About Windows 95 and Multitasking

Q: Can Windows 95 preemptively multitask Win16 applications?

A: No.  Because Win16 applications were written for a cooperative multitasking environment, they cannot handle the stress of being  "preempted" during execution.  Therefore Windows 95 must handle these applications in the same way that Windows 3.1 does: by giving them exclusive control of the CPU for as long as they are executing.  When, and only when, the application makes a specific API call - one of the few such calls that constitute safe points at which Windows can wrest control away from the program - are other programs allowed to execute.  This is "cooperative" multitasking, and has proven to be ineffectual when running more than a handful of programs simultaneously or when running CPU-intensive programs such as communications, print and/or fax programs. BOTTOM LINE:  WINDOWS 95 ADDS LITTLE VALUE FOR THE LARGE BASE OF LEGACY WIN16 APPLICATIONS.

This was an article published out to the internet by someone in IBM in 1995. We published it on July 29, 1995. It was part of the process to differniate Windows 95 from OS/2. It's a very good read about Windows 95 internals. Curiously, the IBM email address was still on this. I've dropped an email to the address to see if that person is still with IBM.

Can Windows 95 live up to the hype that Microsoft has generated for it? These questions, which are based upon published information about the final beta product in the "Windows 95 Resource Kit" and "Windows 95 Reviewer's Guide," might help you decide.

About Reliability

Q: What happens to 32-bit applications when a Win16 application crashes under Windows 95.

A: They can stop executing. Because Microsoft built Windows 95 using the same System Virtual Machine (VM) model found in Windows 3.1, the operating system is at the mercy of legacy 16-bit applications. If a Win16 program hangs, it can tie up critical 16-bit code modules located in the" System VM. All other processing is halted. BOTTOM LINE: WINDOWS 95 IS NOT A RELIABLE PLATFORM FOR MISSION CRITICAL LINE-OF-BUSINESS APPLICATIONS.

Q: Does Windows 95 protect the contents of its system cache against intrusion by Win32 programs?"

A: No. As with the aforementioned system structures, Windows 95 also fails to protect the contents of its system cache - disk cache, network cache, and CD-ROM cache. As a result, an errant Win32 application can write to memory in use by the cache. The potential results: inaccurate data, corrupted file system entries, etc. BOTTOM LINE: DATA INTEGRITY IS A QUESTIONS MARK WITH WINDOWS 95.

Windows 95 welcome logoQ: How is Microsoft dealing with the issue of Virtual Device Driver (VxD) instability?

A: They aren't. In fact, Windows 95 itself makes heavy use of VxDs to supplement and, in many cases, replace DOS functionality. VxDs are extremely powerful programs that can literally go anywhere and do anything in the operating system. They have free reign to address system memory directly, manipulate hardware, and even replace portions of Windows 95 itself at runtime. This give the creative VxD programmer unlimited flexibility when designing applications that need to modify Windows 95's operation. Microsoft has itself often promoted the VxD interface as a mechanism for gaining good performance with time-critical Windows applications. Unfortunately, the power of the VxD can also be a curse. As more developers begin to exploit this interface - an interface that has only limited controls and almost zero inter-process isolation - a programming free-for-all may result where multiple third party VxDs modify the system in similar ways with unpredictable results. The failure of a single VxD can undermine the stability of the entire Windows 95 environment. BOTTOM LINE: VxDs ARE POTENTIAL DISASTERS WAITING TO HAPPEN IN CORPORATIONS WORLDWIDE.

Q: Is it true that Windows 95 doesn't fully protect its own operating system code against Win32 application failures?

A: Yes. Win32 applications can write to regions of the extreme lower and upper address spaces in the System VM that are critical to the environment's operation. As a result, an errant memory operation can undermine system stability and potentially crash the entire operating system. BOTTOM LINE: WINDOWS 95 MAY BE ONE ERRANT MEMORY OPERATION AWAY FROM TOTAL FAILURE.

Q: When running DOS applications, does Windows 95 fully virtualize the PC's hardware to protect against buggy applications?

A: No. Windows 95 fails to virtualize critical hardware components like the interrupt flag. This, in turn, can lead to a system crash if an errant DOS program becomes unresponsive while interrupts are disabled. BOTTOM LINE: LEGACY APPS ARE THE ACHILLES HEEL OF WINDOWS 95 MEMORY MANAGEMENT.

About Usability

Q: Does Windows 95 track objects dynamically?

A: No. Windows 95 uses a series of static DOS pathnames and .INI files to track the relationship between icons on the desktop and files on disk. For example, the shortcut mechanism of the Windows 95 interface relies on a stored copy of the original's path information when locating and invoking it. If the file is moved within the directory structure, Windows 95 must search the hard disk for it based on file size and date stamp. Although this technique works most of the time, it is limited to searching a single volume - if you move the file to another disk volume, the link is broken completely. And, because Windows 95 will search your entire network if attached, it may take forever if it is connected to, say, five gigabytes of storage. BOTTOM LINE: HELP DESK CALLS WILL BE ON THE RISE AS USERS EXPERIMENT WITH SHORTCUTS AND LONG FILENAMES.

Q: Does Windows 95 make consistent use of drag & drop?

A: No. Windows 95's drag & drop features are applicable to some objects, like files and folders, but not to others. You cannot, for example, drag a dial-up networking connection to the Windows 95 Recycler; nor can you drag objects to the My Computer folder - both are "special" objects in the Windows 95 interface and aren't subject to the normal Windows 95 drag & drop rules. This introduces a level of inconsistency to the interface and a possible stumbling block for new users trying to take advantage of drag & drop. BOTTOM LINE: THE WINDOWS 95 INTERFACE IS INCONSISTENT FROM "FUNCTION TO FUNCTION."

Q: Is the Windows 95 interface consistent and object-oriented?

A: No. For example, while you can invoke the right mouse button pop-up menu on most objects, entries in the Start menu and its submenus are not included. This makes manipulating Start menu entries an awkward process involving the Taskbar properties dialog box and several layers of menus and windows. Since the right mouse button works in most other areas of the interface, the Start button's deviation from this norm exposes Windows 95's object-oriented support as incomplete. BOTTOM LINE: WINDOWS 95 DOES NOT FULLY EXPLOIT O-O TECHNOLOGY

This article was originally published on July 22, 1995.

I cannot  believe that Windows 95 was 12 years ago. The excitement of seeing it run through the paces was fantastic, as it changed computing for millions of people. This is a report I wrote up after attending a marketing event.

My years as a corporate LAN Administrator came out. It was ugly. But, hey, the demonstration of printing on a LAN was absolutely fantastic. I would have called my Microsoft rep the next day to buy a site license . . . What was the demonstration? LAN PRINTING! What is so big about it? Well, a typical scenario when you set up a Windows client is to load Windows on the workstation, load the network drivers, connect to the printer, load the printer drivers and test the printing. Ugh! An hour per machine.

This was originally published on July 8, 1995.

It's always great to look at older articles, and this one is pretty cool. This is a list of shareware award winners 12 years ago. I've gone ahead and checked to see if the companies are still selling software. I appended it to the list.

This was originally published on July 8, 1995. Written by Roger Klien.

When I first began hearing about the newest version of OS/2, better known as Warp, I didn't give it a second thought. You see, I'm an avid Windows user and everyone of my Windows using buddies had warned me that OS/2 was nothing but a headache compared to good ol' Windows. They talked about slowness, installation problems, and lack of support for their favorite Windows apps.

Well, this held me back for awhile but I continued to hear more and more good things about this latest IBM operating system (not to mention the really cool commercials on TV where even nuns are getting Warped)! So finally, I cracked. I decided to give Warp a shot and try it out on a workstation at work. I'm a network administrator for a fortune 500 company and have a few extra machines at my disposal (I wouldn't dare install this on my workstation at home based on what I had heard about earlier versions the OS/2 product)!

To my amazement the installation went flawlessly and I had Warp up and running in about a half an hour. This didn't include time for repartitioning my hard drive but that was my decision. I wanted to have a "Windows" partition and a "Warp" partition. Using the boot manager utilities that came with the product made this a snap. By utilizing the boot manager like this I can either boot into "Warp" mode or "DOS" mode so that I can run my Windows setup. The version of Warp that I looked at didn't include Wi 2 but since I had an existing installation of Windows on my system I was still able to get this functionality. So now I can either boot into "DOS" mode and execute Windows or run Warp and then execute WinOS2 to run my Windows apps.

This first hitch I encountered was the first time I tried to executed WinOS2. Warp would go into a permanent state of limbo. I quickly discovered that this was due to the fact that I was running a PC speaker driver for Windows and when this driver would try to directly access the hardware Warp would lock. Warp tries to handle all hardware calls and obviously wasn't able to handle this. Once I figured this out Windows ran great under Warp and I didn't have any other problems.

As I mentioned earlier, I'm a network administrator so I obviously needed to get Warp up and running on my network. I jumped onto CompuServe and went to the NetWire forum for Novell where I was able to download the client drivers for Warp. In another ten minutes after downloading the software I had Warp talking on my network. The OS/2 Warp LAN Client product, which should be out just about now, is going to have network functionality built in.

For me, Warp's network support is where this product really began to shine! The fact that OS/2 can use network sockets allowed me to log into my network as several different users from the same workstation! For a network administrator this is heaven! This, combined with the fact that OS/2 is truly multi-threading, allowed me to be logged into one server as myself and then trouble shoot a users problem by being logged in as them in another window! No more logging in and back out every time I wanted to te a users account on the network!

Another great benefit of OS/2 is the fact that it uses multiple VDM's (Virtual DOS Machines). This means that every time a DOS window is opened up under OS/2 it looks to the operating system like it is a stand-alone machine. You can even have separate config.sys and autoexec.bat files for each window. The true test of this, and Warp's ability to multi-thread, was when it was time for me to do my monthly upgrade to a proprietary production application we have on the network. Usually this upgrade holds a station hostage for half a day while I continually run over and check on its progress. You see, the application won't allow anything else to be running on the machine, such as remote monitoring software, during the upgrade. This time I opened up a DOS window under Warp and started the upgrade. It ran flawlessly in the background while I went about my administration tasks such as checking my email, running various administration utilities, and logging in as other users in separate te DOS windows, etc. Everything ng ran smooth as silk. Only when I had multiple things running at one time did I notice any slow down and some of these processes where hitting the processor pretty hard.

Overall, I'm very impressed with Warp's ability to run Windows apps, multi-task, and handle network functionality. The install went great and it even set-up an icon for my favorite game Doom! (Yes it was installed on my work computer but for testing purposes only :-) ) Warp is definitely a strong product and I'm looking forward to see what functionality IBM adds to it next. As of right now I would say my time, at least at work, is probably spit evenly between running Warp and Windows. Although, when In a stable, true multi-threading environment, I have no other choice but to get Warped!

IBM Corporation 1000 NW 51st Street Boca Raton, FL 33431 (800) 799-7765 CompuServe: GO WARP URL: http://www.ibm.com/