Unusual Dual-Boot, Real-Time OS (not yet installed) + Windows 7

I have a system that will run a Real-Time OS, normally installed on a FAT32 partition at the beginning of the hard drive. When the system was created, it made a 1GB Fat32 primary partition (for the RTOS) and a 104GB NTFS primary partition on which it installed Windows 7 (making this the System and Boot partition, as well).

I'd like to configure EasyBCD to have two entries -- Windows 7, which boots Windows 7, and RTOS, which makes Partition 0 (the RTOS partition) "active" and lets it do whatever. Note that when I turn this system on, now, it boots to Windows 7 -- I'm a little afraid to try to install the RTOS (which installs over TCP/IP, "finding" the remote machine through some magic process, then taking control, again by some means).

I figure if I can set up EasyBCD as described above, when I initially boot the RTOS, it will (of course) "do nothing" because its partition is empty, but after the RTOS is installed, I'm hoping it will "do the right thing" and start it executing.

Hmm -- let me look at a "pure" RTOS system and see if there are "significant" files placed on C:\. Well, there is an executive, ph_exec.exe, on C:, and a .ini file or two. Can't tell with this system if there are hidden files.

Any suggestions on how to proceed? I think if the RTOS choice basically "hid" Partition 1 (Windows 7) and let Partition 0 "do its thing" (which initially would be "do nothing"), this might work, but I'm uncertain how to set this up.


Mostly Harmless
Staff member
NeoGrub can do all that for you, and is very customizable.
I appreciate that (I read the Wiki), but it was not clear how to set it up to simply "expose" a partition (that does not yet have an OS installed). I found examples to hide one OS and boot another, but how about simply hide/expose one OS? I'd appreciate your comments on the script below.


#RTOS/FAT32 in Partition 0, Windows 7/NTFS in Partition 1

default 0
timeout 10

title RTOS (Hide Windows 7)
hide (hd0,1) # Hide NTFS
# What do I do here? Right now Partition 0 is blank -- I want it to
# "boot" as it normally would ...
# Do I just say "boot"?

title Boot Windows 7 (unhide Windows)
unhide (hd0,1) # Partition 1


Mostly Harmless
Staff member
title RTOS 
hide (hdx,y)
rootnoverify (hdx,z)
chainloader +1

title Windows 7
unhide (hdx,y)
Depending on how your RTOS works, you *may* need to make the partition active (makeactive). However, if you do so, BOOTMGR will not load on next reboot -> no NeoGrub -> no way to get back into Windows. You'd need to install a *second* copy of GRUB to the RTOS partition and use that to undo the changes made by that menu. Usually, though, that is not necessary. Hopefully you will get away with just chainloader+1