Re: Why dosemu can not access internal harddisks while running from latest GRML in live CD mode?

[Ivan Baldo <ibaldo@adinet.com.uy>]

     Hello.
     The problem with virtualization is that screen readers can't read 
their screens (I guess).
     Using DOSEmu in terminal mode allows screen readers to read the 
screen of the program that it is running and there are recovery programs 
for DOS it seems.
     So, if no virtual machine system allows to use a screen reader then 
it is not useful for Janusz.
     Does anybody know if there is a virtual machine emulator that has 
support for screen reading (support for visually impaired people) and 
raw access to a hard disk?
     Janusz, isn't there any useful recovery program for Linux that you 
can use?
     Here is a list of programs from my Debian Testing distribution:
         - chntpw: NT SAM password recovery utility.
         - gddrescue: the GNU data recovery tool.
         - gzrt: gzip recovery toolkit.
         - safecopy: Copy utility ignoring errors.
         - scalpel: A Frugal, High Performance File Carver.
         - scrounge-ntfs: Data recovery program for NTFS filesystems.
         - scrub: writes patterns on magnetic media to thwart data recovery.
         - testdisk: Partition scanner and disk recovery tool.
         - convmv: filename encoding conversion tool.
         - dosfstools: utilities for making and checking MS-DOS FAT 
filesystems.
         - e2undel: Undelete utility for the ext2 file system.
         - ext3grep: Tool to help recover deleted files on ext3 filesystems.
         - gcp: Advanced command line file copy system.
         - ntfs-3g: read/write NTFS driver for FUSE.
         - recover: Undelete files on ext2 partitions.
         - recoverjpeg: tool to recover JPEG images from a filesystem image.
         - smartmontools: is to control the S.M.A.R.T. capability of 
hard disks.
     All those programs have terminal interfaces.
     You can read more about them searching on Google or in 
http://packages.debian.org/ .
     Hope this helps!!!
     Bye.



El 16/10/11 18:29, Paul Crawford escribió:
> Dear Janusz,
>> I do not know, how to simulate The boot from The bootable CD or DVD from
>> running Dosemu, i did not understand The command sintax for this 
>> operation.
>> Next isue is, if i will be able to emulate booting from boot media
>> successfully, if i will not lost The opportunity to use Speakup screen
>
> I don't think dosemu is the sort of tool that is best suited to 
> testing or analysing the boot process of a CD/DVD for operating system 
> recovery.
>
> dosemu does not emulate every feature of a DOS PC, only the ones 
> needed so far to run certain DOS programs. As far as I understand it, 
> dosemu currently only emulates DMA as used in the sound cards, and not 
> as a full PC behaves. If you were to enable direct hard disk access 
> and try an operating system it would probably fail as it attempted to 
> switch from PIO mode to DMA mode for disk I/O.
>
> I think you should be looking at a 'virtual machine' such as VMware 
> (which I have used to run DOS 6.22 and Windows 95 for testing), or one 
> of the others such as Zen, VirtualBox, etc:
>
> https://help.ubuntu.com/community/VirtualMachines
>
> I don't know how easy it would be to make a 'live CD' with one package 
> installed and configured, so I would suggest installing a Linux 
> distribution on a suitable PC, maybe with a new large HDD (couple of 
> times the HDD you want to emulate) and plenty of memory (say 512MB 
> plus the expected memory for the tested operating system), then 
> installing something like VMware player (which is free, but not open 
> source) and then trying to create a new blank machine and boot your 
> CD/DVD and see if it will restore the 'virtual disk' as you want it to.
>
> The advantage of such an approach is you can simply delete the virtual 
> drive and create a new on in minutes, and you can (with some versions) 
> create snapshots of the system before installing patches, new 
> software, etc, or just to mount them to see what the HDD looked like 
> at that point in time.
>
> dosemu is really only for running DOS software that is reasonably well 
> behaved. If you do use it for direct hardware access (which we do) 
> then it really works best/most reliably for non-operating system 
> components such as special peripherals.
>
> Regards,
> Paul

-- 
Ivan Baldo - ibaldo@adinet.com.uy - http://ibaldo.codigolibre.net/
 From Montevideo, Uruguay, at the south of South America.
Freelance programmer and GNU/Linux system administrator, hire me!
Alternatives: ibaldo@codigolibre.net - http://go.to/ibaldo

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