[Freedos-user] command.com (Freecom) main environment location
Hi List ! I've seemed to notice Command.com locates its master environment block at the top of conventional memory, just under the video (and under a BIOS defined extended bios data aka EBDA, if any). Is this behaviour user-controllable with some switch while loading FreeCOM ? Or otherwise, depending on the global FDConfig ? I could not find a way to change this - which is not a good design decision overall IMHO, at least not if it can't be overridden :-( Regards -- Czerno -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev ___ Freedos-user mailing list Freedos-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-user
Re: [Freedos-user] command.com (Freecom) main environment location
That's funny, because I thought that the master environment was controlled by the kernel.sys? Maybe they can add a switch that forces the environment be loaded in upper ram instead of conventional? -Chris Http://digitalatoll.com/ Http://tawhakisoft.com/nxdos.html On Thursday, July 4, 2013, Bertho Grandpied wrote: Hi List ! I've seemed to notice Command.com locates its master environment block at the top of conventional memory, just under the video (and under a BIOS defined extended bios data aka EBDA, if any). Is this behaviour user-controllable with some switch while loading FreeCOM ? Or otherwise, depending on the global FDConfig ? I could not find a way to change this - which is not a good design decision overall IMHO, at least not if it can't be overridden :-( Regards -- Czerno -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev ___ Freedos-user mailing list Freedos-user@lists.sourceforge.net javascript:; https://lists.sourceforge.net/lists/listinfo/freedos-user -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev___ Freedos-user mailing list Freedos-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-user
Re: [Freedos-user] command.com (Freecom) main environment location
That's funny, because I thought that the master environment was controlled by the kernel.sys? obviously not as it's size is controlled by '/E:512' Maybe they can add a switch that forces the environment be loaded in upper ram instead of conventional? 'they' could do nearly everything at the time the environment was put to ~9f00:0 there simply didn't exist upper memory in FreeDOS (and having a switch to move ~512 byte to upper memory is not s exiting ;) Tom -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev ___ Freedos-user mailing list Freedos-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-user
Re: [Freedos-user] command.com (Freecom) main environment location
Hi Bertho, I've seemed to notice Command.com locates its master environment block at the top of conventional memory, just under the video (and under a BIOS defined extended bios data aka EBDA, if any). Is this behaviour user-controllable with some switch while loading FreeCOM ? what would be the purpose to change this ? whee would you like to have it ? Or otherwise, depending on the global FDConfig ? I could not find a way to change this - which is not a good design decision why is this not a good design decision ? where would you put it and why ? overall IMHO, at least not if it can't be overridden :-( Tom -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev ___ Freedos-user mailing list Freedos-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-user
Re: [Freedos-user] command.com (Freecom) main environment location
On Thu, 4 Jul 2013 21:08:12 +0200 Tom Ehlert t...@drivesnapshot.de wrote : I've seemed to notice Command.com locates its master environment block at the top of conventional memory Is this behaviour user-controllable with some switch while loading FreeCOM ? what would be the purpose to change this ? whee would you like to have it ? Or otherwise, depending on the global FDConfig ? I could not find a way to change this - which is not a good design decision why is this not a good design decision ? I'm surprised you have to question this! Tis bad because the block in question exceedingly ill-placed, a user who is able, one way or another, to have usable RAM mapped above the 640 k so-called limit into the video memory' segments, up to 736 k (B7FFF), will be forced to use the added memory as UMBs instead of an extension of *contiguous* so-called conventional mem. Of course the default placement of an XBDA (in case there is one, that is, almost always nowadays) deserves the same blame but either the kernel or some utility will routinely relocate it down during Config.sys processing. We could have a separate utility for relocating Freecom's primary env, but, frankly, the command processor shoud be able take care of it itself. where would you put it and why ? The why has been explained. In addition, under /some but not all/ BIOSes, it seems the presence of a DOS MCB-covered zone under the 'video' area may perturb conventional memory reporting by the API of int 15/E820. Not confirmed. Want more ? OK, additionally, some (admittedly very rude, maybe very old) DOS programs will neglect to check where the memory 'above' them ends, and use any and all BIOS int 12 mem without reservation. for that reason the end of the 'transient program area' should as far as possible coincide with the end of conventional (int 12) memory. To where : by default, or absent DOS-managed UMBs, put it on top of the main FreeDCOM code (this is how MS does it). Optionally relocate to an available UMB. overall IMHO, at least not if it can't be overridden :-( Re-iterating ! -- Czerno -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev ___ Freedos-user mailing list Freedos-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-user
Re: [Freedos-user] command.com (Freecom) main environment location
On Thu, Jul 4, 2013 at 4:17 PM, Bertho Grandpied y31415926...@yahoo.fr wrote: On Thu, 4 Jul 2013 21:08:12 +0200 Tom Ehlert t...@drivesnapshot.de wrote : where would you put it and why ? The why has been explained. In addition, under /some but not all/ BIOSes, it seems the presence of a DOS MCB-covered zone under the 'video' area may perturb conventional memory reporting by the API of int 15/E820. Not confirmed. Want more ? OK, additionally, some (admittedly very rude, maybe very old) DOS programs will neglect to check where the memory 'above' them ends, and use any and all BIOS int 12 mem without reservation. for that reason the end of the 'transient program area' should as far as possible coincide with the end of conventional (int 12) memory. Placing the environment at the top of conventional memory is what MS-DOS COMMAND.COM did, and FreeDOS tries to be DOS compatible. I never had a problem because of it. One thing I used to run on my old PC XT clone under MS-DOS 3.3 and 5.0 was a freeware utility form Chris (CED) Dunford. It could map unused video memory in the segment above 640K to DOS conventional memory. With a CGA card you could get 96K of additional RAM. With my Hercules card, I could get 64K. so I booted to a system that had 704K of conventional memory. COMMAND.COM putting the master environment at the top of conventional memory did not cause a problem. While it might be nice to relocate the master environment block elsewhere, like upper memory, it's hardly necessary. People lived without being able to do so for decades without problems. I don't ever recall hearing about the sort of problems you raise as possibilities, and I'd call the chances of them happening rare enough to not be worth worrying about. If you insist on this behavior, feel free to submit a patch that adds it. __ Dennis https://plus.google.com/u/0/105128793974319004519 -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev ___ Freedos-user mailing list Freedos-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-user
Re: [Freedos-user] command.com (Freecom) main environment location
So command.com controller the allocating of dos env ? I still always thought it was a kernel level thing , as the way I coded it in nxbio.sys That reminds me that I need to make a dosenv.asm -Chris Http://digitalatoll.com Http://tawhakisoft.com/nxdos.html On Thursday, July 4, 2013, Tom Ehlert wrote: That's funny, because I thought that the master environment was controlled by the kernel.sys? obviously not as it's size is controlled by '/E:512' Maybe they can add a switch that forces the environment be loaded in upper ram instead of conventional? 'they' could do nearly everything at the time the environment was put to ~9f00:0 there simply didn't exist upper memory in FreeDOS (and having a switch to move ~512 byte to upper memory is not s exiting ;) Tom -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev ___ Freedos-user mailing list Freedos-user@lists.sourceforge.net javascript:; https://lists.sourceforge.net/lists/listinfo/freedos-user -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev___ Freedos-user mailing list Freedos-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-user
Re: [Freedos-user] command.com (Freecom) main environment location
On Thu, Jul 4, 2013 at 5:55 PM, Chris Evans aaxiomfin...@gmail.com wrote: So command.com controller the allocating of dos env ? I still always thought it was a kernel level thing , as the way I coded it in nxbio.sys I misspoke. It's more correct to say that placing it at the top of conventional memory is what MS-DOS did, and where COMMAND.COM expected to see it. Same difference - it's what MS-DOS did, and what FreeDOS does to be compatible. I never saw it cause a problem in MS-DOS, and I don't see it's a problem that needs to be fixed. -Chris __ Dennis https://plus.google.com/u/0/105128793974319004519 -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev ___ Freedos-user mailing list Freedos-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-user
Re: [Freedos-user] command.com (Freecom) main environment location
I just wrote a dosenv.asm for nxbio I'll write it up to a int21 call so user app and resize dos environment at will. On Thursday, July 4, 2013, dmccunney wrote: On Thu, Jul 4, 2013 at 5:55 PM, Chris Evans aaxiomfin...@gmail.comjavascript:; wrote: So command.com controller the allocating of dos env ? I still always thought it was a kernel level thing , as the way I coded it in nxbio.sys I misspoke. It's more correct to say that placing it at the top of conventional memory is what MS-DOS did, and where COMMAND.COM expected to see it. Same difference - it's what MS-DOS did, and what FreeDOS does to be compatible. I never saw it cause a problem in MS-DOS, and I don't see it's a problem that needs to be fixed. -Chris __ Dennis https://plus.google.com/u/0/105128793974319004519 -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev ___ Freedos-user mailing list Freedos-user@lists.sourceforge.net javascript:; https://lists.sourceforge.net/lists/listinfo/freedos-user -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev___ Freedos-user mailing list Freedos-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-user
