Windows Desktop Family Integration into Business Environments

Overview

For some, it is difficult to fathom that some organizations in the world are still running MS-DOS® as their mainstream client operating system platform without a graphical user interface (GUI). Moreover, they still have MS-DOS applications, very low-end personal computers (PCs) and no networking capabilities. On the other extreme, we have organizations whose business needs demand the use of very sophisticated operating systems, hardware and applications to deliver the level of performance required.

From both spectrums, organizations are currently going through the exercise of choosing their next operating system. The candidates are Microsoft® Windows® 3.11, Microsoft Windows® for Workgroups 3.11, Microsoft Windows 95 and Microsoft Windows NT™ Workstation.

The rapid decreases in price-performance ratios due to innovations in PC components, especially with the introduction of Intel® i486™ and Pentium™ microprocessors, has facilitated the development of high end operating systems that make use of the power provided by hardware advancements.

Although the PC has made dramatic gains over the past decade, a number of problems keep current PC users from making better use of PCs at work and at home. Below you will find some of the issues associated with PC’s:

• PCs are intimidating and complicated. Many people perceive PCs as hard to use. Simple tasks, such as connecting to a printer or sending a fax, are too complicated for the typical computer user. This prevents current users from getting the most out of their PC and discourages non-users from using a PC.
• PCs are difficult to install and configure. For anyone but a trained technician, installing or configuring a device on a PC today is a daunting exercise that may be difficult, time-consuming, and frustrating. The result is an increase in the cost of deploying PCs in the workplace and a reduction in the demand for PC products in the home.
• PCs are expensive to maintain and support. The cost of PC hardware is small relative to the costs of installation, configuration and maintenance. Additional costs include training and support for the PC user. These costs must be reduced to make PCs a more indispensable tool for business computing.
• PC information access is difficult for mobile or remote users. People who work from a variety of locations have a hard time accessing their data at the office or at home. Developing easy-to-use portable systems, that are well integrated with desktop systems, is difficult because of limitations in the current PC architecture.
• PCs aren’t powerful enough for advanced users. Many experienced PC users want to perform multiple tasks (such as printing and downloading a file in the background when they are working on a different task in the foreground) while still getting smooth performance from their system.

• Platform Architecture
• Platform hardware requirements
• Advantages
• Disadvantages
• Suggested areas where the platform will fit

Windows 3.11

Platform Architecture

Three files make up the Microsoft Windows core components: Kernel, User, and GDI.

The kernel files (KRNL286.EXE or KRNL386.EXE) control and allocate all the machine resources to manage memory, load applications, and schedule program execution and other tasks.

USER.EXE creates and maintains windows on the screen, carrying out all requests to create, move, size, or destroy a window. USER.EXE also handles requests regarding the icons and other components of the user interface. USER.EXE directs input to the appropriate application from the keyboard, mouse, and other input sources.

GDI.EXE controls the Graphics Device Interface, which executes graphics operations that create images on the system display and other devices.

The picture below displays where the core component files are located, viewed from the entire OS. The flow of an application call traverses the following layers:

• Application makes an API call.
• Depending on the API call, one of the components is invoked.
• Again, based on the function to be accomplished, the proper driver is invoked.
• The final step is the access of the hardware.

Platform Hardware Requirements

Hardware requirements differ with Windows depending on its mode. Windows can run in two different operating modes: standard mode and 386 enhanced mode. For both of these, the processor runs in protected mode. Windows automatically runs in the appropriate mode, depending on the computer hardware and the amount of system. Below are the hardware requirements for each mode:

• Standard mode requires a PC with an 80286 processor (or higher) and 256K of free conventional memory and 192K of free extended memory. This mode provides access to extended memory using application swap files. Windows does not use virtual memory. Non-Windows applications run in full screen. The values specified basically allow Windows to load. When running two or more applications simultaneously, we recommend a minimum of six MB of memory.
• Enhanced mode requires a PC with an 80386 processor (or higher) and two megabytes or more of memory (256K of free conventional memory and 1024K extended memory). Windows 386 enhanced mode provides access to the virtual memory capability of the 80386 processor, so that Windows applications can use more memory than is physically available. Windows 386 enhanced mode also allows multitasking of non-Windows applications and more control over those applications. For example, you can run a non-Windows application in a window. Again the recommended minimum for this mode is six MB of memory if the system will be doing any other work beyond loading the Windows product.

Windows takes approximately 8 to 10.5 MB on each client hard disk. Windows can also be installed on a server and shared among several clients. This configuration requires 16 MB on the shared network server disk and 300K on each workstation hard disk. One should budget for applications space.

Advantages

• A graphical user interface that is consistent and easy to learn.
• Applications in the market adhere to the GUI standard and therefore, the basic functions of one Windows application, also apply to all other Windows applications.

The 32-bit Disk Access feature of Windows, also known as FastDisk, was first introduced with Windows 3.1. It brought new technology to users of the Windows operating system and delivered improved performance over Windows 3.0.

Windows 3.1 32-bit Disk Access can be utilized as a set of protected-mode device drivers that work together to enhance your system’s BIOS. It filters interrupt (Int) 13H calls to the hard disk controller and directs them in the most efficient way for the system—either through the 32-bit interface with the hard disk controller or through the system BIOS.

The use of 32-bit Disk Access provides improved system performance for running MS-DOS-based applications. Using 32-bit Disk Access allows more pageable memory in Windows to page MS-DOS-based applications to disk, this frees enough RAM for applications when they need it. The 32-bit Disk Access feature also improves the overall performance of Windows, making the system run much more quickly. For example, switching between MS-DOS-based applications is faster with 32-bit Disk Access.

For other features and benefits of 32-bit disk access, please refer to the Windows Resource Kit.

Disadvantages

Pre-emptive Multitasking

Does not support pre-emptive multitasking.

Resource Problems

Many users have probably seen “Out of Memory” error messages when running multiple Windows-based applications under Windows 3.1, even though the system still reports several megabytes of available free memory. What users typically encountered was a condition where the system was not able to allocate an internal memory resource in a Windows API function call due to not enough space available in a region of memory called the heap. For further technical information, please refer to the Windows Resource Kit.

Networking

All drivers for the network are loaded from MS-DOS and therefore make use of conventional memory. This leaves less conventional memory available for applications.

No autodetection for devices such as network interface cards and modems.

Remote Management Capabilities

Windows was not designed to provide remote management capabilities via SNMP, DMI, Win32® or RPC. Each PC maintains its own AUTOEXEC.BAT, CONFIG.SYS, and any INI files required for Windows and applications installed on the system. There is no central point where all configuration is maintained, causing the administrator or support personnel a trip to each PC when it needs support.

Underlying Operating System

MS-DOS is loaded prior to Windows. Therefore, Windows inherits many of the shortcomings of the MS-DOS operating system. Some of the shortcomings are:

• Conventional memory limitations.
• Openness of the OS which allows applications to gain access to system resources.
• Some drivers must still be loaded in conventional memory.

Adding a printer or a CD-ROM can be complicated for the typical user.

Memory Addressing

Depending on the chip set and motherboard, it is possible for WFW to only address 16 MB of memory. This is not always the case. Confirm the hardware being considered will support more than 16 MB of memory.

Suggested Areas Where the Platform Will Fit

Windows 3.11 is not in the drawing boards for any modifications. Therefore, making a decision to remain or migrate to this platform must be based on its current features and benefits. This platform has been deployed under the following circumstances:

• Migrated to Windows approximately a 18 months ago. This move was viewed as a great transition from the MS-DOS environment.
• Small office with one server. No need for anything else other than a graphical user interface. Network drivers are loaded outside of Windows but it does not pose any memory constraints.
• Migrated to Windows 18 months ago and are waiting for the release of Windows 95.
• WFW was seen as a possible administrative headache, due to its peer to peer capabilities. Not knowing that those services could be turned off, the decision was made to migrate to Windows.

Platform Architecture

WFW has the same core architecture as Windows. There are areas which have been enhanced beyond the Windows which will be covered as part of the advantages. For exact details on all architecture changes please refer to the Windows for Workgroups Resource Kit.

Platform Hardware Requirements

Windows for Workgroups can execute in standard mode or enhanced mode. The requirements differ between each mode. Below you will find the requirements for each:

Standard Mode

To run Windows for Workgroups in standard mode, you need an Intel 80286 (or higher) computer with a minimum of 2MB of memory (recommend 6MB minimum).

A Windows for Workgroups workstation running in standard mode can act as a client in the workgroup, and thus can use shared resources. However, a workstation running in standard mode can’t share resources. This is due to the virtual device drivers which can only run in 386 enhanced mode.

See figure below for a visual on what is needed to run in standard mode.

Enhanced Mode

To run Windows for Workgroups in 386 enhanced mode, you need an Intel 80386 (or higher) computer with a minimum of three MB of memory (six MB of memory is recommended).

A Windows for Workgroups workstation running in 386 enhanced mode can act as both a client and a server in the workgroup, and therefore can both access and share resources. A workstation running in 386 enhanced mode can also use the Network DDE functionality provided with Windows for Workgroups to access and share information with remote workstations.

See figure below for a visual on what is needed to run in enhanced mode.

Disk Space Required

Windows for Workgroups takes approximately 10.5 to 15 MB on each client hard disk. WFW can also be installed on a server and shared among several clients. That configuration requires 21 MB on the shared network server disk and 1.2MB on each workstation hard disk.

Advantages

Microsoft Mail

Mail, for Windows for Workgroups 3.11, is an easy-to-use electronic mail system for small workgroups in a Windows for Workgroups 3.11 environment. Mail for Windows for Workgroups 3.11, requires one user in the workgroup to install a Windows for Workgroups Postoffice in a shared directory. Other users in the workgroup can use this Postoffice for exchanging mail messages.

Schedule+

Schedule+ is a personal scheduling tool that helps track important appointments and tasks, block out time for meetings, and record personal notes. Reminders can be set on the service at a specified time prior to scheduled appointments or tasks. These features make Schedule+ extremely useful as a personal organizer on a standalone machine.

In addition to being useful on a standalone machine, Schedule+ offers other features in a networking environment. In a networking environment, Schedule+ becomes a workgroup scheduling tool. When a meeting needs to be scheduled with co-workers, their calendar and times they are available can be easily viewed. For further information on Schedule + refer to the Microsoft Mail Users Guide.

Peer-to-Peer Communications

Windows for Workgroups provides peer-peer networking capabilities. That is to say that directories and printers can be shared amongst other Windows for Workgroups, Workgroup Connection, or LAN Manager clients. Share level security is built into the networking software.

Improved Performance and New 32-Bit Components

Windows for Workgroups 3.11 incorporates 32-bit network adapter card drivers that comply with Network Device Interface Standard (NDIS) 3.0 and 32-bit File Access. Providing a full 32-bit code path from the network adapter card, through the network protocol and network client and server software, to the hard disk in the local computer. These features provide improved performance for network I/O and disk and file I/O access.

Improved Configurability and Administration for MIS

Through the use of the administrator configuration utility, ADMINCFG.EXE, system administrators can control Windows for Workgroups 3.11 functionality by disabling file and/or printer sharing if necessary, along with defining password settings that can be enforced on computers running Windows for Workgroups or Workgroup Add-on for MS-DOS.

Minimal Use of Conventional Memory

Windows for Workgroups 3.11 has only a 4-kilobyte conventional memory footprint when using 32-bit network drivers. This allows large MS-DOS-based applications to run under Microsoft Windows in a networking environment.

Full Support for Windows NT and Windows NT Server

Windows for Workgroups 3.11 provides the best level of client support for Microsoft Windows NT™ and Windows NT Advanced server. This is because Windows for Workgroups 3.11 offers a client that fully supports the improvements made to the 32-bit networking components. It also takes advantage of enhanced security available with a Windows NT domain. In addition, Windows for Workgroups 3.11 includes the Remote Access Services (RAS) client for remotely accessing other Windows for Workgroups or Windows NT computers. This is accomplished by dialing into the RAS server provided with Windows NT and Windows NT Advanced Server.

Improved Support for Novell NetWare Environments

Windows for Workgroups 3.11 features the ability to run on top of Open Datalink Interface (ODI) network adapter card drivers, support peer sharing services over the IPX protocol, and includes a routable 32-bit IPX/SPX compatible transport with NetBIOS services allowing Windows for Workgroups computers to participate on an IPX backbone including through an IPX router.

Better Support for Standalone Computers

Windows for Workgroups 3.11 features an option to not install the networking components. This provides improved performance and new functionality to standalone computer users as well as users on a network.

Incorporation of Microsoft At Work Components

Windows for Workgroups 3.11 features the first PC-based implementation of Microsoft At Work™ technology in the form of Microsoft At Work fax messaging.

Configuration Has Simplified by Removing Network Drivers from CONFIG.SYS

NDIS network adapter card drivers and Windows for Workgroups 3.11 support drivers are loaded from the SYSTEM.INI file rather than the CONFIG.SYS and AUTOEXEC.BAT files. This results in only one real-mode support driver being loaded in the CONFIG.SYS file and one command line present in the AUTOEXEC.BAT file, thereby simplifying the system configuration. More information about this configuration change from Windows for Workgroups 3.1 is discussed in the next section.

32-Bit File Access

See figure above as reference. Windows for Workgroups 3.11 extends the 32-bit Disk Access system architecture of Windows 3.1 and Windows for Workgroups 3.1 to provide 32-bit File Access as well. 32-bit File Access provides a 32-bit code path for Windows to access and manipulate information on disk by intercepting the MS-DOS Int 21H services in protected mode, rather than handling the Int 21H services in real mode by MS-DOS. This results in greatly improved disk I/O performance when reading information from or writing information to a supported disk device configuration over a similarly configured computer running Windows 3.1 or Windows for Workgroups 3.10. For further technical information please refer to the Windows for Workgroups resource kit.

Disadvantages

All disadvantages associated with Windows are the same with Windows for Workgroups. The following Windows disadvantages have already been addressed with Windows for Workgroups:

• Autodetection of devices such as network interface cards and modems

Suggested Areas Where the Platform Will Fit

Windows for Workgroups has been the path of least resistance for organizations looking to upgrade from Windows. The decision to migrate to WFW has been made due to the following major advances from Windows:

• Improved network performance
• Reduced memory usage
• Peer-to-Peer communication capabilities
• Integration of networking components, which made it easier to administer
• Including of Microsoft Mail’s client software

• Cannot wait for Windows 95
• Windows NT has hardware requirements that are too costly
• Required more conventional memory space than they were able to retrieve using memory management software and regular Windows
• Migrating from MS-DOS to the best Windows product they can afford
• 32 bit TCP/IP drivers required for Dynamic Host Configuration Protocol

Platform Architecture

The figure below illustrates the layout of the base system architecture for Windows 95. Components of the system are divided between Ring 0 and Ring 3 code, offering different levels of system protection. The Ring 3 code is protected from other running processes by protection services provided by the Intel processor architecture. The Ring 0 code consists of the low-level operating system services such as the file system, and virtual machine manager.

This figure also depicts the way that MS-DOS-, Win16-, and Win32-based applications run in the system.

32-Bit Versus 16-Bit Components

Windows 95 uses a combination of 32-bit and 16-bit code to provide a good balance between delivering compatibility with existing applications and drivers. Decreasing the size of the operating system working set, and offering improved system performance over Windows 3.1.

Windows 95 is a 32-bit preemptive, multitasking operating system that implements some 16-bit code to provide compatibility with existing applications. In general, 32-bit code is provided in Windows 95 to maximize the performance of the system, while 16-bit code balances the requirements for reducing the size of the system and maintaining compatibility with existing applications and drivers.

All of the I/O subsystems and device drivers in Windows 95, such as networking and file systems, are fully 32-bit, as are all the memory management and scheduling components (the kernel and virtual memory manager). The figure below depicts the relative distribution of 32-bit versus 16-bit code present in Windows 95 for system-level services. As can be seen from the figure, the lowest-level services provided by the operating system kernel are provided as 32-bit code. Most of the remaining 16-bit code consists of hand-tuned assembly language, delivering performance that rivals some 32-bit code used by other operating systems available on the market today.

Platform Hardware Requirements

While the specs for Windows 95 maintains that a 386DX with four MB will work, an Intel 486 with a minimum of eight MB of RAM as the minimum configuration recommended. As you increase memory the system performance increase is quite dramatic. This recommendation is based on M7 beta code.

Disk Space Requirements

Windows 95 will take at minimum 30MB and maximum 40MB of disk space.

Advantages

Preemptive Multitasking

Unlike the cooperative multitasking used by Win16-based applications under Windows 3.1, 32-bit Win32-based applications are preemptively multitasked in Windows 95. The operating system kernel is responsible for scheduling the time allotted for running applications in the system. Support for preemptive multitasking results in smoother concurrent processing and prevents any one application from utilizing all system resources without permitting other tasks to run.

Win32-based applications can optionally implement threads to improve the granularity at which they multitask within the system. The use of threads by an application improves the interaction with the user and results in smoother multitasking operation.

Flat Address Space

Win32-based applications benefit from improved performance and simpler construct due to the ability to access memory in a linear fashion. Win32 applications are not limited to the segmented memory architecture used by MS-DOS and Windows 3.1. In order to provide a means of accessing high amounts of memory using a 16-bit addressing model, the Intel CPU architecture provides support, called segments, for accessing 64K chunks of memory at a time. Applications and the operating system suffer a performance penalty under this architecture due to the necessary manipulations required by the processor for mapping memory references from the segment/offset combination to the physical memory structure.

The use of a flat address space by Windows 95’s 32-bit components and for Win32-based applications will allow developers to write software without the limitations or design issues inherent with segmented memory architecture.

32-Bit File System Architecture

The file system in Windows 95 has been re-architected from Windows 3.1 to support the characteristics and needs of the multitasking nature of the Windows 95 kernel.

Plug and Play

Windows 95 is the first operating system product to support the Plug and Play architecture. The Plug and Play architecture enables automatic installation and dynamic reconfiguration of Plug and Play devices.

Plug and Play devices record their configuration information in INF files. The INF file contains a list of system resources required by the device, the drivers needed to operate it, and device-specific configuration and status information. When the device is installed, the Plug and Play system allocates system resources (DMA channels, IRQs, base I/O addresses, etc.) to the device, loads the device driver, and writes the information about allocated system resources and the device-specific information into the Windows Registry. Once installed, the device settings can be configured via the Registry APIs.

The Plug and Play system also places information in the Registry regarding system resources allocated to non-Plug and Play devices. However, if vendors of legacy devices want to report management information beyond that exposed by the Plug and Play system, they will need to modify their drivers to do so.

Windows 95 Desktop Management Features

Windows 95 is the first version of Windows expressly designed for manageability. The design ensures that management of the Windows 95 PC is accessible both locally, and remotely via a privileged network manager. Network security is used to determine administrator privileged accounts using pass through security. Windows 95 also provides for logical separation PC user and the underlying PC configuration. This means that the PC and the user configurations and privileges can be managed independently. It also means that if a network manager chooses, a user can be enabled to “rove” on the network. That is, logon from virtually any PC on the network and operate in their desktop with the correct settings and network privileges. Additionally, it means that a single PC can be shared by multiple users, each with a different desktop configuration and differing network privileges.

User Configuration Management

In many companies, employees share multiple PCs. Windows 95 supports user profiles to enable users to access their personal groups, applications, and data from any system on the network. This “multiple-user mode” can also be provided on a stand-alone system. This capability is provided through the Windows Registry, which stores per-user configuration information separately from system information so that each of these can be managed separately. Per-user configuration information can include preference data such as favorite screen colors, mouse click speed, and program groups.

Desktop Configuration Control

Windows 95 provides administrators the ability to lock the system configuration and restrict access to the user interface to prevent even knowledgeable users from making changes. The information about locked and hidden configurations is saved on a central location. An administrator can remotely remove the locks to permit users to modify this configuration.

Administrators can use this capability to prevent users from installing certain components, to set usage policies centrally, and to define a “safe” configuration for Windows 95 in the event that a user inadvertently alters a desktop configuration.

Network Server Access

Windows 95 includes the software required to connect to most popular network servers, including Novell® NetWare® 2.x, 3.x, and 4.x, Windows NT Server, LAN Manager, LAN Manager for UNIX®, IBM® LanServer, 3Com® 3+Open® and 3+Share®. Additional networks are as easy to install as additional printers.

If you already have a network server, Windows 95 can continue to use your current networking software. You can upgrade to the high-performance components included with Windows 95. In addition, if you have multiple network servers, Windows 95 provides simultaneous connections with a choice of popular protocols, including IPX/SPX, TCP/IP, and NetBEUI.

Deferred Printing

Another feature that can make working away from the corporate network more convenient is deferred printing. A user not connected can print just as if there was access to the network printer in his office. Windows 95 print spooler places the print job into the queue, and automatically sends the print job to the printer when the user reconnects to the corporate network.

File Synchronization

Windows 95 file synchronization services are optimized for the needs of the mobile computer user who wants to take copies of documents to a remote location and have them be automatically synchronized with the source documents. It features a very intuitive user interface that uses a briefcase icon as the metaphor for performing file synchronization operations.

Resource Management Improvements

Both Win16 and Win32-based applications use the same GDI and USER heaps. The impact of removing selected items from the heaps was closely examined and objects were selected based on the biggest improvement that could be achieved, while affecting the fewest number of applications. For example, the GDI heap can quickly become full due to the creation of memory-intensive region objects used by applications for creating complex images and by the printing subsystem for generating complex output. Regions have been removed from the 64K 16-bit GDI heap and placed into a 32-bit heap. Graphic-intensive applications benefit greatly from this improvement. Windows 95 improves the system capacity for the USER heap by moving menu and window handles to the 32-bit USER heap. Raising the total limit of these data structures from 200 in Windows 3.1, to a total limit now of 32,767 menu handles and an additional 32,767 window handles per process rather than system wide.

The Registry--Centralized Configuration Store

Windows 95 uses a mechanism, called the Registry, that serves as the central configuration store for user, application, and computer-specific information. The Registry solves problems associated with .INI files as used in Windows 3.1, and is a hierarchical database that stores system-wide information in a single location, making it easy to manage and support. The need for CONFIG.SYS and AUTOEXEC.BAT goes away since those contents are now managed by the registry.

Support for Win16-based Applications

16-bit Windows-based applications (Win16) run together within a unified address space, and are run in a cooperatively multitasking fashion similar to Windows 3.1. Win16-based applications benefit from the preemptive multitasking of other system components including the 32-bit print and communications subsystem, and the improvements made in system robustness and protection from the Windows 95 system kernel.

Support for MS-DOS-Based Applications

There are many improvements in Windows 95 for running MS-DOS-based applications over Windows 3.1. Similar to Windows 3.1, each MS-DOS-based application runs in its own “virtual machine” (VM). A VM takes advantage of the Intel 80386 (and higher) architecture allowing multiple 8086-compatible sessions to run on the CPU, allowing existing MS-DOS applications to run preemptively with the rest of the system. As with Windows 3.1, the use of virtual device drivers provide common regulated access to hardware resources, thereby making each application running in a virtual machine think it’s running on its own individual computer. This allows applications not designed to multitask the ability to run concurrently with other applications.

Protection

The support for running Win16-based applications provides protection of the system from other running MS-DOS-based applications or Win32-based applications. Unlike Windows 3.1, an errant Win16-based application can not easily bring down the system or other running processes on the system. While Win32-based applications benefit the most from system memory protection, the robustness improvements present in Windows 95 result in a more stable and reliable operating environment than Windows 3.1.

Long Filename Support

Win32-based applications that call the file I/O functions supported by the Win32 API will benefit from the ability to support and manipulate filenames up to 255 characters. The Win32 APIs and common dialog support handles the work for manipulating long filenames, and the file system provides compatibility with MS-DOS and other systems by also maintaining the traditional 8.3 filename automatically. This eases the burden from the application developer.

Open Architecture for Open Connectivity (Info Center)

The Info Center is designed to work with virtually any messaging or workgroup system—whether it’s LAN-based, host-based, or an online service requiring dial-in access. The key to this open architecture is MAPI—sometimes called the “Windows Messaging System.”

The figure above provides a simple view of the architecture for the Info Center.

Any information or messaging service provider can develop a MAPI “driver” so that the Info Center can be used with their system. There are several organization writing drivers to support this function within Windows 95.

Graphical User Interface (GUI)

When first booting Windows 95, it is immediately apparent that the old world of Windows running on top of MS-DOS is no more. Gone are the character-mode boot messages that held meaning for a very small minority of computer users. Instead, you are graphically carried to the desktop of the new Windows 95 user interface (UI).

In order to do the GUI justice, several pages would need to be written. I suggest that you refer to the Technet CD and do a search on “Chicago, user interface.” Look for “Chicago Product Overview.” That article covers the Windows 95 GUI in great detail.

Disadvantages

Windows 95 provides the computer industry with the next generation operating system. With the relatively young age of the OS, one can expect a few disadvantages to be uncovered. The disadvantages are not associated with the OS architecture itself rather cost and availability of applications. Listed below are the disadvantages associated with a migration to Windows 95:

• Cost to upgrade/Just migrated to WFW
• Hardware requirements too high
• Do not see the value of 32 bit applications

As you have gathered from the above information, Windows 95 is a very powerful OS which requires proper hardware as well as software in order to achieve the best performance. Organizations that have chosen to implement the Windows 95 platform over WFW or NTW have done so for the following reasons:

• Need 32 bit applications performance
• Requires performance of 32 bit OS
• Remote management is important
• Must run 16/32 bit applications
• Employees on the road who require a powerful OS that has low demands on disk space, memory requirements and battery usage

Platform Architecture

Windows NT is a modular operating system. It is a collection of relatively small, self-contained software components (or modules) that work together to perform operating system tasks. Each component provides a set of functions that act as an interface to the rest of the system. Components can call each others’ functions to get work done.

The figure below shows some of more important Windows NT components and the relationships between them. The responsibilities of these components are described briefly here:

• Environment Subsystems run programs written for several different operating systems as well as Windows NT. Examples are the Win32 subsystem, OS/2 subsystem, and POSIX subsystem.
• NT Executive is the kernel-mode portion of Windows NT. Does most of the I/O and object management, including security. Does not do screen and keyboard I/O, which is done by the Win32 subsystem.
• Managers are modules of the NT Executive that manage I/O, Objects, Security, Inter-process communications (IPC), Virtual Memory, and Processes.
• Device Drivers are modules which translate their calls into hardware accesses.
• Kernel manages processor only--more like a microkernel.
• Hardware Abstraction Layer virtualizes hardware interfaces, making Windows NT more portable.

Platform Hardware Requirements

The hardware requirements for NTW 3.5 are as follow:

• Disk: 40MB
• Memory: 16MB
• Processor: Intel 486 or RISC

Portability

Windows NT currently runs on Intel 80386, 80486, Pentium, MIPS R4000, and DEC Alpha processors. This is a noteworthy acczomplishment given the considerable differences between the instruction sets of these processors. The MIPS and DEC processors are reduced instruction set computers (RISC). This means that they support a small number of instructions, each of which performs a relatively simple operation. In contrast, the Intel processors are complex instruction set computers (CISC). That is, they support a larger set of more complex instructions. It is expected that Windows NT will be ported to other processors in the future.

Symmetric Multiprocessing

Windows NT supports symmetric multiprocessing (SMP). This means it can run on systems that have multiple processors, and utilize all processors to run both operating system and application code. Multiple-processor computers are commonly used as high-end server platforms, hosts for multi-user interactive sessions, and single-user systems running resource intensive desktop applications.

Performance

Windows NT is a fully 32-bit operating system. This means that its components execute instructions that manipulate 32-bits of data at a time. In contrast, key components of Windows 3.1 for MS-DOS are limited to instructions that manipulate only 16-bits of data at a time. The 32-bit advantage allows certain types of operating system and application code to run much faster on Windows NT.

Extensibility

The Windows NT operating system is designed to allow extensions to be added over time. For example, Windows NT can be extended add support for new:

• Application support subsystems: Currently Windows NT can run applications written to 5 different application programming interfaces (MS-DOS, Windows 3.1, OS/2 1.x , POSIX, Win32). Windows NT is designed to allow addition of new “subsystems” that could potentially provide support for additional application types.
• Device drivers: Device drivers can be dynamically loaded and unloaded in Windows NT, so it is easy to add new device drivers and update existing ones.
• File systems: File systems are implemented as drivers in Windows NT, so addition of new file systems is as easy as loading a new driver.
• Network client capabilities: Network vendors are provided with a standard method for writing software components that will allow Windows NT workstations to act as clients on their networks.

Windows NT Workstation includes high-performance 3-D graphics capabilities with the OpenG™2 API as a native part of the operating system. OpenGL is an operating system independent, industry standard library of graphics functions originally developed by Silicon Graphics. OpenGL is now defined by an Architecture Review Board consisting of Digital Equipment Corporation®, IBM, Intel, Microsoft, and Silicon Graphics®. Microsoft has licensed this technology from Silicon Graphics in order to provide these powerful 32-bit APIs for users of Windows NT Workstation.

These advanced graphics capabilities are needed when visualization of large designs and data is important. Typical situations where 3-D graphics might be required include CAD/CAM applications; industrial, interior and mechanical design applications; and statistical and scientific analysis products. OpenGL technology has also been used to provide some of the special effects used by movie producers in recent films such as Jurassic Park and Terminator 2.

Multiple VDM support

Windows NT Workstation allows preemptive multitasking of 16-bit applications for Windows and MS-DOS with full memory protection. Each application runs in its own memory address space. The result is increased application responsiveness and maximum data/application protection. Full OLE and DDE support are maintained between separate VDMs.

OLE 2.0 support

OLE 2.0 allows in-place editing, application automation, drag-and-drop between applications, and full integration and information sharing. Windows NT Workstation provides 16- to 32-bit OLE support.

Integrated NetWare Connectivity

A full NetWare-compatible client redirector is included for fast, easy connectivity to NetWare and Windows NT Servers using the IPX/SPX transport.

New TCP/IP Transport Plus PPP and SLIP

The TCP/IP stack is now faster and smaller; our tests show a 100% increase in performance. Point-to-Point Protocol (PPP) and Serial Line Internet Protocol (SLIP) are two standard protocols enabling TCP/IP over asynchronous lines. These protocols are important to the UNIX and Internet communities.

Enhanced Network Connectivity

Connectivity products for NFS, Banyan®, and X-Windows have been released from a variety of third parties.

Dump Facility with Auto-Restart

If the workstation experiences a fatal error, memory registers are written to disk and the system can be automatically restarted.

Long Filenames for FAT File System

File and directory names on the File Allocation Table (FAT) file system are no longer restricted to the 8.3 naming convention. Instead, file and directory naming rules are similar to those of NTFS: names can be up to 255 characters, with support for upper and lower case.

Enhanced Hardware Compatibility

Windows NT has been tested on over 2300 Intel®-based systems, 37 MIPS®-based systems, four Alpha AXP™ systems and 15 SMP systems, as well as with many tape drives, SCSI devices, network cards, etc.

Disadvantages

The disadvantages associated with NT Workstation are not associated with the operating system itself. Feedback from organizations has been:

• Hardware requirements: NTW as a workstation requires a large amount of disk space and memory. Considering the power of the OS, its hardware requirements are not out of the ordinary. However, at first glance, if one is upgrading from Windows which requires one fifth the disk space and half the memory it is a difficult requirement to oversee.
• Graphical user interface: The graphical user interface for NTW is Windows. Though it works well, at this time it is a disadvantage for the product. It is forecasted that the next release will deliver the new GUI.
• 32 bit applications: There are a small number of 32-bit application in the market. However, we are seeing a larger number being released on a monthly basis.

Windows NT Workstation is the most powerful desktop operating system targeted for the most demanding business needs. It is a true 32-bit, multitasking operating system that lets users take full advantage of widely available high-end applications for software development, engineering, financial analysis, scientific, and business-critical tasks, while continuing to run the thousands of standard Windows applications. It also provides the highest degree of protection for critical business applications and their data while providing a complete security system for desktop computers. It preserves users’ technology investments today, while providing the foundation to build on for tomorrow.

Four major types of customers will be able to immediately benefit from the adoption of Windows NT Workstation:

• Developers: Using development tools available from both Microsoft and third parties, Windows NT Workstation makes an excellent development platform for both Win16 and Win32 applications targeted for either Windows NT Workstation or the upcoming Windows 95 product.
• Technical users including engineers, scientific users, statisticians, and others: With the performance it offers, these users will find Windows NT Workstation a natural fit. A number of key applications are available for these users in vertical segments such as mechanical design automation, electronic design automation, medical, architectural, engineering and construction, manufacturing and process control, and geographical information systems. Originally, many of these applications ran on UNIX workstations, but have now been ported to the Windows NT platform.
• Financial workstation users: These users include securities traders, mortgage bankers, accountants, and others. Windows NT provides the extra reliability and security they need to keep data that these users depend on confidential.
• Business-critical application users: This final category addresses the requirements of users who require the power and protection of Windows NT Workstation, which Windows 95 will not address: security, robustness, manageability, high capacity and performance (symmetric multiprocessing, or SMP), hardware independence, and high concurrency.

Below you will find all the features and which operating system provides them.