China DOS Union

### 486/Pentium Desktop PC
**Motherboard IDE Connector Connection:**
IDE1: Original machine hard drive　　　　IDE2: CF card (card holder)

**Objective:**
Sometimes boot with the original machine hard drive (3G, Win95).
Sometimes boot with the newly installed CF card.
If the method of plugging and unplugging to exchange IDE cable heads is adopted, the case needs to be opened, which is too troublesome.
Hope that after the hardware is connected and unchanged, use a soft method to switch the Primary/Secondary mode of the hard drive and CF card. In order to facilitate the alternate boot of the hard drive/CF disk.

**How to set the hard drive jumper and BIOS to realize the soft method to switch the boot disk?**

[ Last edited by proof on 2021-3-4 at 20:15 ]

Jumper is impossible.
BIOS is also impossible. Don't say for machines at the 486/586 level, the function of letting you press a shortcut key to bring up the boot menu during startup is probably something that appeared after UEFI came out. If you adjust the boot order by entering BIOS, it's probably something that appeared after machines at the Pentium III or 4 level came out.
You can try the software method with System Commander. If you want to boot from the "second hard disk", see if setting to boot from the "second hard disk" and hiding all partitions of the "first hard disk" will work. I don't think it's feasible because even if you hide all partitions of the "first hard disk", you can't hide the "first hard disk", so DOS will still think the "first hard disk" exists.