Commodore PC Ms-Dos 3.2 User's Manual page 162

90 MS-DOS User's Reference
Sys (System)
Updating your system
Sys
Purpose:
Transfers the ms-dos system files from the disk in the default drive
to the disk in the specified drive.
Syntax:
sys drive:
Comments:
Usually, you use the sys command to update your system or place
it on a formatted disk that contains no files. You must type a drive
letter with this command.
If the system files io.sys and msdos.sys are already on the target
disk, they must take up the same amount of space on the disk as
the new system will need. This means that you cannot transfer
system files from an ms-dos 2.0 disk to an ms-dos 1.1 disk; instead,
before the sys command will work, you must reformat the ms-dos
1.1 disk with the ms-dos 2.0 format command.
The target disk must be completely blank or must already contain
the system files io.sys and msdos.sys.
The transferred files are copied in the following order:
ID.SYS
MSDOS.SYS
Io.sys and msdos.sys are both hidden files that do not appear
when you type the dir command.
Sys does not transfer the command com file (the command pro
cessor). So to transfer command.com to the target disk, you must
use the copy command.
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