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Win95 FAQ Part 12 of 14: MS-DOS Games
Section - 12.1. Why you should run your DOS games in DOS sessions under Windows 95

( Part1 - Part2 - Part3 - Part4 - Part5 - Part6 - Part7 - Part8 - Part9 - Part10 - Part11 - Part12 - Part13 - Part14 - Single Page )
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Top Document: Win95 FAQ Part 12 of 14: MS-DOS Games
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Next Document: 12.2. Quick lesson on PIF files
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   The big speech... here it comes. Skip it if you don't want to read
   about it.
   
   Win95 does all of its hardware control, its network control, its
   drivers, its protocols, whatever, in '386 protected mode, so none of
   its software really needs to run in conventional memory, or in upper
   memory. You get minimum 604 KB free conventional memory, no matter
   what hardware or drivers for Win95 you have loaded.
   
   In addition to this, all of the MS-DOS software interrupts, hardware
   interrupts, function hooks, etc operate in protected mode also. This
   means that DOS programs can still work, even though there aren't any
   DOS drivers handling the hooks. Win95 only provides a basic real mode
   driver set for basic compatibility (HIMEM, SETVER, IFSHLP, COMMAND);
   everything else runs outside of the DOS session. The protected mode
   hooks are re-entrant, so multiple DOS sessions can use them. They are
   also faster in many cases; CD-ROM performance greatly improves, for
   example.
   
   Win95 will also virtualize I/O spaces, if you enable that feature in a
   DOS program's properties. This is similar to what Windows NT does, but
   not as robust. This will prevent the programs from accessing the
   hardware directly. If a "protected" DOS program crashes, it won't take
   the rest of the system with it. "Protection" will, however, add to the
   CPU overhead and may cause a program not to run at all, which is why
   it's an option.
   
   NOTE: Don't confuse this direct hardware access with the DirectX API;
   DirectX programs run in protected Win32 sessions by design, and access
   the hardware through an absolute minimal API. DirectX has nothing to
   do with DOS programs accessing hardware directly.
   
   So, with all this benefit, and not eating any conventional memory and
   still providing a nice compatible DOS box, you should run your DOS
   games in DOS sessions in Win95.
   
   So, hide or delete your CONFIG.SYS, remove all TSRs in AUTOEXEC.BAT,
   get Win95 drivers for all your hardware, and read on.

     * 12.1.1. I only get 540 KB free and I have no CONFIG.SYS or
       AUTOEXEC.BAT. Are you lying to me?
       
   Well, no. It's just when I wrote this thing it was before 4.00.950B
   (OSR2). Apparently, 950B likes to add a few things to MSDOS.SYS: now a
   configuration file instead of program code.
   
   The [options] section of MSDOS.SYS has these and probably many more
   switches that affect conventional memory usage:

[Options]
DoubleBuffer=
Drvspace=
Dblspace=

   These cause extra modules, named DBLBUF and DRVSPACE, to load into
   conventional memory.
   
   DBLBUF is a module that uses conventional memory as a read and write
   buffer for old devices like 8-bit SCSI adapters. If you use IDE or PCI
   SCSI you can remove DBLBUF=1 entirely or set it to zero.
   
   DRVSPACE is the real mode DriveSpace driver, needed to read compressed
   drives in real mode. Normally, this loads as part of the MSDOS module
   so Win95 can unload it when it starts, but this switch loads
   DRVSPACE.SYS explicitly, wether you use compressed drives ir not.
   Removing these lines causes the system to load DRVSPACE.SYS as part of
   MSDOS (as it should) ONLY if compressed drives exist.
   
   To properly edit MSDOS.SYS, go to a DOS prompt and type:

attrib -h -s -r msdos.sys

   You may then edit this file with Notepad or EDIT.COM or whatever.
   

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Top Document: Win95 FAQ Part 12 of 14: MS-DOS Games
Previous Document: News Headers
Next Document: 12.2. Quick lesson on PIF files

Part1 - Part2 - Part3 - Part4 - Part5 - Part6 - Part7 - Part8 - Part9 - Part10 - Part11 - Part12 - Part13 - Part14 - Single Page

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Last Update March 27 2014 @ 02:12 PM