On Wed, Jan 9, 2013 at 11:13 AM, Rugxulo <rugx...@gmail.com> wrote:
> On Wed, Jan 9, 2013 at 3:38 AM, dmccunney <dennis.mccun...@gmail.com> wrote:
>> On Wed, Jan 9, 2013 at 2:32 AM, Michael Robinson
>> <plu...@robinson-west.com> wrote:
>>> A protected mode dos like the one under Windows 9x and Windows ME
>>> could be interesting and would justifiably deserve a different name
>> I wouldn't call that a "protected mode DOS".  Win98/ME used DOS as a
>> real mode loader for Windows.  The protected mode portions were in the
>> Windows code, and once Windows was loaded, DOS was out of the loop.
> I thought WinME removed the real mode bootup, hence lower compatibility?

Don't have it and haven't used it, so don't know.  Everything I've
heard indicates it should have been called Win98 Third Edition. I'm
pretty sure there was still DOS underneath like in ME.  Removing the
real mode loader didn't occur till NT.

> Anyways, sure it preempted various DOS things, but other parts were
> still used behind the scenes. It probably just switched modes a lot
> (similar to DOS extenders). Indeed, I don't think it would run without
> DOS, even if you did manage (somehow) to bootup without it.

Might not, but the question is what DOS actually did under it.  Memory
and process management would all be on the Win side.  DOS might get
involved in file system access, but I'm not sure I see why.  The same
sort of thing could be done native from Windows instead of passed
through DOS.

>>> Gates made some very bad assumptions ... nobody will ever
>>> need more than 640k of memory for executable programs
>>> and drivers...
>> That wasn't a Gates decision, it was an IBM decision.  The 8088 CPU
>> used by the original PC had a one megabyte address space.
> Rumor is that IBM wanted 512 kb limit but MS complained! So we should
> be grateful!  ;-)


> Tim Paterson successfully used the full MB of RAM on his original 8088
> clones. Even MS had some of those machines for a long time so that
> they could "link the[ir] linker".
> Besides, you could still use more (kinda sorta) via EMS. It was many
> years before extended RAM was cheap and common enough for software to
> be useful over 1 MB.

EMS used a 64KB page frame located in the block between 640K and 1MB,
and paged memory above 1MB into it for use.  My old XT clone had an
AST 6Pak card with 1MB EMS.  I used the AST drivers to create a 512KB
RAMdisk and a 256KB disk cache.  AUTOEXEC.BAT loaded a few constantly
used things to the RAMdisk and made the RAMdisk first in the %PATH%,
and things that could be told where to create temp files were pointed
there.  Sped things up a treat.

I also had a freeware utility that could grab up to 96K of unused
video memory above 540K and map that to DOS.  I had 64K available,
because I used a Hercules card, so DOS booting thinking I had 704K.

>> Given that you have a megabyte available, total, and some *will* need
>> to be reserved for the system, where *do* you draw the line?
> Tegra 2 reserved part of its total RAM (address space) for the
> graphics. A lot of other integrated chips / SoCs or whatever do too.

Yeah, but they're all 32 bit processors, which is a whole different thing,

> This is also why XP (32-bit) allegedly can only use 3.1 GB of RAM.

Not just allegedly.  See Mark Russinovitch's explanation of the
underlying issues in his blog series:

On my desktop, I have 4GB RAM, but XP can only use about 3.2MB of it.
I found a freeware RAMdisk driver that can use the RAM XP can't see,
and have a 763MB RAMdisk seen as Z:, with a compressed NTFS file
system.  I do things like run Firefox from it.

> There are always hardcoded limits in everything, it's unavoidable.

The question is where they are.

>>> Actually, there is OS/2 which was supposed to be the competitor to
>>> Windows 9x and I'll bet that IBM is willing to release source code
>>> to it.  Maybe the freedos community should get it's hands on OS/2
>>> and develop it further.
>> If IBM is willing to release code, that's news to me.
> No, they've said at least twice, very openly, that they will never do
> so. Besides, lots of the code is copyrighted by MS still (due to the
> 1.x co-development), so that makes it all the more complicated. IBM
> just suggests people migrate to Linux and/or Java these days.

It would be lovely if they did open source it, but stuff like MS's
participation in the original development would make that difficult.

>> You can still get OS/2 from an outfit called eComstation:
>> http://www.ecomstation.com/product_info.phtml
> Yes, it sells a 5-pack of licenses for [EDIT] $149 USD or such. Not
> sure how well the DOS support still works, but I think it claims to
> have semi-recent Firefox, OpenOffice, Java, etc. Though I would be
> skeptical that it wouldn't boot properly, honestly, but hopefully
> they've fixed most of that in their [EDIT] 2.1 release.

I don't see why DOS support shouldn't still work.  The Firefox port is
third-party - Mozilla officially supports Windows, OS/X and Linux -
but the underlying code was designed to be portable.  For that matter,
I believe there are still people doing VMS ports.

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