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Program BootDisk

Command line utility BootDisk can be used to transfer an application to a bootable floppy, disk, or floppy disk image file. The target disk must have been formatted with a FAT-12/16/32 or exFAT file system. The application to be placed on the disk must contain the BIOS boot code Biosboot.exe and a sufficiently large disk buffer. To invoke BootDisk, use command line:

BootDisk [Options...] AppName Drive[:] [BIOS_ID [Loader]]

or

BootDisk /remove Drive[:]

or

BootDisk [Options...] AppName[.rtb] Image.dsk [BIOS_ID [Loader]]

Options

/y

Yes. Replace hard disk boot sectors without asking.

/del

Delete all existing .RTA files from the target drive before writing a new one. If not specified, existing .RTA files are erased at the end of the operation.

/chs

Force the boot loader to use CHS instead of extended BIOS int 13h functions which use LBA sector addressing. This option should only be used when the target's BIOS uses a different CHS-LBA translation than the computer on which the bootdisk is created. It cannot be used on disks larger than 8G bytes.

/lba

Force the boot loader to use LBA instead of CHS BIOS int 13h functions. This option may be required for USB or CD-ROM boot disks which are emulated as floopy disks by the BIOS. By default, floppies are accessed using CHS BIOS functions.

/nopar

This option instructs Bootdisk not to update the partition table entry of the partition hosting the specified target drive. If not specified, Bootdisk will attempt to set the partition active.

/remove

When option /remove is specified instead of an application's name, BootDisk will delete all .RTA files from the target drive and restore the original boot sector which was saved by BootDisk in file BOOTSECT.RTT the first time it wrote an RTTarget-32 application to the disk.

Parameters

AppName[.rtb]

The name of the program to write to the target drive. If no path information is given, the .RTB file is searched in the default directory and then in the directory Bootdisk.exe resides in.

Drive

The logical (not physical!) drive to receive the boot image. It must be a primary partition.

Image.dsk

The name of a floppy disk image file Bootdisk should create. The file extension must be .img, .ima, or .dsk. When an image file is specified as the target device, BootDisk will create an image of a 1.44MB floppy disk formatted as FAT-12 and place the .RTA file on that image. Such image files can be used to create other boot devices such as bootable CD-ROMs. Creating disk image files is only supported when Bootdisk is executed under Windows.

BIOS_ID

Specifies the BIOS ID byte the bootstrap loader should use during booting to load itself. If not specified, default value 255 is assumed and the boot loader will use the value supplied by the BIOS. To force a specific boot device (may be required on some older BIOSes), use 0 for drive A:, 1 for B:, 128 for C:, 129 for D:, etc.

Loader

The file name of an MS-DOS .EXE file which will load the application from disk at boot time. When this parameter is not specified, the disk loader built into Bootdisk.exe is used. The source code of the default disk loader is contained in file Boot\Diskload.asm. Instructions to recompile and link the disk loader are given in files Bin\Makeboot.bc and Bin\Makeboot.ms.

Program BootDisk will write the boot sector, a disk loader program, and the application to a file named Application.RTA (RTTarget-32 Application) in the target drive's root directory.

BootDisk will check that the file written is located in a single, contiguous chain of clusters. This is required because the disk loader code is unable to load fragmented files. If the check fails, delete all files on the target drive and try again (sometimes, simply trying again without deleting any files will also work). Please note that Bootdisk cannot guarantee that DOS or Windows creates a contiguous file. On heavily fragmented disks, it may become necessary to defragment or reformat the target drive before DOS or Windows will write a contiguous .RTA file.

Disks prepared by BootDisk are standard FAT/exFAT disks and can be used to store other files on them. However, you should never delete an .RTA file and you should never use any method other than BootDisk or function RTMakeBootDisk to write an .RTA file. If you wish to use the diskette for other purposes, restore the original boot sector with

BootDisk /remove Drive[:]

or reformat it using FORMAT, or run SYS on it to write a new MS-DOS boot sector to the disk.

RTTarget-32 in conjunction with RTFiles-32 also supports writing boot images to a disk under program control using function RTMakeBootDisk described in the RTTarget-32 Reference Manual. Since function RTMakeBootDisk uses RTFiles-32 instead of DOS or Windows to write the target .RTA file, it can guarantee that the file is contiguous as long as at least one cluster chain on the drive is large enough to hold it.

Booting from Disk