diskemu

customizer · **Joined:** Wed Jul 23, 2008 4:31 pm **Posts:** 9

I previously had a customized version of UBCD v 3.1. Working well. recently the need came to try to get UBCD to work from a USB key (thumbdrive).
I happened to notice the new util to do that in the newest version. I have it downloaded and is working. heres the thing.
In the old version I had several boot disk images that needed to use diskemu to boot instead of memdisk. I tried to customize with the new version and i dont see diskemu as an option. I only see memdisk. Am i just blind? Is there any hope for these older boot disks?

Icecube · **Joined:** Fri Jan 11, 2008 2:52 pm **Posts:** 1277

No, you are not blind. Only memdisk is available.

Have you tried to add raw or bigraw to the memdisk command?

Quote:

ro Make the simulated disk readonly.
raw Use raw access to protected mode memory.

MEMDISK normally uses the BIOS "INT 15h mover" API to access high memory. This is well-behaved with extended memory managers which load later. Unfortunately it appears that the "DOS boot disk" from WinME/XP intentionally(!) crashes the system when this API is invoked. This command-line option tells MEMDISK to enter protected mode directly, whenever possible. It may, however, break other things.

bigraw Use raw access to protected mode memory, return to big real mode.

(New in 3.08 ) This is like raw, but leaves the CPU in "big real mode" afterwards. This may work for some systems when the raw option doesn't.

http://syslinux.zytor.com/wiki/index.php/MEMDISK

Which images are you trying to boot?

as702 · **Joined:** Tue Jun 17, 2008 3:14 am **Posts:** 276

I'm not too familiar with diskemu, but is it possible to integrate diskemu with the current UBCD distribution alongside memdisk? I remember people having problems with some disk images not booting under memdisk (e.g. quicktech pro).

The idea is allowing users the ability to select between using memdisk or diskemu for booting disk images with. Does isolinux even support this?

Icecube · **Joined:** Fri Jan 11, 2008 2:52 pm **Posts:** 1277

I think you can chainload diskemu from isolinux. If you can give me an image that doesn't work with memdisk, I can try it.

as702 · **Joined:** Tue Jun 17, 2008 3:14 am **Posts:** 276

Icecube wrote:

I think you can chainload diskemu from isolinux. If you can give me an image that doesn't work with memdisk, I can try it.

check your pm.

Icecube · **Joined:** Fri Jan 11, 2008 2:52 pm **Posts:** 1277

as702 wrote:

I'm not too familiar with diskemu, but is it possible to integrate diskemu with the current UBCD distribution alongside memdisk? I remember people having problems with some disk images not booting under memdisk (e.g. quicktech pro).

I also can't boot quicktech pro in memdisk (with raw, bigraw, saveint, emm) or with diskemu. It boots fine when used as floppy image in a virtual machine. I think that quicktech pro overwrites a part of the memory where the driver for the floppy emulation (memdisk an diskemu) resides (not sure).

You can load diskemu as kernel in the isolinux config files.

Code:

LABEL -
MENU LABEL diskemu images
KERNEL /isolinux/diskem1x.bin
APPEND -

See: http://www.nu2.nu/diskemu to download diskemu1x.

Add the necessary text in diskemu.cmd (must be in the root of the cd). If you have different images that you want to boot with diskemu, you have to add the necessary commands in diskemu.cmd.

I successfully booted the freedos image of ubcd with diskem1x (ungzip dosubcd.igz first).

as702 · **Joined:** Tue Jun 17, 2008 3:14 am **Posts:** 276

Thanks.

Icecube · **Joined:** Fri Jan 11, 2008 2:52 pm **Posts:** 1277

@ as702

Open the "Quicktech Pro" image with winimage or Virtual Floppy driver.

You can download a bootable freedos image of 1440 kb from: http://bootcd.narod.ru/images.htm.

Open the "Freedos" image that you have downloaded with WinImage or Virtual Floppy driver.
Copy all files of the "Quicktech Pro" image to the freedos image that you have downloaded (exept for automate.scr ==> if it is on the disk it will run automaticly the burn-in test).

Add a file autoexec.bat to the image:

Code:

@echo off
run qtpro.bat

Or copy the code of qtpro.bat in autoexec.bat

Save the image.

You can also copy the contents of the "Quicktech Pro" image to the /ubcd/dosapps/qte/ folder and execute it from within the ubcd freedos image. I don't know if all test will work correctly it that case.

as702 · **Joined:** Tue Jun 17, 2008 3:14 am **Posts:** 276

I had tried this already for sk8aelf but there were some compatibility issues when using a freedos img (I made a similar one using Caldera DR-DOS 7.05 instead which appears to work fine).

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