15 Questions to Ask Microsoft about Windows 95

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        | 15 Questions to Ask Microsoft about Windows 95  |                    
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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.             
                                                                               

Q: 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               
                                                                               
                                                                               

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.                                                   
                                                                               

Q: Are there any caveats to multitasking Win32 applications under

  Windows 95?                                                                  

A. Yes. In its effort to maintain a high degree of backward

  compatibility while simultaneously minimizing the RAM requirements           
  of the operating system, Microsoft has chosen to rely on its existing,       
  Windows 3.1-era USER (window management) and Graphics Device                 
  Interface (GDI) modules rather than create new, 32-bit versions.             
  In order to utilize this older, 16-bit code in potentially                   
  preemptive (with regard to Win32 applications), 32-bit                       
  multitasking environment of Windows 95, Microsoft was forced to              
  serialize access to USER and GDI.  As a result, only a single Win32          
  or Win16 program can access these critical modules at any given time.        
  This hurts application performance on heavily loaded systems                 
  as programs are forced to "line-up" and wait for a chance to                 
  execute a USER or GDI routine.                                               
  All USER calls (for both 16 and 32-bit applications) are serialized          
  and handled by the 16-bit code, while the majority of GDI calls              
  are similarly handled (the other 50 percent are handled by newer             
  32-bit routines).                                                            
                                                                               
  BOTTOM LINE:  WINDOWS 95'S MULTITASKING IS BEST DESCRIBED AS                 
  PREEMPTIVELY CHALLENGED.                                                     
                                                                               

Q: What happens to Windows 95's multitasking when you run a mixture of

  application types?                                                           

A: It reverts to a cooperative multitasking model. Windows 95's

  continued reliance on the single system VM model of Windows 3.1              
  places the operating system's multitasking capabilities                      
  at the mercy of the lowest common denominator: the 16 bit                    
  Windows

application. Whenever a Win16 application is running,

  the operating system's multitasking capabilities are                         
  compromised by the need to allow such programs to execute                    
  "undisturbed" for as long as they require.  As a result, when                
  multitasking a mixture of applications - Win16 and Win32 - true              
  preemptive operation is impossible since, at any given time, a               
  16-bit  application may require exclusive control of the CPU.                
  Worse still, since the Win16 application is typically                        
  executing a portion of the 16-bit USER or GDI code - access                  
  to which must be serialized among processes -all other processes,            
  including Win32 applications, are blocked from executing.  The net           
  result is what would be best described as "semi-preemptive"                  
  multitasking.                                                                
                                                                               
  BOTTOM LINE:  WHEN WIN16 APPLICATIONS ENTER THE MIX, WINDOWS 95 TAKES        
  ON AN ALTERNATE PERSONALITY WINDOWS 3.1                                      
                                                                               

Q: Does Windows 95's multitasking resolve any of Windows 3.1's

  multimedia-related deficiencies?                                             

A: Not really. Windows 95's inconsistent multitasking performance -

  a byproduct of the single System VM model - compromises                      
  its performance as a serious multimedia production platform.                 
  Complex .AVI clips break up noticeably when a significant I/O strain         
  is placed on a Windows 95 system.  Even simple operations, like              
  opening an application program, can have a negative impact on                
  multimedia playback.                                                         
                                                                               
  BOTTOM LINE:  YOU STILL CAN'T PLAY MULTIMEDIA AND DO HEAVY I/O               
  SIMULTANEOUSLY.                                                              
                                                                               

About Windows 95's relationship to DOS

Q: Does Windows 95 really do away with DOS? A: No. Windows 95, though touted as a completely new, 32-bit operating

  system, is in fact still based on DOS technology that dates                  
  back to the early 1980s.  Under Windows 95, even                             
  Win32 applications rely on at least a few data structures within             
  the real mode DOS environment (most notably, they all maintain real          
  mode PSPs).  Despite Microsoft's claims to the contrary, Windows 95          
  is highly sensitive to the configuration of a PC's real mode DOS             
  environment.  If, for example, the available conventional memory             
  in the System VM - the DOS virtual machine where all 16-bit                  
  Windows applications and some Windows 95 codes executes - dips below         
  a certain level, Windows 95 will report "out of memory" messages             
  when you try to open additional Win16 or Win32 programs.  This is            
  unrelated to the well known System Resources phenomena, and the              
  only real solutions are to either replace as many real mode device           
  drivers as possible with VxDs or to invest in a third party memory           
  manager to optimize the pre-Windows 95 DOS environment.                      
                                                                               
  BOTTOM LINE:  WINDOWS 95 CAN BE VIEWED AS DOS/WINDOWS with a new             
  INTERFACE AND SOME NEW VxDs.                                                 
                                                                               

Q: What is Single MS-DOS Application mode and how does it affect other

  running applications?                                                        

A: Microsoft touts Single MS-DOS Application (SMA) mode as its ultimate

  solution to any and all DOS compatibility complaints. SMA is                 
  essentially real mode DOS, except that instead of booting DOS and            
  then loading Windows, the order has been reversed: you first boot            
  Windows 95, then "unload" it as the machine is reset into the real           
  mode of SMA. This indeed eliminates virtually all remaining                  
  DOS application incompatibilities since the PC is no longer                  
  running in V86 protected mode - it has been reset to real mode,              
  loaded with a copy of DOS, and left at a command prompt. What                
  Microsoft doesn't like to admit, however, is that to invoke an               
  SMA-dependent application is to essentially shut-down Windows 95 -           
  all running applications are closed, network connections are                 
  severed, and VxD support for peripherals like CD-ROM drives                  
  disappears. To maintain these functions you need to add real mode            
  DOS device drivers to your system and then configure them via the            
  SMA dialog box.  And since Windows 95 is no longer running,                  
  any users who are connected to shared resources on the system are            
  disconnected when it enters into SMA mode.                                   
                                                                               
  BOTTOM LINE:  SMA IS REALLY ONLY A VIABLE SOLUTION FOR HOME USERS AND        
  OTHER NON-NETWORKED ENVIRONMENTS                                             
                                                                               

Q: How does Windows 95 handle real mode DOS device drivers? A: Windows 95's dependency on the real mode DOS environment

  undermines the product's ability to support DOS applications.                
  Because Windows 95 relies on an "image" of the pre-Windows 95                
  boot-up environment when creating the System VM, and because                 
  subsequent DOS virtual machines are similarly based on this                  
  boot-up image, Windows 95 users are forced to load any required              
  real mode device drivers as part of the original boot-up                     
  CONFIG.SYS file.  The ramifications of this limitation are                   
  significant:  each and every DOS session under Windows 95                    
  contains a running copy of, and surrenders valuable conventional             
  or upper memory to, real mode device drivers.  This is true even             
  if the drivers are not required or desired in a particular                   
  DOS session.                                                                 
                                                                               
  BOTTOM LINE:  THERE'S NO WAY TO LOAD A REAL MODE DRIVER INTO A               
  SPECIFIC DOS SESSION -- IT'S AN ALL OR NOTHING PROPOSITION.