RE: Weirdest thing ever

RE: Weirdest thing ever

[Xavier Tarifa]

I'm using what gentoo calls dosemu-1.4.1_pre20091009 . And all other programs seem to work, but the one that needs to invoke dos4g (which is the main program, by the way) does not. Right now this machine is working with a 32-bits 1.4.0.0 version of dosemu, but the 32 bits version has  2 Gb max filesize which we will meet soon and it's gone with the 64 bits version. I tried the 64-bits 1.4.0.0 version but it seems to have problems with file locking.

-----Mensaje original-----
De: solarflow99 [mailto:solarflow99@gmail.com] Enviado el: jueves, 27 de enero de 2011 15:18
Para: Xavier Tarifa
CC: linux-msdos@vger.kernel.org
Asunto: Re: Weirdest thing ever

what version of dosemu?  do other dos programs work ok?  I haven't tried dos4g myself, maybe others on here can comment if it works for them.



On Thu, Jan 27, 2011 at 4:43 AM, Xavier Tarifa <Xavier.Tarifa@adparts.com> wrote:
> Here's the thing:
> I'm using  a 64-bits dosemu. I tested that it could run our programs without problems on a test server running CentOS 5.4. Everything worked fine, so I tried to put it in our production server, running a 64-bits fedora 10. It didn't work. Dosemu hangs when it tries to execute dos4g.exe (it seems that it's a memory extender). Top shows  a processor maxing out on dosemu.
>
> I ran it with strace hoping to see if it entered a loop or something, and to my surprise then the program worked fine. And that's the thing, dosemu works as it should when I run it through strace, but  hangs when it should execute dos4g if I run it "normally". The uids/gids are the same, I've compared the memory maps and they are exactly the same and I don't know what else to compare. Anyone has any idea of why it is doing this, and how to make it work without strace? I know that the obvious thing would be installing the CentOS that's proved to work, but this server is on the other side of the country and I don't have physical access to it. Any ideas are welcomed.
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Re: Weirdest thing ever

[Paul Crawford]

Dear Xavier,
My own limited experience of dosemu has focused on the 32-bit version, 
and I have generally found it to be more compatible than the v64-bit 
version. I have put this down to the native emulation of the vm86 
instruction under 32-bit mode.

You reasoning for wanting 64-bit, that of accessing files of >2GB might 
be flawed as most 32-bit programs, and most 16-bit DOS programs, have 
basic limits of 32-bits for file size & offset operations.

While it is conceivable that a DOS program could read beyond 2GB, it is 
very unlikely it could seek to those positions, and very certain it 
could not do so beyond 4GB.

You may get things working OK in 64-bit dosemu by some minor changes, as 
it seems the dos4g is rather sensitive to this, you may not really get 
what you want in file access.

Finally, have you tried contacting the author of dos4g in case they can 
help with compatibility? Though an old product, they might have some 
interest in helping with dosemu use as you (at the very least) have a 
business interest in porting DOS to a modern OS.

Regards,
Paul

On 27/01/11 14:41, Xavier Tarifa wrote:
> I'm using what gentoo calls dosemu-1.4.1_pre20091009 . And all other
> programs seem to work, but the one that needs to invoke dos4g (which
> is the main program, by the way) does not. Right now this machine is
> working with a 32-bits 1.4.0.0 version of dosemu, but the 32 bits
> version has  2 Gb max filesize which we will meet soon and it's gone
> with the 64 bits version. I tried the 64-bits 1.4.0.0 version but it
> seems to have problems with file locking.

-- 
Dr. Paul S. Crawford
Satellite Station
Dundee University
Small's Wynd, Dundee,
DD1 4HN, U.K.
Tel: +44 (0)1382 38 4687
Email: psc@sat.dundee.ac.uk
The University of Dundee is a Scottish Registered Charity, No. SC015096

Re: Weirdest thing ever

[Paul Crawford]

Dear Xavier,
> While it is conceivable that a DOS program could read beyond 2GB, it is
> very unlikely it could seek to those positions, and very certain it
> could not do so beyond 4GB.

Just to say that in the course of other testing here, I looked to see 
what the Microsoft C6.0 library calls for filelength() did with 64-bit 
dosemu. What I found was:

With 32-bit Linux/dosemu it can't open files >2GB.

With 64-bit it can open files >2GB but sees the length incorrectly:

For <4GB it is correct if you treat the returned value as unsigned. This 
may be the case in some software, but it is unlikely to be universal.

For files >4GB it seems to only get the lower 32-bits of the size, so 
the file appears (incorrectly) to be less than 4GB in size. I would have 
prefered the system to return (4GB-1) as at least you know the file is 
very big in this case!

However, I have not tested to see if useful data access is possible >2GB 
as I don't have any DOS applications that use very large files.

Regards,
Paul
-- 
Dr. Paul S. Crawford
Satellite Station
Dundee University
Small's Wynd, Dundee,
DD1 4HN, U.K.
Tel: +44 (0)1382 38 4687
Email: psc@sat.dundee.ac.uk
The University of Dundee is a Scottish Registered Charity, No. SC015096

RE: Weirdest thing ever

[Xavier Tarifa]

Well I didn't expected it to work beyond 4 Gb. I already tested it and it works with a database file of about 3 Gb, so data access is possible and that's good enough (in 15 years it has grown to almost 2gb and in less than a year we plan to migrate to another solution, so it will do).

Seeing that in the test server it's working without problems with a 64 bits CentOS we've decided delete the fedora installation and install CentOS, so I won't worry looking more into it.

-----Mensaje original-----
De: Paul Crawford [mailto:psc@sat.dundee.ac.uk] 
Enviado el: viernes, 28 de enero de 2011 14:13
Para: Xavier Tarifa
CC: linux-msdos@vger.kernel.org
Asunto: Re: Weirdest thing ever

Dear Xavier,
> While it is conceivable that a DOS program could read beyond 2GB, it 
> is very unlikely it could seek to those positions, and very certain it 
> could not do so beyond 4GB.

Just to say that in the course of other testing here, I looked to see what the Microsoft C6.0 library calls for filelength() did with 64-bit dosemu. What I found was:

With 32-bit Linux/dosemu it can't open files >2GB.

With 64-bit it can open files >2GB but sees the length incorrectly:

For <4GB it is correct if you treat the returned value as unsigned. This may be the case in some software, but it is unlikely to be universal.

For files >4GB it seems to only get the lower 32-bits of the size, so the file appears (incorrectly) to be less than 4GB in size. I would have prefered the system to return (4GB-1) as at least you know the file is very big in this case!

However, I have not tested to see if useful data access is possible >2GB as I don't have any DOS applications that use very large files.

Regards,
Paul
--
Dr. Paul S. Crawford
Satellite Station
Dundee University
Small's Wynd, Dundee,
DD1 4HN, U.K.
Tel: +44 (0)1382 38 4687
Email: psc@sat.dundee.ac.uk
The University of Dundee is a Scottish Registered Charity, No. SC015096

Re: Weirdest thing ever

[solarflow99]

when you go to use centos, try to use the proper package for it or
compile the latest out of SVN.



On Fri, Jan 28, 2011 at 9:35 AM, Xavier Tarifa
<Xavier.Tarifa@adparts.com> wrote:
> Well I didn't expected it to work beyond 4 Gb. I already tested it and it works with a database file of about 3 Gb, so data access is possible and that's good enough (in 15 years it has grown to almost 2gb and in less than a year we plan to migrate to another solution, so it will do).
>
> Seeing that in the test server it's working without problems with a 64 bits CentOS we've decided delete the fedora installation and install CentOS, so I won't worry looking more into it.
>
> -----Mensaje original-----
> De: Paul Crawford [mailto:psc@sat.dundee.ac.uk]
> Enviado el: viernes, 28 de enero de 2011 14:13
> Para: Xavier Tarifa
> CC: linux-msdos@vger.kernel.org
> Asunto: Re: Weirdest thing ever
>
> Dear Xavier,
>> While it is conceivable that a DOS program could read beyond 2GB, it
>> is very unlikely it could seek to those positions, and very certain it
>> could not do so beyond 4GB.
>
> Just to say that in the course of other testing here, I looked to see what the Microsoft C6.0 library calls for filelength() did with 64-bit dosemu. What I found was:
>
> With 32-bit Linux/dosemu it can't open files >2GB.
>
> With 64-bit it can open files >2GB but sees the length incorrectly:
>
> For <4GB it is correct if you treat the returned value as unsigned. This may be the case in some software, but it is unlikely to be universal.
>
> For files >4GB it seems to only get the lower 32-bits of the size, so the file appears (incorrectly) to be less than 4GB in size. I would have prefered the system to return (4GB-1) as at least you know the file is very big in this case!
>
> However, I have not tested to see if useful data access is possible >2GB as I don't have any DOS applications that use very large files.
>
> Regards,
> Paul
> --
> Dr. Paul S. Crawford
> Satellite Station
> Dundee University
> Small's Wynd, Dundee,
> DD1 4HN, U.K.
> Tel: +44 (0)1382 38 4687
> Email: psc@sat.dundee.ac.uk
> The University of Dundee is a Scottish Registered Charity, No. SC015096
> --
> To unsubscribe from this list: send the line "unsubscribe linux-msdos" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>
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Re: Weirdest thing ever

[solarflow99]

what version of dosemu?  do other dos programs work ok?  I haven't
tried dos4g myself, maybe others on here can comment if it works for
them.



On Thu, Jan 27, 2011 at 4:43 AM, Xavier Tarifa
<Xavier.Tarifa@adparts.com> wrote:
> Here's the thing:
> I'm using  a 64-bits dosemu. I tested that it could run our programs without problems on a test server running CentOS 5.4. Everything worked fine, so I tried to put it in our production server, running a 64-bits fedora 10. It didn't work. Dosemu hangs when it tries to execute dos4g.exe (it seems that it's a memory extender). Top shows  a processor maxing out on dosemu.
>
> I ran it with strace hoping to see if it entered a loop or something, and to my surprise then the program worked fine. And that's the thing, dosemu works as it should when I run it through strace, but  hangs when it should execute dos4g if I run it "normally". The uids/gids are the same, I've compared the memory maps and they are exactly the same and I don't know what else to compare. Anyone has any idea of why it is doing this, and how to make it work without strace? I know that the obvious thing would be installing the CentOS that's proved to work, but this server is on the other side of the country and I don't have physical access to it. Any ideas are welcomed.
> --
> To unsubscribe from this list: send the line "unsubscribe linux-msdos" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>
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Weirdest thing ever

[Xavier Tarifa]

Here's the thing: 
I'm using  a 64-bits dosemu. I tested that it could run our programs without problems on a test server running CentOS 5.4. Everything worked fine, so I tried to put it in our production server, running a 64-bits fedora 10. It didn't work. Dosemu hangs when it tries to execute dos4g.exe (it seems that it's a memory extender). Top shows  a processor maxing out on dosemu. 

I ran it with strace hoping to see if it entered a loop or something, and to my surprise then the program worked fine. And that's the thing, dosemu works as it should when I run it through strace, but  hangs when it should execute dos4g if I run it "normally". The uids/gids are the same, I've compared the memory maps and they are exactly the same and I don't know what else to compare. Anyone has any idea of why it is doing this, and how to make it work without strace? I know that the obvious thing would be installing the CentOS that's proved to work, but this server is on the other side of the country and I don't have physical access to it. Any ideas are welcomed.
--
To unsubscribe from this list: send the line "unsubscribe linux-msdos" in
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