how to add a 2nd virtual hard disk ?

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Kieutrang
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Joined: 3. Sep 2019, 11:56

how to add a 2nd virtual hard disk ?

Post by Kieutrang »

Hello
I am on windows 7 and use Virt.Box (last version) to emulate DOS 6.22 or Windows 3.11
I do not know how to add a 2nd virtual hard disk.
Is there anyone who could help me ?
and thank you in advance.
mpack
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Re: how to add a 2nd virtual hard disk ?

Post by mpack »

Go to VM settings | Storage panel. See the button indicated in the picture when the IDE controller is selected.
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Be aware that an IDE controller can have a maximum of four drives attached (two channels, two drives on each channel). Typically one of those is a CD, another is the boot hard drive. That leaves you with two empty slots. DOS and Win3.1 don't support SATA.

On a physical PC you would only have had one extra drive slot in practice, because the speed on each channel is set by the slowest drive, and you don't want a hard drive to be limited to the speed of a CD. However VirtualBox doesn't simulate that limitation.
socratis
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Re: how to add a 2nd virtual hard disk ?

Post by socratis »

mpack wrote:because the speed on each channel is set by the slowest drive
Oh, I wasn't aware of that! Not that the HDs of the day were speed daemons, but still...
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mpack
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Re: how to add a 2nd virtual hard disk ?

Post by mpack »

socratis wrote: Oh, I wasn't aware of that! Not that the HDs of the day were speed daemons, but still...
It's a common feature of multidrop buses: a slow device might interpret a garbled high speed communication as an instruction to grab the bus and send data, with disasterous consequences.

But, your comment got me to research modern protocols. E.g. Q: Does SATA support multidrop? A: Apparantly not, each channel is physically separated. Q: We know that USB is usually point to point, but what if you have a mix of USB2 and USB3 devices connected to a USB3 hub, are they all reduced to USB2 speeds? A: again there seems to be physical separation between the USB2 bus and the USB3 bus, so USB2 devices will not see high speed USB3 traffic. Q: What multidrop protocols are still in widespread use? A: Well there's Ethernet, though the modern norm is to cable it point to point. There are chip level protocols such as I2C, but usually the designer will try to have all I2C devices on the PCB rated for the same high speed.
socratis
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Re: how to add a 2nd virtual hard disk ?

Post by socratis »

Thanks Don for the research... ;)

The only one that I know that it used to lower USB speeds was if you mixed USB1 with USB2 in the same USB2 hub. If you're using a USB3 hub for example, no such issue exists between USB2 and USB3, and I've actually seen it in practice...
Do NOT send me Personal Messages (PMs) for troubleshooting, they are simply deleted.
Do NOT reply with the "QUOTE" button, please use the "POST REPLY", at the bottom of the form.
If you obfuscate any information requested, I will obfuscate my response. These are virtual UUIDs, not real ones.
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