO.SYS (or IBMBIO.COM for Novell Dos)
MSDOS.SYS (or IBMDOS.COM for Novell Dos)
COMMAND.COM

For this example we will use MS-Windows 98 (version 4.10.1998), therefor we put the files in a folder called "4101998". They must have "normal" attributes (not hidden/system/readonly!).

You can now use makeboot.bat (which is include with the MKBT download zipfile).
makeboot.bat takes one parameter, that is the directory where the Dos bootfiles can be found.

Example: makeboot c:\os\4101998
or when your in the "c:\os" folder, just makeboot 4101998

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How to build a bootable floppy image file

Besides the 4 bootfiles you need as in How to build a bootable floppy you also need Winimage v5.x (the shareware version will do).

Start winimage, press Ctrl-N, to create a new image. Select a standard diskette format from the list (don't use any non-standard formats). For example "2.88MB".

Press Ctrl-S, to save the image, enter a filename, for example "288", and set save as type to "Image file *.IMA".

Close winimage (to not enter a label!).
Transfer the bootsector using MKBT.
For example: MKBT c:\os\4101998\bootsect.bin d:\tmp\288.ima
Start winimage again and open the file 288.ima
Press Insert to inject the file "IO.SYS" (or IBMBIO.COM for Novell Dos)
Press Insert to inject the file "MSDOS.SYS" (or IBMBIO.COM for Novell Dos)
Press Insert to inject the file "COMMAND.COM"
You can now label the image
Add any custom files or folders, using the "image" menu options
Save the image (Ctrl-S)
Done, you can use this image as a bootimage on bootable CD-Roms (see also Bart's way to create bootable CD-Roms)

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How does MKBT work? (technical)

MKBT copies parts of the bootsector. The bootsector, the very first sector of a floppy disk, is 512 bytes long and looks like this:

FAT Boot sector
Offset	Length	Meaning
0x0	3 bytes	Jump instruction
0x3	8 bytes	OEM Name
0xB	25 bytes	BIOS parameter block
0x24	26 bytes	Extended BIOS parameter block
0x3E	448 bytes	Bootstrap code
0x1FE	2 bytes	End of sector marker

The BIOS parameter block and extended BIOS parameter block contains the information:

BIOS parameter block for FAT volumes
Offset	Length	Meaning
0xB	2 bytes	Bytes per sector
0xD	1 byte	Sectors per cluster
0x0E	2 bytes	Reserved sectors
0x10	1 byte	Number of FATs
0x11	2 bytes	Root entries
0x13	2 bytes	Small sectors
0x15	1 byte	Media type
0x16	2 bytes	Sectors per FAT
0x18	2 bytes	Sectors per track
0x1A	2 bytes	Number of heads
0x1C	4 bytes	Hidden sectors
0x20	4 bytes	Large sectors

Extended BIOS parameter block for FAT volumes
Offset	Length	Meaning
0x24	1 byte	Physical disk number
0x25	1 byte	Dos: Current head NT: Dirty flag
0x26	1 byte	Signature
0x27	4 bytes	Volume serial number
0x2B	11 bytes	Volume label
0x36	8 bytes	Filesystem ID

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Bootsector installation

Below are the steps MKBT takes to install a bootsector:

Steps for bootsector installation
Step	Source sector	Buffer 1	Buffer 2	Target sector
1.	Read source sector in buffer 1
2.			Read target sector in buffer 2
3.		Transfer bootsector parts from buffer 1 to buffer 2 Jump instruction OEM Name Extended BIOS parameter->Volume label Bootstrap code End of sector marker
4.			Write buffer to target sector

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Bootsector copy (-c)

MKBT v1.3 (and higher) copy bootsector option copies the complete bootsector!
(previous versions only copied those sections that where needed to install it)

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