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emulating USB-ZIP or USB-FDD


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#1 mr_

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Posted 07 July 2008 - 02:12 PM

I think there is a bit confusion about the term "emulating USB-ZIP" or USB-FDD.

1)

For me "emulating USB-ZIP" means Posted Image (any device, such as this USB-pendrive) claims to be Posted Image (real USB-ZIP).

Or "emulating USB-FDD" means Posted Image (any device, such as this USB-pendrive) claims to be Posted Image (real USB-FDD).

I suspect this real emulating can only be done on hardware / firmware level and is not possible for normal end users. So either you buy a device with this feature or not...
In this case the operating system shouldn't be able to see any difference from the emulated device compared with a real one.

2)

Talking about a USB-pendrives or USB-harddisks now. If I am right I recognized that older BIOS have only option to boot USB-ZIP. Newer BIOS can boot USB-HDD and USB-ZIP and USB-FDD.

On older BIOS USB-ZIP doesn't mean you can not boot up USB-pendrive / USB-harddisk. But you need to fdisking/formatting the device as "USB-ZIP" (this means basically in little words only with no partition table).

Therefore there is an interesting project called makebootfat for multi usb standard booting. It works well but somehow it doesn't work in all cases. Imho this is no "emulating of devices".

On my own comp with a newer BIOS I can only boot a real USB-pendrive / USB-harddisk if fdisking/formatting as USB-HDD (standard way), otherwise it's not booting. It seams for my BIOS:
USB-HDD = Posted Image or Posted Image.
USB-ZIP = Posted Image.
USB-FDD = Posted Image.
The 'new' label's are much more logical to me, aren't them.

3)

What's you opinion on my definitions?

Maybe it's really possible to "emulate" USB-FDD or USB-ZIP on software level with a normal device?

#2 was_jaclaz

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Posted 07 July 2008 - 02:31 PM

Yes, it is possible to emulate ZIP disks.

There are TWO kinds of ZIP disk formatting, see here:
http://www.win.tue.n.../zip/zip-1.html

The USB-ZIP "liked" by most motherboards with this option DO HAVE a partition table, with 4th entry active and geometry of nx64x32.

There is no way AFAIK to emulate floppy disks, but most probably noone ever attempted it seriously, as an emulated floppy disk is 1.44 Mb in size.

There are motherboards (very, very few actually) that allow for "superfloppy" formats.

Apart from makebootfat, there is syslinux:
http://syslinux.zytor.com/usbkey.php

And grub4dos MBR has been reported to work in a very peculiar case:
http://www.boot-land...?showtopic=4863
http://www.boot-land...?showtopic=4830

All the info about pecularities of needed fdisking/formatting can be found in the above two threads and here:
http://www.knoppix.n...ootable_USB_Key
http://wiki.grml.org/doku.php?id=usb

jaclaz

#3 mr_

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Posted 07 July 2008 - 02:52 PM

Interesting but it all sounds basically only like "making it to work with the old USB-ZIP and the new USB-HDD booting standard at the same time". A nice thing anyway, but this is no emulation or did I miss a point?

#4 was_jaclaz

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Posted 07 July 2008 - 03:05 PM

Interesting but it all sounds basically only like "making it to work with the old USB-ZIP and the new USB-HDD booting standard at the same time". A nice thing anyway, but this is no emulation or did I miss a point?


NO, it's me that am missing your point. :)

This is emulation:
http://www.thefreedi...ary.com/emulate

But I am not sure about what you are looking for...:)

...I mean is this aimed to be a "practical" thread or a speculative "philosophical" one?

If the problem is USB booting, the info posted solves the problem in some cases, when not even the above info is useful, one can try using a "kicker" disk or install a "dedicated" bootloader, PLOP has made LOTS of progresses lately:
http://www.plop.at/
http://www.plop.at/en/bootmanager.html
http://www.plop.at/e...mngrusblog.html

:)

jaclaz

#5 mr_

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Posted 07 July 2008 - 04:37 PM

...I mean is this aimed to be a "practical" thread or a speculative "philosophical" one?

To be honest this isn't a theoretical question or word game.

The definition of emulation and virtualization is pretty hard. For example bochs is a computer emulator, while VMware is a virtualizer. Bochs emulates a whole computer, it can emulate hardware which does not exist in reality. VMware is faster and more a manager to abstract different operating systems from each other. If you have not the right CPU in VMware you may not use a few operating systems, because the CPU is virtualized and not emulated (if you want so the guest operating system has some kind of direct access to the CPU and VMware is just abstracting forbidden access).

The software VirtualFloppy emulates as soon as started a real legacy FDD, but it's not a hardware emulation. Only a software emulation with the logical limitation that this device is not bootable. (Yes, there are workarrounds.)

Back to the USB-ZIP / USB-FDD emulation question. A USB-ZIP emulation would be to hardware emulate the real old iomega. With a full emulation you would see in Windows a ZIP drive named iomega.

Otherwise if you use a standard USB pendrive and the "USB-ZIP booting standard" then Windows will detect it as a normal USB pendrive and not as a ZIP. This is more a 'bugfix' because of weak standards (no real standard, USB-HDD booting is now more the defacto standard without real standardization) but the device behaves still like a normal USB pendrive.

That was my point. :)

#6 was_jaclaz

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Posted 08 July 2008 - 09:50 AM

Back to the USB-ZIP / USB-FDD emulation question. A USB-ZIP emulation would be to hardware emulate the real old iomega. With a full emulation you would see in Windows a ZIP drive named iomega.

Otherwise if you use a standard USB pendrive and the "USB-ZIP booting standard" then Windows will detect it as a normal USB pendrive and not as a ZIP. This is more a 'bugfix' because of weak standards (no real standard, USB-HDD booting is now more the defacto standard without real standardization) but the device behaves still like a normal USB pendrive.

That was my point. :)


An USB stick, if formatted as USB ZIP disk, will make possible on some motherboards to boot from it, let's call it "rudimental low-level" emulation.

If you want an USB stick, formatted as USB ZIP disk, to look like a USB ZIP DISK in windows there are "cosmetic" changes you can make:
http://www.virtualpl...ml/icn_drv.html
let's call this "rudimental high-level" emulation

Of course the Vid & Pid of the Device will remain the ones "carved in stone" in the USB stick hardware.

If you want a "more accurate" emulation of a ZIP disk, you can write your own Filter Driver or directly a "USB-stick-driver-that-behaves-like-a-ZIP-disk", this would be "complete high-level" emulation.

In other words, a real mode OS like DOS will treat a USB stick just like the USB ZIP disk, as it has no means to "tell the difference", i.e. like a normal volume, a "protected mode" OS, like Win9x/Me can use a device driver (in this case written "ad hoc") to access the device, on NT based systems, thanks to the HAL, EVERYTHING is "virtual", so you can use a Filter Driver or a Kernel Driver to make the OS think the USB stick is a ZIP disk.

So, I do get your point, but I am still wondering what would be the practical consequences of wasting a few weeks work to build a such a Filter or Kernel driver? :)

jaclaz

#7 mr_

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Posted 08 July 2008 - 11:56 AM

An USB stick, if formatted as USB ZIP disk, will make possible on some motherboards to boot from it, let's call it "rudimental low-level" emulation.

Well, agreed.

If you want an USB stick, formatted as USB ZIP disk, to look like a USB ZIP DISK in windows there are "cosmetic" changes you can make:
http://www.virtualpl...ml/icn_drv.html
let's call this "rudimental high-level" emulation

Agreed.

Of course the Vid & Pid of the Device will remain the ones "carved in stone" in the USB stick hardware.

Yes.

If you want a "more accurate" emulation of a ZIP disk, you can write your own Filter Driver or directly a "USB-stick-driver-that-behaves-like-a-ZIP-disk", this would be "complete high-level" emulation.

Rather "pretty high-level software emulation", works only in Windows.

In other words, a real mode OS like DOS will treat a USB stick just like the USB ZIP disk, as it has no means to "tell the difference", i.e. like a normal volume, a "protected mode" OS, like Win9x/Me can use a device driver (in this case written "ad hoc") to access the device, on NT based systems, thanks to the HAL, EVERYTHING is "virtual", so you can use a Filter Driver or a Kernel Driver to make the OS think the USB stick is a ZIP disk.

Yes, a filter driver is possible but needs very much work, to much for me.

So, I do get your point, but I am still wondering what would be the practical consequences of wasting a few weeks work to build a such a Filter or Kernel driver? :)

Not talking about such a driver but the point of these features in general. You asked me before, now I have more time and just for your curiosity and interest I am glad to tell you about it. :) I hope I remember the most important points I thought about.

USB-pendrive or 2.5" USB-HDD in general:
No external power needed, very small, handy, stable, fast and powerful even in pocket.

USB-HDD booting:
This is a bit messed up for DOS or NT booting. The booted device becomes the grub device hd0,0 and device letter C, while the internal IDE/SATA 0,0 and such devices will be a bit messed up with numbers and letters. In DOS it's a bad idea to load further USB drivers after booting from USB-HDD. On NT like operating systems some applications (harddisk undelete and check) get confused (ok, I doubt it will be different in USB-ZIP mode but unsure).

USB-FDD emulation:
This is best if you have legacy software which wants a floppy drive A:, it's fully bootable (if USB-FDD boot supported) and a 90 % floppy replacement (not just workarround). I like more mature replacement solutions rather then fiddling. Also great for creating bootable disk (dos, backup, virusscan, special purpose, server, recovery...). Very good compatibility.

USB-ZIP emulation:
Also good compatibility and good for a full collection of tools for recovery, special purpose and such. Gives you drive letter A:, therefore no mess with displaced drive letters. With USB-FDD and USB-ZIP you can also load USB drivers in DOS without creating a disaster after booting already from USB because these devices are ignored by the drivers. This seams to be also the best place for a (emergency) bootmanager for multibooting.

USB-CDROM emulation:
Great for 'netbooks' (very small and limited notebooks) without real CD-ROM, you can use it to install operating systems without CD and without CD-ROM in a very easy way. Also nice for portable use (CD autostart is working and readonly). Any special CD's can be also 'burned' onto such a device, also protected mode stuff possible.

The spreading of this features is not very widespread. Very little USB-pendrives support it and currently no known USB-HDD enclosure. Therefore I think I need to live with the known workarrounds, it was worth to ask in the forums for knowledge anyway.

#8 was_jaclaz

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Posted 08 July 2008 - 12:35 PM

USB-HDD booting:
This is a bit messed up for DOS or NT booting. The booted device becomes the grub device hd0,0 and device letter C, while the internal IDE/SATA 0,0 and such devices will be a bit messed up with numbers and letters. In DOS it's a bad idea to load further USB drivers after booting from USB-HDD. On NT like operating systems some applications (harddisk undelete and check) get confused (ok, I doubt it will be different in USB-ZIP mode but unsure).


Maybe one can do some tricks with grub4dos re-mapping of drives...:)

Also, though I never tried it, for DOS, what happens if you boot from USB device to grub4dos, map a floppy image to mem, and before booting it you remove the Active flag of the partition or set partitions as hidden?Drive lettering should not be affected :)

USB-FDD emulation:
This is best if you have legacy software which wants a floppy drive A:, it's fully bootable (if USB-FDD boot supported) and a 90 % floppy replacement (not just workarround). I like more mature replacement solutions rather then fiddling. Also great for creating bootable disk (dos, backup, virusscan, special purpose, server, recovery...). Very good compatibility.


For DOS, you can easily use grub4dos to have a floppy image as fd0, which will get A:\.

For NT based (PE's of any kind) you can use migrate.inf or setupreg.hiv to have a partition as A:\ or B:\, again not perfect, but a working workaround.

USB-CDROM emulation:
Great for 'netbooks' (very small and limited notebooks) without real CD-ROM, you can use it to install operating systems without CD and without CD-ROM in a very easy way. Also nice for portable use (CD autostart is working and readonly). Any special CD's can be also 'burned' onto such a device, also protected mode stuff possible.

About CD-ROM enulation, the matter is different, there EXIST devices working like "double head" CD-ROM and USB stick, besides the U3 concept:
http://www.boot-land...?showtopic=4577

And this Manufacturer:
http://www.udrw.com/en/index.php
http://www.udrw.com/en/tech/index.php

offers them.

:)

jaclaz

#9 mr_

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Posted 08 July 2008 - 01:07 PM

addition about my last posting:

USB-FDD emulation: Might be good for BIOS update without legacy FDD. USB-FDD is legitimate and intended by BIOS update providers (I guess so), bootdisk to bootusb not so much (and beware of software emulated FDD's like memdisk for this purpose).

Maybe one can do some tricks with grub4dos re-mapping of drives...:)

Also, though I never tried it, for DOS, what happens if you boot from USB device to grub4dos, map a floppy image to mem, and before booting it you remove the Active flag of the partition or set partitions as hidden?Drive lettering should not be affected :)

For DOS, you can easily use grub4dos to have a floppy image as fd0, which will get A:\.

I done that. Grub4dos floppy emulation works well as long you do not use some protected mode stuff. Biggest disadvantage of these images is that changes are virtual and not write back to the image and therefore hard to update.

About CD-ROM enulation, the matter is different, there EXIST devices working like "double head" CD-ROM and USB stick, besides the U3 concept:
http://www.boot-land...?showtopic=4577

The CD-ROM of grub4dos emulation works very well for small real mode iso's. For bigger iso's (out of mem) or protected mode stuff (driver has no longer access) it's not working well.

And this Manufacturer:
http://www.udrw.com/en/index.php
http://www.udrw.com/en/tech/index.php

Interesting product.

#10 ibach

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Posted 15 May 2015 - 07:49 PM

Jaclaz... Looking at this old topic I've remembered some of your good answers...

Please look at this one for me if you find time...

 

I did something to my samsung HDD few years ago, when making bootable USB HDD with multiple partitions.
I have erased the drive completely (i did that few times with different software even used boootit to write 000 to it)
When I plug the drive to the computer standard SATA port it is recognised by windows as HDD.
When pluged in USB port, it is not seen as HDD, windows cannot acess the drive at all.
When in SATA port, if I try Runtime Software like get data back on it, it is listed as FD1!!!

I think I have written something to the disk at low level to be able to boot it as big FDD, but that part appears to be hidden too good.
Does anyone renmember what is it i might have used to do that?!
How to get the disk to be normal HDD again?!

 

I have allready posted this sa thread on :

http://www.911cd.net...t=0#entry176242


Edited by ibach, 15 May 2015 - 07:50 PM.


#11 Wonko the Sane

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Posted 16 May 2015 - 09:53 AM

Jaclaz just replied to your post on 911CD. :)

 

:duff:

Wonko






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