The Hyperion shipped with a special version of MS-DOS. The first thing that is seen when booting is a graphical display of the Hyperion logo, which is a circle with the filled five-pointed star in it. The boot messages are:
Hyperion (TM) Copyright 1983 Dynalogic Info-Tech Corporation IO-SYS version 1.02E MS-DOS version 1.25H Copyright 1981,82 Microsoft, Inc.
The DOS reserves part of the machine's memory for a RAM disk (C:) and copies some commands into it. It also defines function keys and shows reminders of the functions at the bottom of the display in inverse text. While booting, the system reports the date, and the time is kept updated at the bottom of the display with the function key reminders.
This version of MS-DOS will search all available disks for a file if it is not found on the specified drive. So if I am logged into C:, and I type in the name of a program that does not exist in the RAM disk, it will search for the program on A: and B: in turn.
This version of DOS also includes a simple help system called "EXPLAIN", which provides information on how to use some of the DOS commands.
The MODE command configures the system. This program allows the user to select 40 or 80 column mode, IBM or Hyperion screen attribute interpretation, Monochrome or Color screen memory mapping, and other display features. It also controls the settings for the serial and parallel ports, and the size of the RAM disk (0K, or from 40K to 160K).
Of course, there are no directories with this early DOS version. :-)