China DOS Union

The main reason I removed the SYS command was to prove that ROM-DOS.SYS is simply not a core file of ROM-DOS at all.

It really isn't. When making a boot disk with DISKTOOLS, only the three core files are needed. But it's strange, why does the SYS command need ROM-DOS.SYS?

ROM-DOS probably does it this way for convenience too. That way, with only ROM-DOS.SYS and COMMAND.COM, you can use the SYS command anywhere to complete the transfer-system operation.

This is what is written in the ROM-DOS 6.22 manual:
“……The /S switch causes FORMAT to copy the ROM-DOS system files, ROM-DOS.SYS and
COMMAND.COM, onto the disk. The file ROM-DOS.SYS is renamed and stored on the disk as
files IBMBIO.COM and IBMDOS.COM, which are stored as hidden files, unless the /H option is
used.……”

The following is the introduction to the SYS command in the ROM-DOS 7.10 user manual:

The SYS command copies the ROM-DOS system files ROM-DOS.SYS and COMMAND.COM from the disk in the default drive to the disk in the specified drive.
The file ROM-DOS.SYS is renamed and stored on the disk as files IBMBIO.COM and IBMDOS.COM, which are stored as hidden files.

Use the SYS command to transfer the ROM-DOS system files to a floppy disk or hard disk. The disk can be a formatted blank disk or can contain files; it is not necessary for the system files to be the first files on the disk. The only requirement is that there is enough contiguous free space on the disk for the new system files to be placed. If the disk already contains system files, installing the new system files deletes the existing files. The command processor, COMMAND.COM, is also transferred to the disk and does not need to be copied into the same contiguous space as the system files.

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