Fixing Windows OSR2 bugs (or are they features?)

Fixing Windows OSR2 bugs (or are they features?)

Windows 95B (also known as OEM Service Release 2, or OSR2) remains an anomaly among Windows versions. Windows 95B is arguably the latest flavour of Windows 95, with several minor bug fixes and device drivers. Win95B is somewhat more stable than earlier releases of Win95, and the improved device support is handy. But Win95B also includes a few maddening bugs. Notable among these is OSR2's incapability to dual boot between Win95B and an older version of DOS. You also cannot run Windows 3.x in DOS mode using Win95B. Both of these shortcomings are inconvenient for people who need to test programs in both environments (or who simply need to run an old program with its preferred OS).

These two failings of Win95B are all the more galling because they aren't really accidental bugs. They are bugs that were deliberately introduced into Win95B as "features" to interfere with the use of older software. There should be a word for bugs that are wilfully created as features. Perhaps they are "fugs". In any case, creative programmers around the world have taken up the challenge and fixed both of these failings.

Fixing the missing dual-boot feature of Win95B is a simple matter of change to a 400B boot program. This program resides in the first physical sector of your hard drive and controls the boot-up sequence.

Jorg Weske, in Germany, has created a small program called W95boot.exe that replaces Win95B's crippled dual-boot code with functional code from the original Win95. W95boot.exe also works with Windows NT 3.5 or 4.0, using an NT switch I will describe in a moment.

Weske recommends you run W95 boot.exe from a DOS 6.0 floppy boot disk. It creates a backup of your Win95B boot sector before changing it. If something goes wrong, you can run the command W95boot-R (for restore) and you're back to normal.

For users of NT 3.5 or 4.0 together with OSR2, run the command W95boot-NT.

Instead of modifying the real boot sector, this command modifies Bootsect.dos, the file used by the NT boot loader to enable multiboot capabilities.

To obtain a copy of W95boot.exe, which is freeware, go to html and download the 26KB file Unzip this file into its own separate folder. You must read the documentation file W95boot.doc (a DOS text file contained within the zip file) to learn important exceptions before you proceed.

The incapability of Win95B to run Windows 3.x in DOS mode has been fixed by Ralf Buschmann, another German programmer.

Download Osr2fix.exe -- a 30KB file -- by clicking a link entitled "A simple procedure" about halfway down Buschmann's Web page at Osr2fix.exe also fixes the dual-boot problem and other fugs described on the page.

When using Win95 with Win3.1

Although these patches restore the disabled capabilities, there are still some minor glitches in OSR2 they can't help you with. The following items give you the pointers you need in case you run into these situations.

If you run Windows 3.11 using Win95's DOS 7.0 or Win95B's DOS 7.1, you won't be able to employ 32-bit disk or file access in Windows 3.11. You must fall back on the older 16-bit access to your drives.

This is caused by Win95's reliance on ifshlp.sys, which boots in real mode during startup.

Similarly, you cannot routinely create a permanent swap file in Windows 3.x under DOS 7. (Windows 95 did away with the concept of a "permanent" swap file because it uses a dynamically sized one. But the idea was that a single, contiguous area of your hard disk would provide faster application swapping than a fragmented area.) To set up a permanent swap file, you must run the LOCK command in DOS before starting Windows 3.x. After the swap file is established, you can quit Windows and run the UNLOCK command at a DOS prompt. Your swap file will continue to function (it's permanent until you reconfigure it). You can get information about these two commands by typing "LOCK /? and UNLOCK /?" at a DOS prompt.

A permanent Windows 3.x swap file must be placed on a drive named C: or whatever your "primary partition" is. It can't go on any "extended partition", usually named D: or higher, that was created with OSR2's DOS 7.1.

Finally, OSR2 does not support any version of the "share" capabilities that come with DOS 6.22's SHARE.EXE or Windows 3.x's VSHARE.386. These "share" programs allow two applications to use the same open file. Some applications, including Microsoft Word for Windows 6.0, require some version of "share" or they won't run under Windows 3.x.

Fix for Net download speeds

Developers at Microsoft are changing the forthcoming Windows 98 to improve users' Internet download speeds across modems. Windows 95 uses a Registry setting that can be inefficient for Internet downloads. Specifically, the Registry sets a value called MaxMTU (which stands for Maximum Transmission Unit) to 1500. This is good value for people who access the Net through a LAN, but a poor one for people who use a modem.

To its credit, Microsoft seems to be changing the defaults in Windows 98. Microsoft Windows developer Mike Zintel confirmed that Win98 will default to a more efficient MaxMTU value of 576 if it detects an Internet connection slower than 10Mbps. In other words, Win98 will use a different default if the user is on a LAN (1500) than the default used for a dial-up modem (576). The value 576 is a widely used Internet standard.

Why is this important? Readers who have changed their settings have reported improvements of up to double their former speed. The difference is only noticeable, however, on a relatively lightly loaded server, and then only in some cases.

Finding out why the MTU setting speeds up some downloads is tricky. The behaviour depends on Internet conditions and is thus difficult to reproduce. Microsoft representative Zintel; however, suggests three reasons why MTU might affect throughput.

1. As line errors increase on an Internet connection, a smaller MTU such as 576 makes retransmissions faster than a larger MTU such as 15002. When you are running an asynchronous application such as video across the Internet, a larger MTU can make your system feel less responsive3. Certain servers do not implement the IP's retransmission algorithms well, and benefit from a smaller MTUIf you don't want to wait for the release of Win98 to fix this problem, you can change your Windows 95 defaults now. Because the process of editing the Registry in this case is complex, I recommend you use a utility to handle the changes.

Tweak DUN 1.2 (www, tweakdun), by Patterson Design Systems and NetPro Northwest, changes your dial-up networking settings.

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