Bootdisk Tools License and Readme

8086/pc-baremetal/bootdisk/license.txt

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+Copyright (c) 2000-2015, Alexey Frunze
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this
+   list of conditions and the following disclaimer.
+2. Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+The views and conclusions contained in the software and documentation are those
+of the authors and should not be interpreted as representing official policies,
+either expressed or implied, of the FreeBSD Project.

8086/pc-baremetal/bootdisk/readme.txt

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+The "BootProg" Boot Sector
+
+
+What is BootProg?
+
+BootProg is a collection of 512-byte boot sectors (for the x86 PC) capable of
+loading and executing a program from a FAT12-formatted floppy or a FAT16/32-
+formatted hard disk (bootable USB sticks and CDs can also be made with
+BootProg).
+
+BootProg understands programs in the MS-DOS .COM or .EXE format. This makes
+it possible to use existing 16-bit compilers such as Borland/Turbo C/C++,
+Sybase/Open Watcom C/C++ and Smaller C and a variety of assemblers such as
+NASM, FASM, TASM and MASM among the others.
+
+BootProg doesn't require that the program occupy a contiguous span of sectors
+or FAT clusters or reside at a specific fixed location on the disk. BootProg
+faithfully parses the root directory and the chain of FAT clusters in order to
+locate the program contents. The only requirement is that the program be named
+"STARTUP.BIN" (without quotes). This makes updating the program easy. You just
+need to update the file and you can reboot and execute it immediately.
+
+
+What can BootProg be used for?
+
+You can make a boot loader for your OS. The program that BootProg loads can be
+your 2nd stage boot loader. Or, if your OS is relatively small, STARTUP.BIN
+could contain the entire OS.
+
+You can write low-level utilities to work with your PC's hardware and load them
+with BootProg without having to jump through the hoops with your Windows, Linux
+or even DOS.
+
+You can make cool graphics demos or games that run on bare hardware.
+
+
+What can't BootProg be used for?
+
+Many things. Most importantly, if you make a DOS program that uses any MS-DOS
+service functions (e.g. int 21h) or data structures, it will not work when
+loaded by BootProg. It must use either BIOS services (e.g. int 10h, int 16h,
+int 13h and such) or access hardware directly or both.
+
+However, it is possible to create universal/hybrid programs that would work
+both in DOS and when loaded by BootProg. BootProg will set registers si, di and
+bp to the values 16381, 32749 and 65521 respectively before transferring control
+to your program. Your program can then check the values in these registers and
+use DOS services in DOS or something else instead on bare hardware. You can also
+choose to make the program run with reduced functionality if not on DOS or
+vice versa.
+
+
+How does it work?
+
+Nothing special. It just finds STARTUP.BIN, loads it, performs any relocations
+necessary for the .EXE type of programs, sets the magic numbers 16381, 32749
+and 65521 in registers si, di and bp respectively and passes control to your
+program.
+
+If BootProg can't find STARTUP.BIN, it will print "NF" to the screen. If it
+fails to load the file due to a read error, it will print "RE". This is how the
+FAT12 and FAT16 versions of BootProg work. The FAT32 version has much less space
+for these errors and so in both above cases it will simply print "E".
+
+
+How do I put BootProg on my disk?
+
+If you have a 1.44MB 3"5 floppy, just format it regularly with FAT12 in DOS or
+Windows and then write flp144.bin to the very first sector of the floppy with
+whatever tools you find/have for that. After that you can copy STARTUP.BIN to
+the floppy and off you go.
+
+If you want to create an image of a 1.44MB 3"5 floppy, it might be even easier.
+Compile the mkimg144.c program contained here with your favorite C compiler
+and use it:
+
+  mkimg144 [option(s)] [file(s)]
+
+  Options:
+
+  -bs <file>  Specifies the boot sector to use, e.g. "-bs flp144.bin"
+
+  -o <file>   Specifies the name of the output file ("floppy.img" is the
+              default, if this option isn't specified)
+
+  -us         Uses the current time to set the volume ID of the FAT to a unique
+              value (the volume ID is used to distinguish between different
+              removable disks and detect disk change more accurately)
+
+E.g: "mkimg144 -bs flp144.bin -o flp144.img -us startup.bin".
+Btw, you can rename the supplied file "demo1.com" to "startup.bin" to try it
+out.
+
+For all other cases you'll need to become a little more familiar with FAT and
+a little more intimate with disk tools and BootProg's source code.
+
+You will need to populate the BPB's of boot16.asm and boot32.asm with the
+values appropriate to the type and size of the file system that you already have
+on a disk or that you intend to create on the disk.
+See the source code, these places are marked with question marks, for example:
+  bpbBytesPerSector       DW      ?               ; 0x0B
+
+The best is to format your disk with some standard tools (e.g. FORMAT.COM in
+DOS), extract the BPB values from the FAT-formatted disk, put them into BootProg
+and then write thusly adjusted BootProg over the original boot sector.
+
+You may find a disk editor handy when manipulating BPB values and/or
+reading/writing boot sectors.
+
+
+Limitations and implementation details
+
+boot12.asm (flp144.asm) and boot16.asm require an i80186/i80188/i80286 or a
+better CPU. boot32.asm naturally requires an i80386 or a better CPU.
+
+boot12.asm (flp144.asm) was not tested on hard disks (but it might work as the
+boot sector on FAT12 primary partitions (file system ID 1)).
+
+boot16.asm was written for and tested on primary FAT16 partitions (file system
+IDs 4 and 6). Its expected use is the boot sector of the partition and not the
+MBR. The FAT16 version may allocate up to 128KB of RAM for the entire FAT16,
+leaving less room for STARTUP.BIN. But ~400KB left should still be plenty of
+space for its code, data and stack.
+
+boot32.asm was written for and tested on primary FAT32 partitions (file system
+IDs 0Bh and 0Ch) and for BIOSes supporting function 42h of int 13h (IOW, for
+systems supporting HDDs larger than 8GB). Its expected use is the boot sector
+of the partition and not the MBR.
+
+BootProg does not check the size of STARTUP.BIN and reads into memory all of its
+clusters, which means that up to 32767 extra bytes may be read from the disk
+and written to the memory after the last byte of STARTUP.BIN (max cluster size
+is 32KB). It also means that you may append data to your program and it will be
+loaded. You may create oversized .COM-style STARTUP.BIN larger than ~64KB,
+however, note that the stack will naturally overwrite its contents from offset
+65535 of the program segment (offset 65279 of the file) downwards.
+
+If your PC has the full 640KB of conventional/DOS memory, you should be able to
+load program files of size of up to ~400KB.