Last modified: 2023-05-28 08:44
Only the kernel and the default COMMAND.COM were examined, and only as far as could be determined from processing a typical CONFIG.SYS and AUTOEXEC.BAT configuration followed by Universal Standard Protected Mode Operability Test D [1]. A broad evaluation of the effects of the different candidates on the operability and stability of popular applications was not done.
Each candidate was installed onto the same hard disk partition on the same PC with the same BIOS setup, with either FORMAT /S C: or FORMAT C: followed by SYS C: from a prepared boot floppy.
The following driver versions were loaded where applicable:
The following MSDOS.SYS file was installed: [2]
[Options] SystemReg=0 DisableLog=1 Logo=0
Unwanted drivers that MS-DOS might autoload were purged from the disk. (C.f. The Windows 98 Config.txt file about DOS=AUTO and Contents of the Windows Msdos.sys File about DBLSpace and DRVSpace.)
| Windows 98 SE * | Windows ME ** | FreeDOS |
|---|---|---|
| alias MS-DOS 7.1 | alias MS-DOS 8.0 | is free |
Windows 98 [Version 4.10.2222] Revision A DOS is in HMA |
Windows Millennium [Version 4.90.3000] Revision A DOS is in HMA |
FreeCom version 0.84-pre2 XMS_Swap [Aug 28 2006 00:29:00] DOS version 7.10 FreeDOS kernel 2041 (build 2041 OEM:0xfd) [compiled Feb 7 2012] |
| 222390 1999-04-23 22:22 IO.SYS | 116736 2005-04-18 17:54 IO.SYS | 45494 2012-02-07 13:52 KERNEL.SYS |
* Patch KB311561 (MS-DOS Does Not Properly Process Hard Disk Hardware Errors) was not applied. The patched kernel issues the same version string, but its size and date are [222670 2001-12-01 08:37 IO.SYS].
** Unsupported mod based on a boot floppy version of the kernel [3]. Before modding, the binary was different from the one included in KB311561, had the same size but was dated later. ???
For each candidate, a baseline CONFIG.SYS and AUTOEXEC.BAT were tweaked as needed to achieve the following to the extent reasonable:
Extraneous details have been omitted for brevity.
| Windows 98 SE | Windows ME | FreeDOS |
|---|---|---|
DEVICE=C:\LOCAL\UMBPCI\UMBPCI.SYS DEVICE=C:\LOCAL\UIDE\XMGR.SYS /W DEVICEHIGH=C:\LOCAL\UIDE\UIDE.SYS /S1024 /H DOS=HIGH,UMB,AUTO SHELL=C:\COMMAND.COM C:\ /E:2048 /P BUFFERSHIGH=30 FCBSHIGH=4 FILESHIGH=40 STACKSHIGH=9,256 LASTDRIVEHIGH=E |
DEVICE=C:\LOCAL\JEMM\MOVEXBDA.EXE DEVICE=C:\LOCAL\UMBPCI\UMBPCI.SYS DEVICEHIGH=C:\LOCAL\UIDE\UIDE.SYS /S1024 /H DOS=HIGH,UMB,AUTO SHELL=C:\COMMAND.COM C:\ /E:2048 /P BUFFERSHIGH=30 FCBSHIGH=4 FILESHIGH=40 STACKSHIGH=9,256 LASTDRIVEHIGH=E |
DEVICE=C:\LOCAL\UMBPCI\UMBPCI.SYS DEVICE=C:\LOCAL\UIDE\XMGR.SYS /W DEVICEHIGH=C:\LOCAL\UIDE\UIDE.SYS /S1024 /H DOS=HIGH,UMB SHELLHIGH=C:\COMMAND.COM C:\ /E:2048 /P BUFFERSHIGH=30 FILESHIGH=40 STACKSHIGH=9,256 LASTDRIVEHIGH=E IDLEHALT=1 SWITCHES=/E:1024 |
| Basis for comparison. The EBDA is relocated by default. DOS=AUTO is needed to move DRIVEDATA to the UMA. | Microsoft's XMM is
integral to the kernel and is always loaded, even with DOS=NOAUTO. SWITCHES=/E:1024 has no effect. MOVEXBDA fails silently if it is loaded high. DOS=AUTO is needed to move DRIVEDATA to the UMA. | DOS=[NO]AUTO is
unsupported. SHELLHIGH is added. FCBSHIGH is unsupported because FCBs are emulated from file handles (FILES). IDLEHALT is FreeDOS-specific. |
| Windows 98 SE | Windows ME | FreeDOS |
|---|---|---|
LH C:\LOCAL\BIN\FDAPM.COM APMDOS LH C:\LOCAL\BIN\SHSUCDX.COM /C /D:UDVD1 LH C:\LOCAL\DOSLFN\DOSLFNMS.COM LH C:\LOCAL\UIDE\RDISK.COM /S1024 /:E LH C:\LOCAL\BIN\CTMOUSE.EXE |
LH C:\LOCAL\BIN\FDAPM.COM APMDOS LH C:\LOCAL\BIN\SHSUCDX.COM /C /D:UDVD1 LH C:\LOCAL\DOSLFN\DOSLFNMS.COM LH C:\LOCAL\UIDE\RDISK.COM /S1024 /:E LH C:\LOCAL\BIN\CTMOUSE.EXE |
LH C:\LOCAL\BIN\SHSUCDX.COM /C /D:UDVD1 LH C:\LOCAL\DOSLFN\DOSLFNMS.COM LH C:\LOCAL\UIDE\RDISK.COM /S1024 /:E LH C:\LOCAL\BIN\CTMOUSE.EXE |
| Basis for comparison. | No change. | FDAPM.COM is unnecessary. |
Output from MEM (v1.11) /DEBUG /A:
| Windows 98 SE | Windows ME | FreeDOS |
|---|---|---|
Conventional Memory Detail:
Segment Total Name Type
------- ---------------- ------------ -------------
0000 1,024 (1K) interrupt vector table
0040 768 (1K) BIOS data area
0070 6,544 (6K) IO system data
NUL system device driver
CON system device driver
AUX system device driver
PRN system device driver
CLOCK$ system device driver
A: - C: system device driver
COM1 system device driver
LPT1 system device driver
LPT2 system device driver
LPT3 system device driver
CONFIG$ system device driver
COM2 system device driver
COM3 system device driver
COM4 system device driver
0209 2,128 (2K) DOS system data
020b 1,024 (1K) EBDA data area
024c 544 (1K) SECTORBUF data area
026f 512 (1K) BUFFERS BUFFERS=30,0
028f 64 (0K) DOS system code
0294 80 (0K) COMMAND data area
029a 240 (0K) MEM environment
02aa 55,248 (54K) MEM program
1028 589,152 (575K) free
Upper Memory Detail:
Segment Total Name Type
------- ---------------- ------------ -------------
a000 199,280 (195K) reserved
d0a7 23,424 (23K) DOS system data
d0a9 912 (1K) UIDE device driver
UDVD1 installed DEVICE=UIDE
d0e3 464 (0K) DRIVEDATA data area
d101 2,080 (2K) FILES FILES=40 (35 in this block)
d184 256 (0K) FCBS data area
d195 16,080 (16K) BUFFERS BUFFERS=30,0
d583 448 (0K) LASTDRV LASTDRIVE=E
d5a0 3,072 (3K) STACKS STACKS=9,256
d660 5,712 (6K) COMMAND program
d7c6 64 (0K) free
d7cb 3,088 (3K) COMMAND environment
d88d 192 (0K) free
d89a 912 (1K) FDAPM program
d8d4 6,208 (6K) SHSUCDX program
da59 11,648 (11K) DOSLFNMS program
dd32 752 (1K) RDISK program
E: installed DEVICE=RDISK
dd62 3,088 (3K) CTMOUSE program
de24 7,600 (7K) free
Memory Type Total Used Free
---------------- -------- -------- --------
Conventional 640K 11K 629K
Upper 61K 53K 8K
Reserved 323K 323K 0K
Extended (XMS) 3,467,520K 2,097,941K 1,369,579K
---------------- -------- -------- --------
Total memory 3,468,544K 2,098,328K 1,370,216K
Total under 1 MB 701K 64K 637K
Memory accessible using Int 15h 0K ( 0 bytes)
Largest executable program size 629K (644,416 bytes)
Largest free upper memory block 7K ( 7,616 bytes)
Available space in High Memory Area 6K ( 6,128 bytes)
Windows is resident in the high memory area.
|
Conventional Memory Detail:
Segment Total Name Type
------- ---------------- ------------ -------------
0000 1,024 (1K) interrupt vector table
0040 768 (1K) BIOS data area
0070 10,512 (10K) IO system data
NUL system device driver
CON system device driver
AUX system device driver
PRN system device driver
CLOCK$ system device driver
A: - C: system device driver
COM1 system device driver
LPT1 system device driver
LPT2 system device driver
LPT3 system device driver
COM2 system device driver
COM3 system device driver
COM4 system device driver
XMSXXXX0 system device driver
0301 2,416 (2K) DOS system data
0303 1,136 (1K) MOVEXBDA device driver
MOVXBDA# installed DEVICE=MOVEXBDA
034b 160 (0K) UMBPCI device driver
UMBPCIXX installed DEVICE=UMBPCI
0356 544 (1K) SECTORBUF data area
0379 512 (1K) BUFFERS BUFFERS=30,0
0399 64 (0K) DOS system code
039e 80 (0K) COMMAND data area
03a4 256 (0K) MEM environment
03b5 55,248 (54K) MEM program
1133 584,880 (571K) free
Upper Memory Detail:
Segment Total Name Type
------- ---------------- ------------ -------------
a000 196,608 (192K) reserved
d000 23,424 (23K) DOS system data
d002 912 (1K) UIDE device driver
UDVD1 installed DEVICE=UIDE
d03c 464 (0K) DRIVEDATA data area
d05a 2,080 (2K) FILES FILES=40 (35 in this block)
d0dd 256 (0K) FCBS data area
d0ee 16,080 (16K) BUFFERS BUFFERS=30,0
d4dc 448 (0K) LASTDRV LASTDRIVE=E
d4f9 3,072 (3K) STACKS STACKS=9,256
d5b9 5,584 (5K) COMMAND program
d717 64 (0K) free
d71c 3,088 (3K) COMMAND environment
d7de 192 (0K) free
d7eb 912 (1K) FDAPM program
d825 208 (0K) free
d833 6,208 (6K) SHSUCDX program
d9b8 11,648 (11K) DOSLFNMS program
dc91 752 (1K) RDISK program
E: installed DEVICE=RDISK
dcc1 3,088 (3K) CTMOUSE program
dd83 10,176 (10K) free
Memory Type Total Used Free
---------------- -------- -------- --------
Conventional 640K 15K 625K
Upper 64K 54K 10K
Reserved 320K 320K 0K
Extended (XMS) 3,467,520K 2,097,941K 1,369,579K
---------------- -------- -------- --------
Total memory 3,468,544K 2,098,330K 1,370,214K
Total under 1 MB 704K 69K 635K
Memory accessible using Int 15h 0K ( 0 bytes)
Largest executable program size 625K (640,144 bytes)
Largest free upper memory block 10K ( 10,192 bytes)
Available space in High Memory Area 5K ( 5,232 bytes)
Windows is resident in the high memory area.
|
Conventional Memory Detail:
Segment Total Name Type
------- ---------------- ------------ -------------
0000 1,024 (1K) interrupt vector table
0040 768 (1K) BIOS data area
0070 8,400 (8K) IO system data
NUL system device driver
CON system device driver
PRN system device driver
AUX system device driver
LPT1 system device driver
LPT2 system device driver
LPT3 system device driver
COM1 system device driver
COM2 system device driver
COM3 system device driver
COM4 system device driver
CLOCK$ system device driver
A: - C: system device driver
027d 1,248 (1K) DOS system data
027f 192 (0K) FILES FILES=40 (3 in this block)
028c 1,024 (1K) EBDA data area
02cc 3,008 (3K) COMMAND program
0389 272 (0K) MEM environment
039b 55,248 (54K) MEM program
1119 585,296 (572K) free
Upper Memory Detail:
Segment Total Name Type
------- ---------------- ------------ -------------
a000 199,280 (195K) reserved
d0a7 9,344 (9K) DOS system data
d0a9 4,624 (5K) UIDE device driver
UDVD1 installed DEVICE=UIDE
d1cb 1,904 (2K) FILES FILES=40 (32 in this block)
d243 448 (0K) LASTDRV LASTDRIVE=E
d260 2,304 (2K) STACKS data area
d2f0 2,048 (2K) COMMAND environment
d371 192 (0K) free
d37e 6,208 (6K) SHSUCDX program
d503 11,648 (11K) DOSLFNMS program
d7dc 752 (1K) RDISK program
E: installed DEVICE=RDISK
d80c 3,088 (3K) CTMOUSE program
d8ce 29,456 (29K) free
Memory Type Total Used Free
---------------- -------- -------- --------
Conventional 640K 14K 626K
Upper 61K 32K 29K
Reserved 323K 323K 0K
Extended (XMS) 3,467,520K 2,098,041K 1,369,479K
---------------- -------- -------- --------
Total memory 3,468,544K 2,098,410K 1,370,134K
Total under 1 MB 701K 46K 655K
Memory accessible using Int 15h 0K ( 0 bytes)
Largest executable program size 626K (640,560 bytes)
Largest free upper memory block 29K ( 29,472 bytes)
Available space in High Memory Area 10K ( 9,927 bytes)
FreeDOS is resident in the high memory area.
|
| Basis for comparison. | XMM overhead moved from UMA to conventional memory. UMBPCI loaded code in conventional memory to "extend HIMEM.SYS." |
COMMAND.COM resident portion moved from UMA to conventional memory. 100 KiB XMS was allocated for shell swapping. BUFFERS moved from UMA to HMA. About 4 KB of UIDE moved from HMA to UMA * FDAPM is unnecessary. Net savings of 18 KiB under 1 MB. |
* This happened because the FreeDOS kernel does not make HMA space available to drivers loaded in CONFIG.SYS. One can work around this limitation using DEVLOAD to load UIDE.SYS in AUTOEXEC.BAT, at which time the HMA is available.
[1] DOS/4GW v1.95 and v1.97 (as used by the original DOOM and DUKE3D executables, respectively) have bugs that cause serious crashes and hangs if large amounts of XMS memory are provided by an XMM working alone like in the test configuration here. The games used in testing had their extenders replaced by the DOS/32A standard stub.
[2] 98SE flashes a splash screen during boot unless Logo=0 is in MSDOS.SYS. ME (as patched) does not flash a splash screen during boot and ignores Logo=1 in MSDOS.SYS.
[3] The official Windows ME kernel does not permit booting in DOS mode. For this test, IO.SYS and COMMAND.COM from an "MS-DOS startup disk" created by Windows XP 32-bit were fixed with the 75 → EB patch. Installation was accomplished with a "deversioned" 98SE SYS.COM.
[4] Relocating the EBDA is necessary if one wants to expand conventional memory into segment A000 using an EMM as is discussed in the JEMM README. It is unhelpful for the configuration used in this test, but it was worthwhile to establish that all three candidates allow it. 98SE relocates the EBDA by default. FreeDOS relocates it only if asked. ME won't relocate it no matter what, but this was worked around using the utility MOVEXBDA that comes with JEMM.
FreeDOS: (1) The implementation of CONFIG.SYS menus is completely different and a vast improvement over that of MS-DOS. (2) At one time, the FreeDOS roadmap said "Tightly integrated protected mode support will begin with version 1.2," but it is yet to happen.
Only 98SE has the CONFIG$ device driver. Wikipedia identifies it in passing as the "real mode PnP manager." Sounds potentially useful for something other than the well-publicized denial of service attacks, but that is as much as I could find on it. (Docs, anybody?)
MS-DOS 6.22 and earlier do not support FAT32.