The evolution of personal computing and the evolution of DOS are tightly interwoven. As the original operating system for the IBM PC, DOS was the first and only operating system used by millions of computer users. Introduced more than a decade ago, DOS has become a familiar and popular interface. According to International Data Corporation (IDC), DOS continues to command the largest installed base of any software product in history--with well over 100 million users.
As the processing power of personal computers has increased, more complex and powerful operating systems have been introduced. These operating systems were expected to encroach on the DOS installed base. Yet DOS sales have remained strong. The percentage of UNIX and OS/2 shipments is increasing gradually. For the most part, however, this growth is occurring at the expense of proprietary systems. According to the Gartner Group, DOS will account for 70 percent of 1993 estimated personal computer shipments. MS Windows, which runs on top of DOS, accounts for about one half of this estimate.
Figure 1--1993 Estimated Computer Shipments
Throughout the past decade, DOS has had to evolve to keep pace with new hardware. Digital Research dramatically accelerated the technological evolution of DOS in 1990 with the introduction of DR DOS 5.0. DR DOS provided users features which enabled them to exploit the computing hardware on the desktop. Since that time, the two leading DOS suppliers, Novell and Microsoft*, have incorporated many new features that help users leverage their investment in desktop computing. Dozens of software companies have developed innovative utilities and add-on products that enhance the DOS environment and make it easier to use. Most importantly, DOS supports over 30,000 applications, spanning a wide range of industries.
DOS represents a huge installed base of users who find that this operating system meets their computing needs. Many organizations have a significant investment in DOS software--applications, utilities and development tools--and in DOS training. As a result, these organizations are not motivated to incur the cost of moving to a new operating system, developing and implementing new applications, enhancing hardware, and retraining users. These organizations are constantly seeking to extend the capabilities of DOS to help them boost performance and enhance the productivity of their personal computer users. As a result, new versions of DOS that offer technology advancements have met with wide user acceptance.
The power and performance of DOS is also important to MS Windows users because MS Windows runs on top of the environment created by DOS. The functionality and performance of the underlying operating system directly impacts the performance of MS Windows. As a result, MS Windows users continue to demand "a better DOS" as a foundation for their MS Windows environment.
The Growing Requirement for Networking
During the past decade, DOS technology enhancements have focused on delivering higher performance and increased personal productivity. With the proliferation of local area networks (LANs) in the 1990s, however, DOS users are now turning their attention to networking. The dominant trend of the 1990s is the interconnection of information resources into distributed, enterprise information systems, or networks. Networking enables users to communicate, share information and access expensive resources and peripherals. Networks add value to the organization by supporting the collaborative process.
As the leader in PC networking, Novell is keenly aware of the major role networks play in the computing systems of the 1990s. NetWare has become the standard for enterprise computing by providing an infrastructure that serves a variety of client systems and provides connectivity to existing host systems and to a multitude of other networking services. The ability to access a managed and manageable network enables the collaborative process. This is the value that NetWare brings to its customers.
Novell's goal is to develop a computer network that, like the telephone network, provides a wide range of services while remaining transparent to users. Toward that goal, Novell is evolving an integrated network computing architecture based on NetWare. Novell's client operating systems, Novell DOS 7 and UnixWare, are critical components of that architecture. As a result, network integration is a critical requirement for these systems. By providing the most advanced client operating systems with the highest level of network support and integration, Novell provides the foundation for the computing systems of the 1990s.
As the power of personal computer hardware continues to increase, users will continue to demand a better DOS--one that meets their growing demands, while continuing to support their current solutions. Networking must play an important role in the future of DOS technology.
This paper describes Novell's latest DOS release, Novell DOS 7, and the role it plays in advancing the DOS standard and integrating DOS into the networked environment. This integration enables DOS to support the collaborative process, which brings added value to NetWare.
Evolution of DOS
To better understand the real benefits of Novell DOS 7, the latest generation of DOS, it is useful to examine the evolution of DOS. Earlier generations are distinguished by the major areas of functional improvements they provided to address the requirements of their times.
Figure 2--Generations of DOS
The continuing evolution of DOS has enabled personal computer users to maximize their investment in computing hardware and software. The next major step is tight integration of networking with the operating system.
DOS 3.0--File Sharing
We will begin with the third generation of DOS. MS-DOS 3.1 was the first version of DOS to provide system-level support for shared file access. This was in response to requirements generated by the emergence of personal computer networks. Hand in hand with file sharing were other significant improvements. Version 3 raised the maximum disk partition limit from 20 Mb to 32 Mb to support larger hard disks than previous releases. Version 3.3 allowed multiple 32 Mb partitions and Compaq's proprietary version 3.31 increased the partition size to 512 Mb. DR DOS version 3.31 from Digital Research, released in 1988, provided Compaq DOS 3.31 compatibility.
DOS 5.0--Memory Management
The fourth generation of DOS is most notable for making support for larger hard disks (introduced by Compaq in DOS 3.31) more widely available. Because DOS 4.0 offered no other major enhancements, our discussion moves forward to the fifth generation. In 1990, DR DOS 5.0 from Digital Research set the standard by incorporating an interactive installation program and integrated memory management. These new features represented a significant advance in DOS technology. With this product, Digital Research created a new retail end-user market for DOS. Customers began to purchase DR DOS 5.0 as an upgrade to the DOS that came installed on their computers. Microsoft followed the lead of Digital Research in 1991 by introducing similar features in MS-DOS 5.0.
The fifth generation of DOS distinguished itself from previous versions by enabling the operating system to use memory management. This key enhancement solved a major problem facing personal computer users. Because applications had grown significantly in size, and device and network drivers and TSR utilities were becoming a larger part of the DOS user's environment, they had to compete for the first 640 Kb of RAM, called "conventional" memory. There simply was not enough space for all of them to reside in conventional memory along with the operating system. This restricted application functionality and limited the user's ability to take advantage of new drivers and utilities.
With DR DOS 5.0, personal computer users were able to use supporting hardware on 8086, 80286 or the memory paging capabilities of the 80386 microprocessor to relocate device drivers, TSRs and portions of the operating system outside of the first 640 Kb. This freed a considerable amount of conventional memory, making it available for larger, more sophisticated application programs. Memory management was of particular importance to networked computers because of the memory required for network device drivers and TSRs. These drivers and TSRs could now be located in "upper memory" between 640 Kb and 1 Mb. This freed up conventional memory allowing larger application programs to run in the networked environment.
DOS 6.0--Disk Management
As application programs grew in sophistication, they became larger in size, requiring not only additional RAM, but also increased hard disk capacity. In addition, as users became more sophisticated they began to use more applications and utilities, further increasing the need to maximize available hard disk storage.
The introduction of MS Windows intensified the need for additional disk capacity. MS Windows itself requires additional hard disk space, and MS Windows applications are significantly larger than their DOS counterparts.
The growing popularity of laptop and notebook computers presented personal computer users with another problem. Users needed additional hard disk capacity to store their applications, TSRs and utilities. Laptops and notebook computers, however, had a limited amount of disk capacity available.
The sixth generation of DOS solved these two problems by integrating disk management utilities. DR DOS 6.0, launched in 1991, was the first DOS to include dynamic disk compression that effectively doubled the available space of hard disks. With disk compression, personal computer users could take advantage of larger DOS and MS Windows applications without the expense of adding hard disk capacity; and laptop and notebook computer users were no longer constrained by insufficient disk space. Additional utilities provided file recovery for safety, and defragmentation for improved disk performance. MS-DOS 6.0, which shipped in March 1993, also included a disk compression utility as its primary feature.
Novell DOS 7--Extending the Lead
As DR DOS set the standard for the fifth and sixth generations of DOS, Novell continues to lead the way with Novell DOS 7. The features incorporated into Novell DOS 7, and the benefits they provide its users, will ensure that DOS remains a viable and highly functional environment for years to come.
One of the major capabilities of Novell DOS 7 is the integration of networking into the product itself. This networking capability meets the needs of existing NetWare users and PC users who are becoming networked for the first time. Novell DOS 7 also advances the standard for DOS with multitasking and protected mode extensions, while maintaining full compatibility with the vast installed base of DOS and MS Windows applications. The technology enhancements in Novell DOS 7 deliver faster performance and greater power for personal computer users.
Novell DOS 7 Enhancements and New Technologies
This section describes the major DOS technology advancements of Novell DOS 7. These include memory management enhancements, multitasking, and improvements in disk management, performance and safety. Novell DOS 7 also enhances workstation security to allow it to be configurable per user, defining access rights to various resources during specified hours. These improvements are described in more detail in the remainder of this section.
In addition to these DOS enhancements is the integration of networking with DOS. Networking enhancements are described in the "Novell DOS 7 Networking Enhancements" section.
DOS Protected Mode Services
As discussed earlier, the memory management capabilities introduced in DOS 5 solved a major problem. It enabled users to free conventional memory by moving drivers, TSRs and portions of the operating system into upper and high memory. Yet memory constraints have continued to be a concern for personal computer users. While DOS 5 provided over 620 Kb of application memory, utilities soon began to eat up that memory. For example, DOS disk compression utilities use up 40 to 50 Kb of memory.
Figure 3--DOS Protected Mode Services API
The DPMS API allows device drivers and TSRs to reside in extended memory and execute in protected mode on 286, 386, 486 computers. This frees conventional memory for larger application programs.
Novell DOS 7 addresses this problem with the DOS Protected Mode Services (DPMS) API. This API enables developers to create device drivers, TSRs and other system extensions that can take advantage of protected mode to reside in and execute from extended memory. The result is a feature-rich environment in which users can take advantage of multiple drivers and utilities, and still have enough room for very large applications. DPMS drivers can run in conventional memory on 8086 machines allowing developers to cater to the whole market with one driver.
Novell DOS 7 includes disk cache, disk compression, Desktop Server and CD-ROM extensions that take advantage of DPMS and use very little conventional or upper memory. As a result, users can benefit from these advanced utilities and still retain enough memory for even the largest DOS applications--without disabling any of their system extensions.
DPMS is not tied to Novell DOS 7 or other Novell DOS products. It is compatible with other versions of DOS, including previous versions of DR DOS and MS-DOS. DPMS is fully compatible with MS Windows in all of its operating modes, and users benefit from having more memory for their DOS sessions with DPMS. Novell has released the DPMS specification to the industry to allow third-party vendors to produce their own DPMS programs and distribute them free of royalty charges.
Multitasking
For most users the personal computer has become a multi-purpose business tool, enabling them to generate documents, spreadsheets and business presentations, as well as send mail and access data stored on other computers. Most users have several application programs they use regularly--and they find they must switch from one program to another, for example, interrupting work on a spreadsheet to send an electronic mail message or to print a word processing document. Multitasking is an important, productivity-enhancing feature that enables users to load and run more than one application at a time. Users can switch quickly and easily among applications, without quitting one application and loading another.
Novell DOS 7 provides a highly efficient, pre-emptive multitasking scheme that allows users to run several DOS programs simultaneously, without the resource overhead typically associated with these environments. With a pre-emptive kernel, a running task can be interrupted by a higher priority task, thereby allowing the most efficient use of processing resources. Novell DOS 7 multitasking supports existing DOS applications--that is, users are not required to purchase special "multitasking" applications to take advantage of this capability.
The multitasker offers extensive multitasking support. Unlike some other environments that offer multitasking, the Novell DOS 7 multitasker does not suspend graphics applications when they are switched into the background. Graphics programs continue to run--for example, printing in the background--to ensure high levels of productivity for users. The multitasker supports multiple extended DOS applications and MS Windows. The multitasking API provides functions for shared memory, inter-process communications through pipes, queues and semaphores, and program execution control.
Novell DOS 7 multitasking increases hardware utilization by allowing the computer to continue processing one job while the user moves on to another. And it allows developers to use Novell DOS 7 as a platform for numerous application areas that require multitasking. These include monitoring and process control environments.
Extended Functionality and Ease of Use
Traditionally, only the more technically sophisticated users have been able to take advantage of such utilities as disk compression and optimization, disk caching and memory management. This is because these utilities had to be purchased and installed separately, and many users found them difficult to use. Novell DOS 7 integrates an extensive set of DOS utilities with the operating system. Installing and using them is greatly simplified, and operation is easy because the utilities use a common interface. As a result, all levels of users--from the novice to the most advanced--can take advantage of the enhanced performance that these utilities provide.
Novell has greatly enhanced the user documentation included with Novell DOS 7. On-line documentation with hypertext links provides a quick and easy reference to answer users' questions. The printed documentation offers a clear and concise guide to general computing concepts.
Ease of use and end user choice have been enhanced with the provision of both full screen DOS and MS Windows versions of the advanced utilities supplied with Novell DOS 7. This allows the end user to remain within their preferred environment when using these features.
Disk Performance and Management
Novell DOS 7 includes advanced disk utilities that increase disk capacity and enhance performance. It includes fully integrated disk compression software to double the usable capacity of both hard drives and removable media, such as floppy disks.
Advanced disk caching, disk optimization, and undelete are included to enhance disk performance and protect data from accidental deletion. The system extensions for disk caching and compression use DPMS to minimize their use of application memory.
Data Security
Because of the critical nature of data stored on personal computers and LANs, protecting that data is a major concern of personal computer users. To satisfy the need for data security, Novell DOS 7 includes Fifth Generation's industry-leading utilities for backup and virus protection. FastBack Express and Search & Destroy are included in both DOS and MS Windows versions ensuring ease of use in both of these environments.
Microsoft Windows Support
Novell DOS 7 fully supports MS Windows and, in fact, offers a better foundation for the MS Windows environment than does MS-DOS 6.0. The MS Windows versions of FastBack Express (the integrated backup utility) and Search & Destroy (the built-in anti-virus utility) enable users to back up files and run virus scans using familiar MS Windows operations. The networking utilities, discussed in the following section, also employ the MS Windows interface to ease network administration and workgroup management, ensure consistency and minimize training for MS Windows users.
Novell DOS 7 disk compression is proving invaluable for MS Windows users who need to maximize their hard disk capacity to make room for MS Windows applications, which are significantly larger than their DOS counterparts. In addition, by maximizing the amount of free upper and conventional memory through DPMS, Novell DOS 7 allows MS Windows to run optimally in a feature-rich environment.
CD-ROM Extensions
CD-ROM drives are quickly gaining a place on many PCs. As users increase their usage of multimedia applications that include graphics, photographs and video, CD-ROM drives will become a requirement. To support user needs for CD-ROM, Novell DOS 7 has incorporated an MSCDEX 2.2 compatible redirector that provides access to CD-ROM media. Unlike MSCDEX, the CD-ROM redirector uses DPMS, leaving more conventional memory available for applications.
Configuration
Novell DOS 7 enhances CONFIG.SYS and batch file processing to make system configurations more flexible. Prompt statements, conditional commands, and menuing enable users to support multiple boot-time and run-time scenarios within a single configuration or batch file.
Novell DOS 7 Networking Enhancements
As previously discussed, Novell is evolving an integrated network computing architecture based on NetWare, and Novell DOS 7 is a critical component of that architecture. As a result, Novell DOS 7 includes a number of enhanced networking capabilities.
Integrated Networking
Novell DOS 7 is the first DOS that fully integrates desktop networking. Novell believes that integrated networking will be the major feature that defines the seventh generation of DOS. By incorporating networking functionality, Novell DOS 7 provides customers a fully functional, highly integrated desktop networking environment.
Novell DOS 7 provides peer-to-peer services, which allow it to share workgroup resources with other computers running Novell's Desktop Server, the built-in peer-to-peer network "server" capability. This makes networking accessible to the emerging class of first-time network users, and cost-conscious workgroups. Novell DOS 7 addresses their needs with a simple, yet reliable and efficient solution. It is also the best DOS client operating system for NetWare with the latest client technology for access to all NetWare and Desktop Servers.
Figure 4--Resource Sharing for Workgroups
Novell DOS 7 offers built-in peer-to-peer networking, giving small organizations and workgroups within larger organizations a simple, low-cost networking solution.
Desktop Server
As the advantages of networking become more widely known, many small businesses are entering the network computing market. Many of these newcomers have little or no experience in network computing technology. The Novell Desktop Server offers these users a means of sharing data and resources on a peer-to-peer basis, without the need for traditional dedicated file servers. Any user on the network can share files, printers and other resources with any other user. With the incorporation of the Desktop Server, Novell DOS 7 is an easy-to-use, yet robust and reliable desktop network operating system that is ideal for workgroups or first-time network users.
Peer-to-peer networking is also an excellent low-cost solution for workgroups within a larger NetWare environment. With the Desktop Server, organizations can offer small workgroups the flexibility and control of peer-to-peer networking while still permitting access to NetWare services when they are required. The Desktop Server is fully integrated with the NetWare environment. It uses the same network drivers, network interface cards, transports and client utilities as NetWare, so it is fully compatible and manageable within the organization's existing network.
Novell plans to extend desktop networking by implementing the Desktop Server on a variety of client operating systems. This will allow all clients access to workgroup resources, regardless of the operating system or hardware platform. The Novell DOS 7 Desktop Server is the first step towards a heterogeneous peer networking environment.
NetWare Universal Client
The NetWare Universal Client is a network redirector that allows Novell DOS 7 to access resources on any NetWare 2.x, 3.x and 4.0 file server, or any computer running Novell's Desktop Server. This permits users to access enterprise-wide as well as workgroup resources through a single common interface. As a result, users interact with the network--for example, mapping files and drives--in the same manner, whether they are accessing resources within a peer-to-peer network or a more traditional NetWare server.
Network Management
In any environment that allows resources to be shared, those resources must be managed for security and efficiency. Thus network management is a major concern for MIS managers and system administrators. Novell DOS 7 includes an industry standard SNMP agent, Management Information Base (MIB) and diagnostic responder. These allow Novell DOS 7 workstations to be easily identified and administered from remote locations. Built-in SNMP network management ensures that Novell DOS 7 computers are manageable within an enterprise by a variety of Novell or third party management consoles. For ease of use, all Novell DOS 7 network management utilities can be accessed through a full-screen DOS or MS Windows interface.
Security
In both standalone PC environments and network environments, protecting sensitive information from unauthorized access is essential. Novell DOS 7 extends the built-in security features of DR DOS 6.0 to provide a NetWare compatible security model. It includes secure disk partitions as well as file and directory passwords. Novell DOS 7 security allows the owner or system administrator to limit user access to specified hours and restrict access to floppy drives, parallel and serial ports. The security enhancements also support one-time login, where access to both the PC and the network is protected by a single password.
Network Installation and Configuration
Novell DOS 7 includes a network installation and configuration capability that eliminates the need for an administrator to go to each personal computer in the network to install or upgrade the operating system software and configure it to meet network requirements. Network installation dramatically reduces the time and effort previously required to install and administer networks of all sizes. And it provides centralized control. Because installation and configuration are completely transparent, the end user can enjoy all the new features of Novell DOS 7 without any additional effort on their part.
Network installation and configuration gives organizations greater control of the network and the end-user computing environment. The system administrator can fine tune the various operating system features to control how users access and use them. In addition, the system administrator can prevent access to any features that the organization does not want deployed. For example, the system administrator can disable peer-to-peer networking or disk compression so that selected users cannot use this capability.
Summary
Novell DOS 7 includes a number of major enhancements to DOS including integrated NetWare client support, peer-to-peer networking, a network management agent, network installation and configuration, pre-emptive multitasking, enhanced memory management, enhanced desktop security and a suite of protected mode drivers. As a result, Novell DOS 7 will appeal to a wide variety of DOS users, including:
t Users who need additional operating system capability to exploit the power of their desktop hardware
t First-time network users
t Experienced Novell NetWare users
Novell DOS 7 represents Novell's commitment to provide responsible leadership to both the DOS and the network industries. Once again, Novell has created the most advanced DOS, which will provide the benchmark for future versions while allowing users to preserve their investments in application software and hardware.
