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Date: Tue, 8 Aug 1995 18:01:21 -0400
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Subject: (Very Long) Microsoft's Response
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A local businessman forwarded the 15 questions to Microsoft, and then
distributed the results. In fairness I feel I should post their response.
To me, most of these answers subtly indicate that Microsoft has permanently
dropped the idea of a strict ( real ) operating system in favor of backward
( out dated ) compatibility.

===================  Response ==============================

The following sections present questions from the posting followed by
Microsoft's answers.

Section I: About Reliability

Q1: What happens to 32-bit applications when a Win16 application crashes
under Windows 95?

Microsoft:  Windows 95 provides a high level of robustness, improved over
Windows 3.1, and is designed to recover from application crashes.  If an
application crashes on Windows 95, the user has the option of terminating
that application, and continuing to run other currently loaded applications.
It is possible, though unlikely, for a poorly written 16-bit Windows
application to crash and temporarily hold up other applications in a Windows
95 system.  The penalty for preventing this entirely would be
incompatibility with a large number of existing Windows applications and/or
unacceptably slow performance on mainstream hardware.  Rather than
unilaterally imposing this penalty on customers, the design of Windows 95
assumes most Windows applications are well-behaved and runs them as they
were designed to be run.  32-bit applications running under Windows 95 add
further robustness improvements such as asynchronous input queues and full
memory protection.  The result is that Windows 95 is substantially more
robust than Windows 3.1 while as fast or faster on mainstream hardware.

This level of compatibility and performance is demanded by customers, and is
not fully provided by OS/2.  Windows NT offers both full protection and
better compatibility than OS/2 for users who require the highest level of
robustness.

What happens to 32-bit OS/2 applications when one of them stops processing
messages such as mouse and keyboard events?  Because OS/2 processes messages
synchronously, when one application hangs or for some other reason does not
process its messages, no other 32-bit application gets any messages either,
so all of them stop.  The lack of separate, asynchronous message queues for
32-bit applications under OS/2 is a major architectural limitation - one
that is not shared by Windows 95.  Windows 95 provides separate,
asynchronous message queues for each 32-bit application, so if one stops
responding, the rest are unaffected. Bottom line:  Windows 95 is more robust
than Windows 3.1 and OS/2 running 16-bit applications, and adds even more
robustness when running 32-bit applications.

Q2: Does Windows 95 protect the contents of its system cache against
intrusion by Win32 programs?

Microsoft:  An application deliberately altering system data structures is
an extremely rare case.  Neither Windows 95 nor OS/2 completely protect
system data areas because to do so would impose large performance penalties,
require more system resources, and introduce incompatibilities with some
applications.

The same choice was made by IBM in the design for OS/2, for probably the
same reason - performance.  It should be noted that an application would
have to be more than just buggy to over-write system components or data in
Windows 95 - it would have to be malicious - deliberately and specifically
accessing those areas.  A similar malicious application would also harm
OS/2. Specifically, does OS/2 protect any of its ring 3 system data pages?
No.  OS/2's system-wide data structures including the window manager,
graphics engine, and non-kernel system components (the shell, desktop,
object model) can be overwritten by an application, causing the system to
crash.  Only Microsoft Windows NT provides virtually complete protection
from an application attempting to access memory outside its own.

Bottom Line: Windows 95 provides a reliable and robust operating system that
achieves excellent performance and compatibility on mainstream systems.

Q3: How is Microsoft dealing with the issue of Virtual Device Driver (VxD)
instability?

Microsoft:  IBM presents no evidence of stability problems with VxDs,
because there is none. VxDs, which are merely device drivers, have been a
fundamental part of the Windows operating system design since 1990 - tens of
millions of people rely on them every day, though they probably don't
realize it since they perform less visible tasks such as network support.
 If there was some kind of wide-spread stability issue with VxDs, Windows
could never have achieved the success that it has.  It is true that in
Windows 95, if a device driver fails, the consequences can be severe, but
that is the case with every PC operating system in existence.

Is OS/2 immune to the problems that can arise if an OS/2 device driver
fails?  No - nor is any other operating system.  Additionally, since OS/2 is
not compatible with Windows VxDs, it cannot run any application or component
(such as Norton Utilities, Visual C++, some communications
applications, and the networking components of Windows for Workgroups) which
requires them.

Bottom line: Windows 95 has comprehensive device support, providing high
performance using a proven and stable device driver architecture.

Q4: Is it true that Windows 95 doesn't fully protect its own operating
system code against Win32 application failures?

Microsoft:  Windows 95 improves robustness, without sacrificing
compatibility.  It is true that Win32 applications have access to the 64K -
4MB range.  The reason is compatibility with MS-DOS and 16-bit Windows
applications and device drivers, something the designers of OS/2 decided to
forgo.  This level of compatibility means, for example,  that users can
continue to use their existing MS-DOS device drivers for devices like sound
cards and those devices will work with 16 and 32-bit applications under
Windows 95. An application would have to deliberately and maliciously write
to a particular system memory area (out of the  whole 4GB range) to cause
problems.  The technical details of IBM's argument are also incorrect - the
extreme lower and upper addresses (near 0 and 4GB) are not addressable to
Win32 applications.  This feature catches a common error in applications
where they may attempt to use null or near null pointers. Also see the
response to question #2.

OS/2 provides no protection from applications writing into critical system
data memory areas.  If an application chooses to write into these areas,
OS/2 can and will crash.

Bottom line:  Windows 95's design successfully achieves high compatibility
with existing applications and hardware, while improving robustness and
reliability over Windows 3.1.

Q5: When running DOS applications, does Windows 95 fully virtualize the PC's
hardware to protect against buggy applications?

Microsoft:  Windows 95 has superior MS-DOS application and device driver
support to OS/2.  While it's unlikely that an MS-DOS application would turn
off interrupts, certain real-mode device drivers will.  If Windows 95
virtualized all of these services and did not allow an application or device
driver to turn off interrupts, then those device drivers wouldn't work.
This would prevent the use of device drivers that support products like
Bernoulli drives.  The choice was made to retain compatibility with these
drivers because some users will require them to support their hardware.

If interrupts are disabled in an unresponsive application on certain bus
architectures under OS/2, OS/2 will also hang.  OS/2 does not provide the
benefit of the use of these device drivers for compatibility reasons, yet
still pays the cost in robustness for allowing this type of operation.

Bottom line:  Windows 95 is the only 32-bit operating system that
successfully retains compatibility with existing real-mode device drivers.


Section II: About Usability

Q6: Does Windows 95 track objects dynamically?

Microsoft:  When it comes to usability, Windows 95 is certainly superior to
OS/2. This is evidenced by the PC World and PC Computing tests reported in
their August 1995 issues in which OS2 loses not only to Windows 95, but also
to Windows 3.1.  Shortcuts and long file names are two of the many usability
improvements in Windows 95 that were driven by extensive
usability testing with the goal of reducing user support burden.To address
this particular question, files that appear on the Windows 95 desktop are
stored in a directory just like any other file regardless of whether they
have long or short file names.  Shortcuts are a special type of file that
contain data on the location of the original object.  If the original object
is moved, Windows 95 will update the location data the next time the object
is accessed.  If the object that a shortcut points to is moved to another
drive, the user must specify the new location.  Windows 95 will only search
a network drive if that was the original location of the object.  Whether
the  object or shortcut uses long file names makes no difference.

OS/2 implements a rough equivalent of Windows 95 shortcuts, called shadows,
however they are less powerful and less easy to use in several ways.
Windows 95 allows easy creation of shortcuts to any type of network
resource. While OS/2 allows the user to create a shadow of a folder on a
network server, the shadow disappears when the computer is rebooted.  If a
Windows 95 user creates a shortcut to a network resource, and later accesses
the shortcut when not connected to the network, Windows 95 is smart enough
to invoke its dial-up networking feature to connect to the network and
access the resource.  If OS/2 users attempt the same operation, they get an
error message.  Unlike Windows 95's shortcuts , OS/2's shadows
cannot point to a particular part of a document, nor can they be embedded
into a document or mailed to another user.   While both shortcuts and
shadows can point to content on the Internet, only Windows 95 is smart
enough to launch a connection to the Internet automatically when a user
opens the shortcut.

Bottom line:  The design of Windows 95 was driven by extensive usability
testing, which resulted in a user interface that surpasses Windows 3.1 and
OS/2 in its ease of use, productivity and reduction of support burden.

Q7: Does Windows 95 make consistent use of drag & drop?

Microsoft:  Again, Windows 95 is demonstrably superior to OS/2, especially
in terms of usability.   Windows 95 makes dragging and dropping objects both
easy, and safe.  My Computer is designed to show the objects that are on the
user's computer: the disk drives, network connections, and related settings.
It would be confusing to allow users to add new items to this list since
those items would not be disk drives, net connections, or settings.
Dragging a dial-up network connection to another location automatically
creates a shortcut to that connection, leaving the original in the dial-up
networking folder where it belongs.  It certainly would not make sense to
create a shortcut in the recycle bin, where it would then be discarded.

OS/2 forces the user to remember inconsistent dragging techniques.  The
non-default (right) mouse button is used to drag objects, but the left mouse
button is used to drag windows, and to drag objects in the Windows UI and in
Windows applications running under OS/2.  Objects cannot be dragged from
windows in OS/2 to Windows-based  applications.

Bottom line:  Windows 95 provides the easiest, most productive user
interface of any PC operating system.  Don't take Microsoft's word for it,
read the August issues of PC World and PC Computing.

Q8: Is the Windows 95 interface consistent and object-oriented?

Microsoft:  Clicking the right mouse button on the Windows 95 Start Button
produces a complete set of options for manipulating items contained on the
Start Menu including Open, Explore, and Find.  These features make it very
easy and efficient to add, change, and delete those items.  How is object
oriented technology (which is a software development approach) relevant to
how users interact with the user interface of an operating system?

Bottom line:  See question 7.

Section III: About Windows 95 and Multitasking

Q9: Can Windows 95 preemptively multitask Win16 applications?

Microsoft:  Both Windows 95 and OS/2 take the approach of running 16-bit
Windows applications cooperatively.  Windows 95 cooperatively multitasks
existing Windows applications because that is the best way to achieve high
compatibility with those applications.  Windows 95 adds an improved user
interface, better robustness, greatly increased system resource capacity,
32-bit printing, networking, disk I/O, multimedia, communications
components, and more - all of which provide benefits when using 16-bit or
32-bit applications, without compromising compatibility or performance.  All
new 32-bit applications designed for Windows 95 offer fully preemptive
multitasking and can use multiple threads of execution.

OS/2 provides a non-default option to run 16-bit Windows applications in
separate, preemptively multitasked sessions.   However this comes at great
cost in terms of memory - since a copy of Windows 3.1 is loaded for each
application - and compatibility because OLE-based applications cannot
exchange information when run in separate sessions.  If the separate session
option really provides tangible benefits worth its costs, why is it not
enabled by default in OS/2?  OS/2 is not compatible with any of the 32-bit
applications designed for Windows 95, and which run with preemptive
multitasking.

Bottom line:  Windows 95 adds significant value in running 16-bit Windows
applications including an improved user interface, better robustness,
greatly increased system resource capacity, 32-bit printing, networking,
disk I/O, multimedia, communications components, and more.

Q10: Are there any caveats to multitasking Win32 applications under Windows
95?

Microsoft:  Windows 95 provides excellent multitasking of 32-bit
applications while maintaining compatibility with 16-bit applications
designed for Windows 3.1.  Windows 95 provides this high-level of
compatibility by running 16-bit Windows applications the way they were
designed to be run, using time-tested, proven code for compatibility and
lower memory requirements.  The result is good cooperative multitasking and
fast performance with 16-bit applications plus great preemptive multitasking
of 32-bit applications.   For users that require a high level of
compatibility with 16 and 32-bit Windows applications, plus the option to
run 16-bit Windows applications preemptively, Microsoft offers Windows NT.

OS/2, which has a significant amount of 16-bit code itself, requires more
memory to run 16-bit Windows applications, and runs them slower than Windows
95.  OS/2 also adds compatibility problems if its preemptive option is used,
and is totally incompatible with 32-bit Windows applications designed for
Windows 95 and Windows NT.

Bottom line:  Windows 95 and Win32 applications provide smooth preemptive
multitasking.

Q11: What happens to Windows 95's multitasking when you run a mixture of
application types?

Microsoft:   Windows 95 runs both 16 and 32-bit applications simultaneously
and allows multitasking both types of applications.  When a 16-bit
application is executing on Windows 95, it's control of the CPU lasts for
only a very short time, after which time is allocated to other running
applications on a preemptive or cooperative basis depending on the
application.  The user experience, in most cases is that all applications
run essentially at the same time, regardless of whether they are 16 or
32-bit.  Readers who are concerned about this can try a simple test:  print
a long document from Microsoft Word 6.0 (16-bit), while performing a copy of
a large file using the Windows 95 Explorer (32-bit).  Both operations will
proceed smoothly and simultaneously to completion.  As users migrate to
32-bit applications, multitasking becomes even smoother.As stated above,
OS/2 provides a non-default option for running 16-bit Windows applications
preemptively, but this option requires significantly more memory (so
applications run slowly), and introduces compatibility problems such as the
inability to use OLE to exchange data between applications.  OS/2 will not
run 32-bit Windows applications at all so users cannot take advantage of
their superior multitasking if they use OS/2.

Bottom line:  Windows 95 runs existing 16-bit applications on top of new
32-bit system components, which provide smooth operation along with the
preemptive multitasking of new 32-bit applications.

Q12: Does Windows 95's multitasking resolve any of Windows 3.1's
multimedia-related deficiencies?

Microsoft:  Windows 95's new 32-bit multimedia subsystems give a tremendous
boost to its playback performance, making even full screen full motion video
playback possible on high end systems.  Among the many improvements in this
area are an improved, swappable and tunable CD-ROM cache, 32-bit video
CODECs, game development tools, plus high-performance graphics and disk I/O.
The May 1995 issue of NewMedia magazine was particularly
enthusiastic about the multimedia improvements in Windows 95, stating "The
potential benefits - especially to multimedia - of a 32-bit, multitasking,
multithreading system are mind-blowing."
Already, multimedia titles for Windows 3.1 far outnumber and outsell titles
for OS/2 (go into any software reseller and try to locate even one OS/2
multimedia title).  Windows 95 is receiving a high-level of attention and
investment from multimedia ISVs who are eager to take advantage of Windows
95's multimedia improvements, so there will soon be a large number of games
and titles designed specifically for Windows 95 (these applications will not
run on OS/2 at all).

Bottom line:  Windows 95 offers significant improvements in all areas of
multimedia performance.

Section IV: About Windows 95's relationship to DOS

Q13: Does Windows 95 really do away with DOS?

Microsoft:  Windows 95 employs new 32-bit code in all areas in which it
produces performance and/or robustness improvements, and uses time-tested,
proven 16-bit code in some areas for compatibility and reduced memory
requirements.  To provide compatibility that allows 32-bit applications to
exchange data with 16-bit applications and device drivers, Windows 95
continues to use data structures such as the MS-DOS PSP.  It is highly
unlikely that users would ever run out of real-mode memory under Windows 95
since each application only allocates one 256 byte PSP (out of 655,360 bytes
of real mode memory), nor are any additional MS-DOS memory managers
required.  Virtually all of the things that take up conventional memory
under Windows 3.1 (network, CD-ROM drivers, sound drivers, etc) are now
implemented as 32-bit protect mode components in Windows 95.  So there is
even less of a chance that real mode memory will become an issue.  For
example, a typical system which has device drivers for a CD-ROM drive, SCSI
card, network card and protocols, and sound card will still have over 600K
free conventional memory since all of those device drivers are now 32-bit
and loaded into protect mode memory.

OS/2 employs 16-bit code in performance-critical areas such as the file
system and network components.  OS/2 also exhibits lower compatibility with
16-bit Windows applications than Windows 95, even though it runs them using
16-bit Windows 3.1 code.  OS/2 is also totally incompatible with 32-bit
applications designed for Windows 95 and Windows NT.  So, not only is OS/2
compromised by the use of 16-bit code in performance-critical areas, it has
poor Windows application compatibility as well.

Bottom line:  Windows 95 is the only operating system that provides 32-bit
power while retaining a high level of compatibility with real-mode device
drivers and existing applications.

Q14: What is Single MS-DOS Application mode and how does it affect other
running applications?

Microsoft:  Windows 95 provides the MS-DOS Mode compatibility feature for
running MS-DOS applications (typically games) that require absolute control
over the hardware of the PC.  Microsoft tested approximately 1,300 of the
most demanding MS-DOS applications under Windows 95, and found that only one
in ten require the use of MS-DOS Mode.  If a real-mode device driver is
required to run the MS-DOS Mode application, it can be specified and
automatically loaded via a CONFIG.SYS and/or AUTOEXEC.BAT file unique to
that application.  Windows 95 will suggest the use of MS-DOS Mode
automatically for applications that are known to require it, or when
applications perform certain operations - so users do not have to perform
special operations to run their applications.  Windows applications, which
are the vast majority of applications sold and used, do not require MS-DOS
Mode.  OS/2 also provides a way to boot MS-DOS when an MS-DOS application
does not work under OS/2, but it is far less convenient, requiring the user
to issue BOOT /DOS, run their application, and then type BOOT /OS2 to return
to OS/2.

Bottom line:  Microsoft has done the extra work that allows Windows 95 to
run even poorly behaved MS-DOS applications, significantly improving MS-DOS
application compatibility over Windows 3.1.

Q15: How does Windows 95 handle real mode DOS device drivers?

Microsoft:  Windows 95 does not depend on real mode MS-DOS device drivers.
Windows 95 is however, compatible with existing real-mode drivers if they
are required for a particular device.  Windows 95 is the only 32-bit
operating system that retains compatibility with existing real mode device
drivers.  This means that users can continue to use devices with Windows 95
even if they do not have 32-bit device drivers.  Device drivers loaded via
CONFIG.SYS are available to all DOS sessions since that is what users
expect, not wishing to maintain multiple CONFIG.SYS files.   Most users will
run few if any real-mode drivers since Windows 95 provides a large selection
of new 32-bit drivers that support most popular devices.  In fact most users
won't even need to maintain a CONFIG.SYS file.OS/2 does not allow the use of
real-mode MS-DOS device drivers for network cards, sound cards, graphics
adapters, CD-ROM drives, or other devices that users need to run under OS/2.
This means that users often cannot use a particular device under OS/2 since
its device support is not as comprehensive as that of Windows 95.  OS/2 also
requires users to maintain a complex and large (often over 200 lines)
CONFIG.SYS file when adding or removing device drivers.  The ability to have
multiple copies of CONFIG.SYS files under OS/2 adds even more complexity for
minimal benefit - most users would never take advantage of this "feature".

Bottom line:  See question 14.

==========================  end of response  ====================
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