Is it possible to boot a guest from usb?

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abk4523
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Is it possible to boot a guest from usb?

Post by abk4523 » Thu 20 Jun, 2019 8:59 pm

This is probably just my misunderstanding of the hardware. I have an atapi drive from an old laptop and am trying to use it with PCem. I use an atapi ide to usb adaptor to connect it to my laptop. I tried a pentium overdrive mmx 200 bios and looked for a boot from usb option but could not find one. So I set the bios to look for the boot files on the cd rom drive and booted. I got a "boot from atapi cdrom" message and the machine seems to hang. I know some bioses, as early as 486dx2s, can boot from usb. Does PCem support this feature, am I using the wrong equipment, or am I dreaming something like this can work? I could test with another bios but if PCem does not support this, why bother.

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ppgrainbow
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Re: Is it possible to boot a guest from usb?

Post by ppgrainbow » Thu 20 Jun, 2019 9:09 pm

PCem has no support for USB devices at this time. You can only boot from ATAPI or SCSI CD-ROM or Iomega ZIP drives.

If you want to boot a guest OS from USB, you can place the hard disk image, CD-ROM ISO or Iomega ZIP onto a USB device and boot it from there.

abk4523
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Re: Is it possible to boot a guest from usb?

Post by abk4523 » Thu 20 Jun, 2019 10:34 pm

Thanks for the quick reply. I have a few ideas.

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leilei
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Re: Is it possible to boot a guest from usb?

Post by leilei » Fri 21 Jun, 2019 3:29 am

abk4523 wrote:
Thu 20 Jun, 2019 8:59 pm
I know some bioses, as early as 486dx2s, can boot from usb.
The earliest BIOS USB booting i've seen were chipsets for Pentium 4 systems.... Are you sure you're not confusing with a floppy-based bootloader? USB wasn't a thing at all in the 486 era implied. CD booting wasn't yet a thing either.

abk4523
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Re: Is it possible to boot a guest from usb?

Post by abk4523 » Fri 21 Jun, 2019 11:48 am

I may have misremembered something. I installed Windows Xp on a 486dx2 laptop from cd, but I don't remember if I used a Windows 98 boot disk.

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leilei
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Re: Is it possible to boot a guest from usb?

Post by leilei » Fri 21 Jun, 2019 1:08 pm

abk4523 wrote:
Fri 21 Jun, 2019 11:48 am
I installed Windows Xp on a 486dx2 laptop from cd
XP will refuse to install and run on anything less than a Pentium.

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ppgrainbow
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Re: Is it possible to boot a guest from usb?

Post by ppgrainbow » Fri 21 Jun, 2019 1:49 pm

abk4523 wrote:
Fri 21 Jun, 2019 11:48 am
I may have misremembered something. I installed Windows Xp on a 486dx2 laptop from cd, but I don't remember if I used a Windows 98 boot disk.
Windows XP is not compatible with processors older than a Pentium processor, because it hard requires CMPXCHG8B and CPUID instructions.

abk4523
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Re: Is it possible to boot a guest from usb?

Post by abk4523 » Fri 21 Jun, 2019 4:02 pm

I know. It worked pretty well for a while but the laptop eventually started locking up after logging in.

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ppgrainbow
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Re: Is it possible to boot a guest from usb?

Post by ppgrainbow » Fri 21 Jun, 2019 4:09 pm

abk4523 wrote:
Fri 21 Jun, 2019 4:02 pm
I know. It worked pretty well for a while but the laptop eventually started locking up after logging in.
It would only work if the processor was at least a Pentium Overdrive. :p

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leilei
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Re: Is it possible to boot a guest from usb?

Post by leilei » Fri 21 Jun, 2019 9:36 pm

abk4523 wrote:
Fri 21 Jun, 2019 4:02 pm
I know. It worked pretty well for a while but the laptop eventually started locking up after logging in.
The behavior would be XP throwing a trap exception before the boot splash could even show up.

abk4523
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Re: Is it possible to boot a guest from usb?

Post by abk4523 » Sat 22 Jun, 2019 6:07 pm

My mistake. It was a Pentium II board though I am not sure what chip it used.

nerd73
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Re: Is it possible to boot a guest from usb?

Post by nerd73 » Sat 21 Dec, 2019 10:16 pm

leilei wrote:
Fri 21 Jun, 2019 9:36 pm
abk4523 wrote:
Fri 21 Jun, 2019 4:02 pm
I know. It worked pretty well for a while but the laptop eventually started locking up after logging in.
The behavior would be XP throwing a trap exception before the boot splash could even show up.
It doesn't even do that. It just hard-locks at a blank screen. (at least on the emulated 486)

Xanarki
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Re: Is it possible to boot a guest from usb?

Post by Xanarki » Fri 27 Dec, 2019 6:02 pm

Referring to an earlier post...I wanted to buy an external USB ZIP drive online. I have some ZIP discs that I haven't been able to access in almost 15 years.

If it doesn't work with my Win10, is it somehow possible to make it work via PCEM, just in case? I'm just trying to prepare myself.

Cheez
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Re: Is it possible to boot a guest from usb?

Post by Cheez » Fri 27 Dec, 2019 10:05 pm

I think it wouldn't be connected to the emulated machine. You might have to do a bit of research but I think a VM might possibly be able to do that?

Xanarki
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Re: Is it possible to boot a guest from usb?

Post by Xanarki » Fri 27 Dec, 2019 10:43 pm

Yeah I've never used another external device with PCEM so I'm clueless

Zup
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Re: Is it possible to boot a guest from usb?

Post by Zup » Sat 28 Dec, 2019 9:27 am

abk4523 wrote:
Thu 20 Jun, 2019 8:59 pm
This is probably just my misunderstanding of the hardware. I have an atapi drive from an old laptop and am trying to use it with PCem. I use an atapi ide to usb adaptor to connect it to my laptop. I tried a pentium overdrive mmx 200 bios and looked for a boot from usb option but could not find one. So I set the bios to look for the boot files on the cd rom drive and booted. I got a "boot from atapi cdrom" message and the machine seems to hang. I know some bioses, as early as 486dx2s, can boot from usb. Does PCem support this feature, am I using the wrong equipment, or am I dreaming something like this can work? I could test with another bios but if PCem does not support this, why bother.
I guess that you can try to do it on Linux, but I don't think that would be a good practice.

In linux, you could try to make a new configuration and then edit the config file to use a device as a hard disk image. You'll need to find which device is your USB (i.e.: /dev/sdc) and then edit the line that says hdc_fn = ... so it says hdc_fn = /dev/sdc (note that you should edit the lines hdc_sectors, hdc_heads and hdc_cylinders so they are consistent with your USB device and the BIOS data must match those values).

I think I did it once, but I'd need to test it again to see if it works. Also, keep in mind that most BIOS and OSs supported by PCem have size limitations... maybe your 486 won't be able to boot from a 4Gb SD card.
Xanarki wrote:
Fri 27 Dec, 2019 6:02 pm
Referring to an earlier post...I wanted to buy an external USB ZIP drive online. I have some ZIP discs that I haven't been able to access in almost 15 years.

If it doesn't work with my Win10, is it somehow possible to make it work via PCEM, just in case? I'm just trying to prepare myself.
If your ZIP disk has a valid partition table and ZIP devices are supported on Linux (I guess they are), you could do that trick and access directly as if they were normal hard disks.

But in that case, I'd try to make an image from the disks (using dd or ddrescue, depending on how readablñe are those disks) and then use the image files on PCem.
Cheez wrote:
Fri 27 Dec, 2019 10:05 pm
I think it wouldn't be connected to the emulated machine. You might have to do a bit of research but I think a VM might possibly be able to do that?
That's another option, but the VM must allow USB passthrough on your host and emulated OS. VirtualBox can do it, but it has some problems with Windows hosts and AMD chipsets :( (no problems with Linux hosts). I think that VMWare can do it, even the free version.

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