Dual-Boot PC w/ Toggle Switch

This is a project that I had planned on doing when I first built my new PC about a month ago. I have used software dual-boot computers before and while it can be handy I found the negatives to be too great to continue on that path. In order to dual-boot Windows and Linux you first install Windows in its own partition and then install Linux in a separate partition. In this arrangement you use the Linux bootloader to choose which OS to run on startup. This works fine unless you have to reinstall Windows; which as we all know needs to be done from time to time. Windows will then overwrite your Linux bootloader making your Linux partition inaccessible. While it is true that you can modify the bootloader to access Linux or reinstall the Linux bootloader using a liveCD, this is a fairly complicated process. I much prefer having completely separate installations of the two operating systems.

In order to achieve this I decided to build a hardware solution for switching between OS’s. The idea here is that I will use two separate hard drives and physically choose which of the two receives power, thereby only allowing one hard drive at a time to boot on startup. This is easily accomplished using two pieces of hardware:

  1. 4PDT toggle switch
  2. SATA power cable splitter

SATA_SwitchThe switch I chose is not a normal toggle switch. This model features a locking lever which helps to prevent inadvertently switching power to or from the hard drives. This is necessary since accidentally flipping the switch while the computer is running would crash the OS similar to unplugging the system from the wall. The locking lever works by using a spring loaded plunger with a pointy tip mounted on the lever. When in either ON position the tip fits into a notch on the switch body which prevents it from moving. In order to flip the switch you must pull out on the plunger which raises the tip out of the notch, thereby allowing the lever to be moved to the other ON position.

SATA_Harness1SATA1As you can see from the photos I cut the splitter cable in to 3 pieces: (1) power socket which plugs into my PC’s power supply & (2) right angle plugs that will attach to my hard drives. Normally a SATA hard drive power cable has 5 conductors: (1) 12V line, (1) 5V line, (1) 3.3V line & (2) grounds. The orange 3.3V line is rarely used and consequently removed it from the connectors, leaving me with 4 conductors each that needed to be wired to the switch. I added extensions using 22AWG wire so that the plugs could reach from the switch (mounted on the front panel) to the hard drive bays. The front panel of my PC case is made of aluminum, including the removable drive bay covers. This provided me with a fairly sturdy mount for my switch. I simply drilled a 1/4″ hole in the empty 3 1/2″ floppy drive bay cover and mounted the switch. After plugging in the power socket and hard drive plugs I reassembled my PC and tested my dual-boot setup.

SATA2SATA_Harness2This is a really simple and robust way to dual-boot a PC in my opinion since you essentially have two independent PCs using the same hardware. The only disadvantage this has versus a software dual-boot system is that I cannot access the same data from either OS since they are on separate hard drives. For me this is a minor issue since I use my HTPC as a data server which is equally accessible regardless of which OS I choose to run. I’m very pleased with this setup and it’s definitely worth the $17 in parts and about an hour of time I put into it.

6 thoughts on “Dual-Boot PC w/ Toggle Switch”

  1. Just did this for my hackintosh/win7 hybrid. I didn't like having both drives mounted at the same time. Worked perfectly. Thanks 🙂

  2. You can do essentially the same thing with two eide drives. Put a 4 pole switch on the power cable to the drive on the primary connector on the ribbon cable, and set the bios to boot on the primary drive, then the secondary drive. With the switch turned on, you will boot to the primary drive, with the switch off, you will boot to the secondary. Both drives must be set to cable select.

  3. AJ

    I’m sorry, I was confused about what you were asking. You are correct saying that the power connector originally had 5 pairs of wires (10 total) which connected to the right angle plugs. I cut 6 of them short because the switch is handling the power splitting and you don’t need any of the orange wires. This leaves you with one set of 4 wires (12V, 5V, & 2 grounds) for connection to the switch. I hope this clears things up.

  4. Joe, the SATA II Y cables’ power connector plug when it’s cut from the 2 right angle plugs only had 5 wires coming out of it and not 10? The photo of the SATA II Y cable from newegg.com seems to indicate that the power connector plug has 10 wires coming out of it; 5 connected to each of the 2 right angle plugs.

  5. AJ

    Let me clarify since it appears that you are somewhat confused. The SATA power splitter normally provides power from one power jack to 2 sockets for cases where the user does not have enough power connectors for the number of hard drives. What I have done is cut this power splitter into 3 parts: one power jack (which plugs into the computer’s power supply) and 2 power sockets (that plug into the hard drives). As I stated in my tutorial the orange wire can be removed from ALL of the connectors. In the photo I showed one with and one without an orange wire simply to show an example of a before and after. I then wired the power jack as shown into the common poles of the toggle switch. The two sockets were then wired into their own separate poles of the toggle switch. Each connector only has 5 wires, so after removing the orange wires I was left with 4 per connector, which allowed me to use a 4 pole switch (1 wire per pole). I can draw you a schematic if this is still confusing. I did not use crimp-on wire connectors for the extension wires, instead I soldered the connections and used black heat-shrink tubing to cover the exposed wire. Let me know if you have any more questions.

  6. Thanks for the great tutorial! This dual-boot PC w/Toggle Switch cable should be a manufactured product available for purchase at NewEgg.com or Frys.com. I remember mention of a dual-boot toggle switch setup on Screen Savers from TechTV a few years ago and I was inspired recently to create one myself and that’s how I found your website and this tutorial. The SATA cable power socket plug had 10 wires connected to it but it appears you’ve cut off 5 from one half of the plug and the orange wire from the other half; am I correct? And with the wires cut off one half of the plug both right angle HD plugs can still receive power through them? Where did you get those black wire connectors and are they flexible? I’m used to purchasing hard plastic wire connectors and for 22AWG wires the color of the connectors I’ve purchase in the past are a red color.

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