comparing the SAS System under OS/2 and Microsoft Windows

Which is right for you?

Abstract

Mark W. Cates

SAS Institute Inc.

As we enter into the 1990s, two operating systems are available to enhance productivity for cEersonalcomput­ers and provide a future platform for PC software users. The two environments, OS/2 • version 1.3 and Microsoft Windows ® 3.0 provide fundamentally the same user interface and similar features, but the underly­ing operating systems are radically different. Today, corporations large and small are deciding which operat­ing system should be used in their organizations and for which applications. The platform for more powerful and mission critical applications is clearly OS/2. However, with the introduction and overwhelming accep­tance of Windows 3.0, supporting DOS compatibility, a graphical user interface compatible with Presentation Manager, and access to extended and virtual memory, a large memory alternative to OS/2 is available. This paper discusses these two environments with respect to the SAS System. The paper presents the advantages and disadvantages of the operating systems, configuration issues, and future directions, with respect to the SAS System. Issues that are particularly important to the SAS System are described in detail. Finally, the implications of the new 32 bit OS/2 version 2.0 are presented. (In this paper, Microsoft Windows 3.0 will be referred to as an operating system. Actual~, Microsoft Windows is a layered operating environment that runs on top of the operating system PC DOS •. For purposes of this paper, the distinction between operating environment and operating system is not important.)

SAS release status for OS/2 and Windows

Version 6.06 of the SAS System has been in production for OS/2 1.2 and 1.3 Standard and Extended Edition, as well as Microsoft's OEM versions since November 1990. It supports all SAS version 6.06 products and procedures including SAS/ACCESS, SAS/AF, SAS/ASSIST, SAS/BASE, SAS/CONNECT, SAS/ETS, SAS/ FSP, SAS/IML, SAS/GRAPH, SAS/OR, SAS/STAT, and SAS/QC.

At SUGI15 in Nashville (March 1990), the Institute announced the planned support for Microsoft Windows version 3.0, starting with the SAS System version 6.07 .. This release is planned for late 1991. Simultaneously, version 6.07 will be released on OS/2 version 1.3. The Institute is committed to both of these operating environments and believe that each environment is strategic to corporations, and thus will provide support for them with future SAS releases. The products released on each environment will be the same. The feature set of the procedures will be identical; the only difference in the releases will be advanced features that one environment may support that the other does not. The SAS catalog file format and the data set file format will be byte for byte identical across the two systems. SAS data sets and catalogs will be easily and immediate­ly transferrable between the two operating systems by merely using the copy command. Every attempt will be made to support upgrades of the operating system such as Windows 3.1 and upgrades to OS/2 version 1.3. Complete hardware and software requirements for both systems can be obtained by calling Software Sales at the Institute.

Comparing OS/2 and Windows with respect to the SAS System

Memory management

OS/2 version 1.x supports the architectural functions of the Intel 80286 processor which includes accessing up to 16 Meg of physical extended memory, and up to 1 Gigabyte of virtual memory used for segment swapping. OS/2 1.x executes faster on a 80386 or 80486 processor due to the increased processing power but does not take advantage of 32 bit processing or the advanced memory management facilities of the 80386. OS/2 is supported on a 80286 machine, but SAS performance on this processor is obviously marginal. For

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OS/2 1.2 and 1.3, the SAS System version 6.06 recommends a minimum of 6 Meg of memory and 8 Meg for optimum performance of large applications like SAS/ASSIST and SAS/GRAPH. It Is important to note that problems are only limited by the amount of disk swap space and that adding additional extended memory will normally increase the limits of the system. Unlike SASPC DOS versions using Expanded Memory (EMS), the SAS System may take advantage of all additional extended memory for both executable code and program data. The increased memory available to applications is a substantial benefit provided by OS/2. Compared to PC DOS execution, the SAS System executes faster under OS/2. Although this is contrary to some reports concerning performance comparisons between PC DOS and OS/2, it holds true for SAS because of the performance loss SAS suffered on PC DOS. Under OS/2, SAS does not have to resort to disk intensive code overlays and costly unloading and loading of executable images. Additionally, the code generator that is used to execute data step and procedure code has been improved and optimized for the OS/2 environment.

Windows 3.0 runs in three modes: Real mode, Standard mode, and Enhanced mode. Real mode is the native mode of the original IBM PC using an Intel 8088 microprocessor. Original versions of Windows ran in real mode as does PC DOS, and is provided primarily for compatibility of older Window applications. SAS under Windows does not and will not support real mode in any future release, since real mode limits the application to 1 Meg of memory.

In Standard mode, Windows requires at least an Intel 80286 with at least 1 Meg of memory, or a 80386 with less than 2 Meg of memory. In this mode, Windows runs in protected mode which means the processor can address up to a maximum of 16 Meg of extended memory if available. Standard mode, however, is limited to the physical available memory. Once this memory is used by applications, Windows memory management will move and discard program segments to attempt to manage the memory. However, swapping. of seg­ments to disk to obtain virtual memory is not performed in standard mode. Therefore, adding more extended memory up to a maximum of 16 Meg is necessary to increase performance and overcome memory limitations for an application like SAS. Standard mode allows an application to execute faster than Enhanced mode because it does not rely on slower virtual device drivers that Window~,uses in enhanced mode.

Enhanced mode requires an Intel 80386 or 80486 processor and at least 2 Meg of .extended memory. This is the most optimal mode for Windows and for power users. In this mode, the processor can once again access up to a maximum of 16 Meg of extended memory. However, Windows memory management takes advantage of the 80386 memory management paging features to "page" in and out 4 k byte blocks. When physical memory has been filled, the paging process begins. Only when all the virtual address space on disk has been used, does Windows discard program segments. (Discarded program segments are required to be reloaded and relocated, and thus discarding is slower than paging.) Enhanced mode can be misleading, especially to power users. A little published fact about Windows enhanced mode is that the virtual paged memory Is limited to approximately four times the amount of physical memory. This is a system limit, not a per task limit. For example, on a machine with 4 Meg of memory, Windows enhanced mode will provide the entire system including all applications running, with an address space up to 16 Meg (4 x 4) of memory, assuming that this amount of disk space is available in either the temporary or permanent swap file. This fact can easily dispell the belief that Windows virtual memory provides the same function and benefit that OS/2 does, just because both run in protected mode. The reason Windows limits the paging to four times physical memory is to prevent a large portion of the physical memory from being used by in-memory page tables. Another advantage of enhanced mode is that Windows uses .the virtual 86 mode of the 80386 processor to allow multiple DOS sessions to run in windows concurrently. This feature is more important for DOS programs. However, running multiple DOS shells can cause instability In DOS because DOS Is not reentrant.

SAS version 6.07 will support only standard and enhanced mode. Both modes mode will require at least 6 Meg of memory and additional memory would increase performance. The system will run with less memory in enhanced mode, with a performance degradation.

Multitasking and the Security of applications

Perhaps the most important distinction between OS/2 and Windows is the method in which multitasking is accomplished. OS/2 is a powerful operating system that supports preemptive, time sliced multithreading

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and multitasking. For example, there are features in the operating system to support multitasking such as threads, semaphores, signals, priority, separate address space, and a tasked based file system. In addition, OS/2 provides a robust environment for an application like SAS. Applications code and data are protected from being overwritten by other applications. To a large and sophisticated application such as SAS, this is a very important feature of an operating system ..

Windows on the other hand, was designed to be compatible with the original Windows programming model of earlier releases, real mode Windows 2.x. Multitasking is not preemptive, but cooperative. Applications must be very well behaved and must yield execution of the application at designated points in order for the system to achieve the appearance of multitasking. In effect, applications can run as long as they have work to do, and relinquish the CPU only when out of work. This means that some large applications may very well monopolize the CPU at the detriment of other applications. In addition, although code segments are protected against overwriting from other applications, data and allocated memory is shared between applications allowing for erroneous applications to easily corrupt other applications. Applications are not protected from unintentionally writing to other application's data areas. For these simple reasons, OS/2 is a much better operating system for network servers, mission critical applications, and SAS power users.

The performance of multitasking is obviously better on OS/2 than on Windows. On OS/2, there can be up to n SAS sessions running concurrently, although only two or three are really practical. However, in SAS 6.07 under Windows, only a single SAS session will be able to execute on a given PC. Windows simply does not provide the robustness and performance to multitask multiple SAS sessions. If multiple concurrent SAS sessions on a single PC is important to your application, OS/2 is the better platform than Windows.

Interprocess Communication. DOE. and OLE

Under OS/2, SAS supports three types of interprocess communications: pipes, named pipes, and dynamic data exchange. Pipes are used to invoke a standard C program from SAS, directing input into the standard input handle of the program, and retrieving the output from the standard output handle of the C program. Under OS/2, pipes work interactively where SAS can actually control the execution of the C program. (In fact, the SAS Install application does exactly this.) Under Windows, pipes are much more limited, and only serve to relieve the user from having to create an intermediate file. This is a small difference and is a result of the multitasking limitations of Windows. Given this limitation, pipes are not supported by SAS for Windows.

Named pipes on OS/2 are used to communicate from SAS to SAS or SAS to another application. (Named pipes are a supported device that a fileref can be assigned.) In addition, named pipes can be used locally or across a network such as Lan Manager, Lan Server, or Novell, or any network supporting the named pipe interface. Named pipes are used extensively in data collection and factory floor applications under OS/2 but could also be used in any application that needs to share or distribute data or results across applications. Named pipes are not supported under Windows 3.0 and will not be provided in Windows until a later release.

Dynamic Data Exchange (DDE) is supported on both OS/2 and Windows. DDE allows SAS to exchange data with any application that support DDE such as Microsoft Excel, Lotus 1-2-3, CimpleData, and others. DDE allows SAS to gather or broadcast data or information for a one time transfer to another application, or it can be used to create a hot link for continuous dynamic updates of the data.

Starting with Windows Release 3.1, Object Linking and Embedding (OLE) is supported by the operating environment. OLE allows objects created from one application to be embedded into the display of another application. SAS supports OLE in the SAS/AF product (Application's Facility), which allows objects created from other Windows applications to be embedded in a SAS/AF application and a SCL program. For example, using SAS/AF and SCL (Screen Control Language) a chart representing data from Lotus or Excel could be displayed and embedded in an SAS/AF program screen. The spreadsheet Excel or Lotus in this case, would control the object by continuously updating the chart in the program screen as the spreadsheet data dynami­cally changed. OLE also provides for permanent DDE links. That is, once the link is established between SAS and another OLE supported application, the link is maintained even if both applications are concluded and even if the PC is powered off. OLE allows for the connection to be dynamically re-established when one of the applications is invoked again. OLE provides a foundation for truely interrelated and cooperative applications in this decade on the PC. OLE is an integral part of Microsoft's "Information at your fingertips"

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vision and is currently only available on Windows. As it becomes available on OS/2, SAS will support it on that platform as well.

User Interface

Starting at OS/2 version 1.2,OS/2 and Windows 3.0 look nearly identical with respect to the user interface and the array of user controls available. For this reason, corporations can consider Windaws as an interim step to OS/2 because much .of the rettaining necessary for a new enviranment is due ta the user interface. Generally speaking, by loaking at a snapshot of a SAS screen, the differences between OS/2 and Windaws appearance is so slight that the underlying .operating enviranment cannot be distinguished. Both environ­ments have adopted IBM's Camman User Access (CUA)specificatian for designing the user interface. Therefore, SAS users maving from Windows ta OS/2 .or vice versa will have no problems adapting.

Windaws 3.1; due in late 1991 from Micrasaft, will provide enhancements for hand writing recognitian using speciai'tablets. Named "Pen Windows", this release pravides yet another interface toal, the tablet and pen. This interface has tremendous possibilities for laptap computing and for desktop camputing. Perhaps in the future, the tablet will be as prevalent as the mouse is today. For OS/2, the pen enhancements have nat yet been annaunced, although technically there is no reason OS/2 cauld nat suppart h~i1dwriting recognitian in the near future. The SAS System will initially use Pen Windows through the pen interface window. Initially, SAS will make no special use .of Pen Windaws. (Pen Windaws use wHl be cancentrated on laptops that do not meet SAS's memory .or disk requirements.)

An issue that many software vendors are investigating now, including SAS Institute, is which programming interface will be mare powerful and enhanced in the 1990's. There are twa competing APls, Presentatian Manager and Windows Graphics Device Interface (GDI). At stake is productivity .of saftware vendors and corporations which write in-hause software. Everyone wants an API that is provided an both platforms without performance degradatian .on either platfarm. IBM is firmly committed ta the OS/2 Presentatian Manager API, while Micrasaft is cammitted ta the Windaws GOI API. OS/2 PM is much cleaner and better designed than the Windaws GDI interface.

OS/22.0 (discussed later in this paper) presents a new user interface named the warkplace enviranment The warkplace metaphor attempts to provide the user with an ()bject .oriented system as compared to the traditianal PC action oriented system. Far.example, users will work more with files and documents that are assaciated with programs,' instead of the current method of working with a pragram and then selecting the data. Actian bars .or pmenus are replaced with pap up menus in the OS/2 shell, and drag and drap operatians will be as common as mause clicking is today. The Institute is currently warking on enhancementsta the SAS product to allow it to natively fit the new OS/2 warkplace model far the 6.08 release far OS/2.

I/O: FAT vs. IFS, HPFS

As stated earlier, multitasking is the mast important distinction between OS/2 and Windows, and the mast important distinctian that affects SAS. The secand mast important difference between the enviranments is the file system.

One .of the advanced features of OS/2 1.2 waslhe creating of Installable File Systems (IFS). IFS allaw for additional file systems to be installed to provide far increased performance to the operating system. Inthis

'way, the file system was separated from the .operating system, so that new and better file systems cauld be implemented without requiring a new operating system. The first of these IFS was the High Performance File System. HPFS features a file system that is optimized for multitasking and for I/O throughput. Tests with SAS indicate at least a 25% ta 50% increase in performance .of accessing SAS data sets and catalogs. Ta achieve this performance, HPFS uses lazy writes ta write data to the disk at oppartune times. Windows which is based on DOS uses the DOS tHe system called the File A1locatian Table (FAT). The FAT is an .old style file system mainly designed far flappy disks and is not an efficient system for advanced hard disks. Therefare, I/O under Windaws is generally slaw as is cansistent with DOS file Ijn This distinctian will generally demanstrate a performance penalty for SASrunning I/O intensive applications under Windaws, whereas the application running on OS/2 will generally run much faster. . .

Further advances in HPFS and other IFS are pramised and probable given the architecture of OS/2. Hawever,

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since Windows is based on DOS, an improved file I/O system will require a new DOS. Although a new I/O system for DOS is rumored, it is still years away from production.

As far as SAS data set limits are concerned, the limits are identical for both OS/2 and Windows. The size of a data set and the number of variables within a data set are only constrained by your disk partition size and the limitation of a 64 k segment inherent of the processor. A data set Is not limited by the number of observations, and the number of variables per observation is a maximum of 30,700 for variables of 2 bytes. The formula to calculate the maximum number of variables per observation is:

# variables = 61,400 / length of variable

The format of SAS data sets and catalogs is exactly the same under both environments. Data sets and catalogs may be copied across SAS Systems using DOS or OS/2 utilities. Proc CPORT /CIMPORT are not necessary to transport the version 6.07 files between OS/2 and Windows systems. In addition, version 6.06 data sets are compatible with version 6.07 data sets and engines will be available to read and write version SAS 6.04 data sets.

Data collection

Recently, the SAS System has become widely used in data collection activities on the factory floor. Consider­able development effort was allocated to ensuring SAS had the power for sophisticated data collection in version 6.06. Through the serial port on PCs, the SAS system can be interfaced to any piece of equipment supporting the RS-232 interface. To facilitate this, the DATA step supports an array of functions to facilitate the programmatic interface to any data collection equipment or robot. Measurement equipment, data collec­tion terminals, and even robots can be interfaced, and programmed from within SAS. Such features as named pipes, DOE, and functions such as WAKEUP, SLEEP, and OAT AMYTE functions are provided to facilitate data collection.

80th Windows and OS/2 generally support the COM ports in the same way so the features for interfacing to these devices is portable between OS/2 and Windows. 80th platforms serve as an acceptable data collection machine. However, there are two important distinctions that indicate that OS/2 is the better platform for data collection activities. First, as discussed previously, OS/2 provides for robust multitasking for mission critical activities, whereas Windows provides a much less robust environment (See discussion above on Memory management and Multitasking.) Additionally, many data collection applications use named pipe Interfaces within the SAS program. Named pipes are only supported under OS/2.

Number Crunching. Statistical applications

Although no benchmarks are available at this time, due to the SAS 6.07 product for Windows is still under development, all technical indications lead us to believe that numerical intensive applications wHi run more quickly under OS /2 than Windows on the same machine configuration. The reasons for this include 1) under OS /2 the scheduler will balance the allocation of the processor to tasks which need it most, whereas Windows has no real scheduler, and multitasking is accomplished by yielding the processor, 2) the process of coopera­tively yielding the processor wHi cause an inefficiency in numerical calculation performance, and 3) under Windows further overhead is required by the application to save and restore the state of the floating point processor at task switch points; this activity is provided by the OS/2 dispatcher. Numerical accuracy and precision will be exactly the same under both operating systems.

SAS products on OS/2 and Windows

As stated earlier, the SAS System under OS/2 and Windows will contain the same products for the 6.07 release. This is due to the SAS MultiVendor Architecture that allows the products to be ported to multiple architectures and operating systems concurrently. Additional features such as DOE, OLE, and named pipes are provided in order to allow the SAS System to optimize on the features provided by the operating system. In addition, in a few product areas, there are differences between the SAS releases, as detailed below.

SAS/ACCESS

SAS/ACCESS will provide engines to read and write data in the following formats. The engines below are supported on both OS/2 and Windows:

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• Lotus ® WKS files

• Dbase ® 11/ and IV files

The OS/2 release provides an engine for the OS/2 database manager for Extended Edition and the OS/400 database that runs on the AS/400. The Institute is investigating support for Microsoft's SOL server.

SAS/CONNECT

SAS/CONNECT software provides cooperative processing between the PC workstation and will provide support for micro-to-host communications. SAS/CONNECT allows for remote execution of SAS programs on a host, as well as facilitating file transfer of SAS data sets, catalogs, and external files. The following access methods are supported under OS/2:

• 3270 EHLLAPI interface utilizing Communications Manager

• APPC (LU 6.2) interface utilizing Communications Manager

• Serial communications (RS-232) and a DECNET task-to-task interface are being investigated

For the Windows release, the EHLLAPI interface is being targeted. Currently, communication product ven­dors that SAS has committed to support include Digital Communications Associates (DCA) and Attachmate.

SAS/SHARE

SAS/SHARE is being developed to provide a SAS file server for allowing multiple access to a data set or catalog by multiple users. Currently, SAS/SHARE will utilize OS/2 as the server platform. This SAS server is planned to be released as an experimental release in 6.07. The underlying communication interface will use NETBIOS.

SAS /SHARE will not be supported under Windows. The lack of true multitasking,. the lack of threads, and the lack of protection for applications are the reasons for not developing a SAS server under Windows. However, SAS running on Windows may be a client to a SAS/SHARE server running on OS/2.

Hardware

The following minimum requirements is recommended for the SAS 6.07 release on both platforms.

·80386

• 6 Meg Memory

• Math co-processor (80387)

• 110 Meg Hard Disk

• EGA, VGA, 8514/A, or XGA

• Mouse

Network Support

Network support is a requirement before moving to anew operating system. Network vendors have provided an entire array of networks and servers in the PC DOS market. Windows builds on this support by providing many requesters from popular networks in the Windows Setup installation program. Additionally, Windows allows much of the operating environment to be install~ on the network, loading only necessary pieces to the local hard disk. Under OS/2, network support has been slow to be provided from vendors other than IBM, Microsoft, and Novell. Other network vendors have taken a slow and cautious approach to supporting OS/2. Until OS/2 1.3 Standard Edition, executing applications from the network resulted in wasteful and slow loads of executable files. In OS/2 1.3, a change was made to the OS/2 kernel to attempt to load executable files from the network in the same approximate time as local loads. This feature is important for SAS as many corporations execute SAS from the network.

The SAS System uses no network specific APls, and thus interfaces to the various networks through the OS/2

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and Windows API. For SAS/SHARE, the NETBIOS API will be used to interface to networks.

OS/2 and Windows: A market perspective

Much in the press has centered around OS/2 and the introduction of Micros~ft Windo';"s a.o. For complete­ness, some general facts are presented concerning the sales trends. OS/2 1.1 was released in November 1988. Version 1.2 was released in September 1989 and version 1.3 was released in November 1990. The best release of OS/2 is version 1.3 as it achieves a reduction Inphysical memo.ry and hard disk requirements. The resolution of memory management bugs including problems with discarding and swapping, as well as Improved network loads of executable Images make this the best OS/2 yet. In addition, the system supports Adobe TrueType fonts, and the screen redisplay is quicker. Given this and the extensive effort at marketing OS/2, OS/2 has not provided a significant market for software vendors as expected. Windows on the other hand was Introduced in May 1990, after a year of the worst kept beta secret. The rollout of Windows was phenomenal. To date, over 2 million coples of Windows has sold, and over 50 hardware Vendors have signed up to bundle Windows with their PCs. In addition, over 45,000 software development kits have been shipped to independent software developers and corporations. There Is less development activity under"wayfor OS /2 regardless of OS/2's superior design. Most applications now targeted for OS/2 are network, file server, engineering, and statistical applications.

However, now that Windows 3.0 Is one year old, tt'!e user commlJnity is starting to recogni;ze the Inadequacies of Windows 3.0. Such problems as instability with multitasking, unrecoverable application errors, poor memo­ry management software, and the relative large PC configl,Jration required to. run newer Window's applications are' being recognized. On the other hand, the robustness, and reliability of 0$/2;s superior design Is begin­ning to be apparent, and each month more and more OS/2 applications are shipping. Users are finding that Windows really requires the same hardware configuration that OS/2 requires, and that OS/2 and OS/2 applications run better than their Window's counterparts on the same hardware configuration. Also, IBM continues to rollout improvements in performance and reductions in memory requirements for OS/2.

The future of OS/2 and Windows: OS/2 2.0. OS/2 3.0. Windows 32 bit

The early to mid 90s promise to bring a barrage of development and releases in both the OS/2 and Window's world. In 1991 as reported in the press, Microsoft plans to ship a DOS 5.0. DOS 5.0 Is planned to replace all previous versions of DOS, and become the underlying operating system for superior Windows perfor. mance. DOS 5.0 provides support for laptop power monitoring facilities, upper memory blocks, the ability to load in high memory device drivers, and an impr.oved Window's like sheil. In late 1991, Windows 3.1 is promised to be released which will support Pen Window's handwriting recognition. In addition, support for OLE and multimedia will be provided.

Wrth respect to OS/2 2.0, IBM Is planning to ship OS/2 2.0, the 32 bit OS/2 to users sometime in late 1991. Microsoft and IBM have announced that IBM is the primary developer. of this. operating system. The IBM OS/2 2.0 product appears to be.the best OS/2 yet!. OS/2 2.0, If true to it's marketing appeal, will provide "a better DOS than DOS", "a better Windows than Windows", and "a better OS/2 than OS/2". In fact, IBM is already demonstrating MS-DOS 5.0 and Digital Research's DR. DOS 5.0 under OS/2 2.0. IBM's promise for OS/2 2.0 Is that PC DOS, Windows 3.0, and OS/2 1.3 will run faster under OS/2 2~Othan the operating systems rUn natively. If this can be accomplished, all PC users would mOve to OS/2 2.0 iftor no otheneason than to run their old DOS applications, Windows applications, or OS/2 1.3 applications more efficiently. All of this Is possible, but only if the price Is right. As announced by IBM In both the US and Europe, OS/2 2.0 is a free upgrade from OS/2 1.3, and OS/2 1.3 price has been dropped to $150. The pricing for OS/2 2.0 has not been released but is believed to be below $200.

IBM is able to deliver this performance gain because under the cross licensing agreements with Microsoft, IBM has access to PC DOS, Windows, and OS/2 1.3 source code for optimization modifications.

In this new OS/2 2.0 environment, it will no longer be necessary to distinguish between ihe type of application you are running, because the OS/2 loader will invoke the application in the appropriate environment for you. In fact, even DOE will work between OS/2 and Window's applications.

The Institute Is already preparing for extensive testing for the SAS 6.07 product for OS/2 1.3 and Microsoft

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Windows under OS/2 2.0, anticipating that the OS/2 2.0 platform for OS/2 1.3 and Windows applications will be very popular. In addition, development is underway to provide a 32 bit version of the SAS System under OS/2 2.0 for the SAS version 6.08. The Institute is absolutely committed to OS/2.

Microsoft, on the other hand, is planning to upgrade Windows 3.0 to a 32 bit API. This 32 bit API will be provided in what Microsoft calls OS/2 3.0. This version of OS/2 under the direction of Microsoft with minimal approval from IBM, is developing the first portable version of OS/2 to be ported to RISC processors. The first processor to be targeted is the MIPS R4000 processor. As of the date of this paper. SAS Institute is continUing to investigate the 32 bit Windows platform.

One specific point should be made. Microsoft and IBM have two agendas for the near future. IBM states that OS/2 is the future operating system for PCs .. Microsoft, on the other hand, has stated that although the future of PC computing may inevitably be OS/2 in the future, for the next few years at least, Windows will be the operating system of choice for most PC users. Windows, shipping over 1000 applications now, has the applications to create a demand for the operating environment OS/2 appears to still be the superior operating system without the large demand everyone expected. However, with the emminent release of OS /2 2.0, IBM Is about to dramatically change the PC workstation operating system market.

Conclusions

This paper has provided a comparison of the differences between OS/2 and Windows and how the differenc­es relate to the SAS System version 6.07. SAS Institute does not recommend one of the environments over the other. The choice of operating environment really comes down to the use of the application. OS/2 provides for a more robust, multitasking environment. Windows provides for nearty the same user interface but in a more fragile environment. However, as software giant Microsoft concentrates on enhancing Windows in the future, we can expect future improvements, innovation and new products to appear.

SAS InstitUte will support both operating systems in the future. The SAS products will be identical on both platforms. Any feature of OS/2 or Windows that provides SAS with more power and flexibility will be support­ed on that operating system.

Clearty, each operating system has it's advantages. However, technically, there are less limitations and less disadvantages for using OS/2, while there are many advantages. The only disadvantages for using OS/2 include limited network support from many network vendors, lack of applications, and lack of development tools. The advantages are clearty that OS/2 is by far a superior operating system to Windows. It is robust, and provides true multitasking, extensible memory management, and protection of application address spaces. This makes OS/2 the preferred environment for mission critical SAS applications and applications that are so large that extensive virtual memory is required. OS/2 is also the choice for power users performing extensive numerical computations and running server applications such as SAS/SHARE.

However, the SAS release for Windows is functionally equivalent to the OS/2 release and the performance for most applications will be very similar. Windows provides SAS with a less stable environment, and the FAT disk I/O is substantially slower. Larger problems may suffer from the limited support of virtual paged memory, and will most likely run slightly slower.

The OS/2 2.0 release promised by IBM in late 1991, has the potential to propel OS/2 to the status once expected. By providing "a better DOS than DOS, a better Windows than Windows, and a better OS/2 than OS/2", IBM will be delivering to each PC user exactly what each user wants and needs. The SAS System for 32 bit OS/2 2.0 promises to be an ideal platform for SAS users.

Notes and Trademarks

The release dates for products to be delivered from IBM, Microsoft. and other corporations mentioned in this paper are dates as reported in the (public) press. These dates may not reflect official announced dates from these corporations. The dates were used in this paper merely to reflect upcoming releases of operating

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environment software and what plans SAS Institute has to support these new releases.

Cimple Data Standard Edition is a registered trademark of INOTEK Technologies Corporation.

dBASE IV is a registered trademarks of Ashton-Tate, Inc.

IBM, OS/2, PC DOS, Lan Server, and Presentation Manager are registered trademarks of International Business Machines Corporation.

Lotus is a registered trademark of Lotus Development Corporation

Microsoft Windows, Lan Manager, Excel, and SOL Server are registered trademarks of Microsoft Corporation.

Novell and Netware are registered trademarks of Novell, Inc.

SAS/AF, SAS/ACCESS,SAS/ASSIST, SAS/BASE, SAS/CONNECT, SAS/EIS, SAS/ETS, SAS/FSP, SAS/ IML, SAS/GRAPH, SAS/OR, SAS/STAT, SAS/OC and MultiVendor Architecture are registered trademarks of SAS Institute Inc.

Mark Cates Is the Manager of the PC Host Department at SAS Institute. He has held this position since 1985. This department is responsible for designing and developing the host layer of the Institute's MultiVendor Architecture for the PC DOS, OS/2, and Microsoft Windows. Mark holds a BS in Computer Science from North Carolina State University, a MS in Computer Science from the University of South Carolina, and an MBA from the Fuqua School of Business, Duke University. Mark may be contacted at the Institute by phone or fax, or on Internet at sasmwc@dev.sas.com

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