Using External Drives

[Quilica]

I have used external drives only for backup on my Macs. Not for anything else. My question is in way of wanting to expand the use of these devices. Rather than use them solely for back up what and how can they be used to run apps or programs and is it feasible to put apps on them to run straight from those drives. If it works (and I'm making myself clear) to run programs or apps from external drives is there a noticeable lag in response time? I'm not certain that I'm asking all of this correctly so I thought you would fill me in so that I can educate myself on this subject.

 

[ferrarr]

Usually, when you install software or an app, it will install on the Macintosh HD in the Applications folder. I have not tried installing it on another drive, why is this something you want to do? I have always used external drives to hold media like documents, audio, and video files. Sometimes, I would move the downloaded app installer files to the external, but now they are so easy to get online, it's not really necessary.

What Mac and OS are you planning to do this with?

 

[Quilica]

I was considering putting Windows 10 on the external drive using Bootcamp. The reason I asked is due to my getting hairbrained ideas without knowing what the result might be. If I had Windows on the external drive then I could also put the Myst series of games there. It sounds kind of ridiculous to me so I thought I would ask before I got myself two steps out from a cliff face.

 

[krs]

I think running an application on an external drive depends on the specific application - so there is not a general yes/no answer.

I have downloaded the odd application that actually ended up on my main desktop folder (not in the Application folder) and ran fine from there. I'm sure that application would run fine on an external.
And then I also had some apps where the message comes up "Make sure the app is in the Application folder or move it back there, if it is not" - those would probably not run properly on an external.
And then there are all those in between.

My question would be - why would you ever want to do that?

PS: I see you answered the question one minute before I asked.

 

[krs]

I was considering putting Windows 10 on the external drive using Bootcamp. The reason I asked is due to my getting hairbrained ideas without knowing what the result might be. If I had Windows on the external drive then I could also put the Myst series of games there. It sounds kind of ridiculous to me so I thought I would ask before I got myself two steps out from a cliff face.

I don't use bootcamp or Windows on my Mac, but as I understand it, there should be no problem doing what you are suggesting.
When using bootcamp to run Windows, you have to reboot the Mac anyway, so what should work perfectly is to install a basic macOS on the external drive and then when you reboot the Mac via the option key, select the external to boot up on and run Windows 10 in bootcamp on the external.
Sounds like a perfectly legitimate set up to me.

 

[Quilica]

Yeah, well, I'm old enough to know that I am one step away from dumb...always. Oh, the troubles I've seen! All my own doing. Now, I ask before I stick a house key in the electrical socket.

 

[MacInWin]

Quilica, it is generally acceptable to run applications from external drives, but there are at least two caveats to that:

1. The application will be slower than if internally installed. The input/ouput speeds to external drives are not as fast as the bus speeds to the internal drive. Those external drives are, however, catching up and Thunderbolt3 may actually make it a pretty small difference.

2. Some applications will need to have temporary files and customization files that get sprinkled on the drive on which they are installed as well as on the boot drive. And some applications expect to be run from the boot drive, so they are going to be looking for some of there files there.

I tried running my applications from an external drive for a while, but gave up on the exercise as it was more trouble than it was worth.

As for Windows of any flavor, yes, it can be run from an external drive. (Assuming you can get it installed there. I have read that MS is trying to block external installations for piracy reasons.) But it will be dead slow because, again, it will have some files that are on the boot drive that it uses constantly and the I/O to externals is slow unless you are at USB-c or TB3 level speeds. I tried that, too, and gave up on it and now run Win10 in a Parallels virtual machine when I need it.

What you can do, and which works pretty well, is to store your data on an external drive. There will be a bit of a performance hit when the data is read into the application, but after that it works will until you write it back out, when the I/O will again slow things down a bit.

 

[krs]

As for Windows of any flavor, yes, it can be run from an external drive. (Assuming you can get it installed there. I have read that MS is trying to block external installations for piracy reasons.) But it will be dead slow because, again, it will have some files that are on the boot drive that it uses constantly and the I/O to externals is slow unless you are at USB-c or TB3 level speeds. I tried that, too, and gave up on it and now run Win10 in a Parallels virtual machine when I need it.

Would that also be true if Windows is run using bootcamp on an external drive that is booted up with a macOS on that drive the way Quilica plans to do this?
There would be no files on the normal boot drive, only the I/O for the keyboard/mouse/display.

I have run different macOSs on external Firewire and USB 3.0 drives and have not noticed any slowdowns operating this way.
But Windows of course might be different running completely on an external

 

[MacInWin]

@krs, it depends on your interface speed to the external drive. Trying to run any operating system over USB2 was just pig-ugly. USB3 is better, 3.1 even more so. TB made it almost acceptable, TB2 got better. I don't have TB3 drives, so I can't say for them, but from the technology, it should be really pretty good.

I'm no bootcamp expert, but can you use Bootcamp to put Windows on an external drive? I thought it had to be in a partition of the internal drive? In any event, Windows will create cache on the boot drive and the I/O to that cache will be whatever the interface speed is. On the old machine Quilica is talking about, I suspect it's USB2, which will bring in the pig-ugly again. Plus, depending on the application in use, there may be scratch space on the boot drive, which will vary from app to app. Finally, if the memory gets full and swapping starts to happen, that all goes to the boot drive, so even more I/O to contend with.

Firewire 800 and USB3 were sort-of ok, particularly if your boot internal drive was a slow spinner and the external was either a really fast spinner or an SSD. I have four virtual machine images (Win10, Win7, Mojave, and Ubuntu) that run in Parallels. I tried them on external SSD drives with USB3.0 and found that they were just too slow for my taste that way. I moved them to the internal SSD and now they are pretty snappy.

Of course, YMMV.

 

[chscag]

I was considering putting Windows 10 on the external drive using Bootcamp.

Forget that. Neither Apple nor Microsoft support placing Windows on an external hard drive. There are numerous work arounds floating around that you can on your own look into. However, the ones that I saw are complicated and do not always work. Also, each time Windows is updated (which is quite often) you'll need jump thru hoops to get it back working again.

In other words, it's just not worth it.

 

[krs]

@Jake - Maybe I misunderstand something here.
If I install macOS on the external drive and boot from it, doesn't that then become the "boot drive"?
Does macOS even know or care if the drive it has booted from is physically inside the Mac and connected to the processor via an internal bus or in an external enclosure connected via high speed FW or USB?
I didn't think so from my exerience.

@chscag - So Microsoft has taken steps to actually try to prevent installing and running Windows on an external drive. That is good to know, thank-you
I had installed Mojave on an external to try it out and play with it a little bit to see if there are any obvious gotchas before I consider upgrading everyone in the family from ElCapitan to Mojave. Also to test the mod I have for the "Save As..." issue. That all worked fine booting from the external.
I was toying with the idea of installing bootcamp and Windows the same way for the very, very odd occasion where I might need it to test something, but that doesn't now seem to be a good idea.

 

[MacInWin]

@Jake - Maybe I misunderstand something here.
If I install macOS on the external drive and boot from it, doesn't that then become the "boot drive"?

Yes, that is what I said.

Does macOS even know or care if the drive it has booted from is physically inside the Mac and connected to the processor via an internal bus or in an external enclosure connected via high speed FW or USB?

Well, yes and no. The Mac knows that the boot drive is now on the external bus, not the internal bus because that is where the drive is physically attached and where the system has to look for the boot system. At the hardware level, the system knows the difference. But as long as the external drive responds in sufficient time the functions all work, albeit the slower external interface will make the machine seem sluggish in comparison. If the external drive doesn't respond in time the system will kernel panic with the hardware "failure" of the drive being reported. It will do the same kernel panic if the boot drive is the internal drive as well, but the higher speeds of the internal bus give the timing logic more flexibility in drive performance. So a drive that is having issues but is just barely acceptable internally as boot may well fail with a panic if booted in an external enclosure because of the slower interface speeds being added to the marginal response of the drive itself.

I didn't think so from my exerience.

As I said, YMMV. I have actually seen drives that worked internally but would not boot in an external enclosure. I had to put that particular drive back inside and copy from there to the new drive as an external to get the data off of it because it would not boot in the exact same external enclosure to allow it to be cloned to the bare internal. PITA to do the swap twice (actually three times). So bus vs. interface speed can make a difference. With the advent of TB3 and USBc, the differences between internal and external interface speeds is shrinking. But the OP is talking about a very old Mac Pro that probably has original USB and Firewire 400 ports for external interfaces, (I don't know, just speculating) so booting from an external, compared to an internal, is going to be sluggish.

 

[krs]

Thanks, Jake - all very clear and logical.

 

[Kenney]

Have you considered running Win 10 from a Virtual Machine with one of the VM programs? (VirtualBox, VMware, etc.) The only thing that I would think about is the external disk a SSD or "spinning" disk (transfer speeds and are you going to leave it powered up all the time?

KenK

 

[ferrarr]

If you wanted, could you install macSO on the external, then create a Boot Camp partition on that "boot volume"?

 

[krs]

If you wanted, could you install macSO on the external, then create a Boot Camp partition on that "boot volume"?

I suggested that already and it was "shot down"