Version 8 represents a major step forward for SAS Institute and is the first release of a new generation of SASâ software. Customers confronted with a new generation of software are concerned about the cost of moving their applications to that new release and are reluctant to move everything at once.

This paper reviews some of the reasons why customers want to move some or all of their applications to Version 8. We recognize that many sites will not want to move everything forward at the same time; therefore, this paper discusses techniques to make partial migrations (mixing Version 6 and Version 8 applications) and techniques for running critical systems in parallel (to facilitate comparing Version 6 to 8). Maintaining data libraries in the proper format (Version 6 versus 8) and cross version compatibility issues in a client/server environment are two of the concerns addressed.

Version 8 contains a number of features that were beyond the scope of Version 6. These are features that required major re-writes of the SAS system. The new Version 8 features provide the major motivation for moving to Version 8. While this paper does not go into detail about these features, the following is a list of the author's favorite new features:

1. Output Delivery System (ODS): You have many more options for the output created by SAS procedures, allowing you to:

• Transform procedure output into a SAS data set
• Render output as colorful HTML pages with embedded hyperlinks
• Operate seamlessly with word processing software using RichText and/or Postscript files (experimental)

1. Long Variable Names: Allows for richer name space for tables(data sets) and columns (variables)
2. SAS Explorer: Provides a rich visual front end to the SAS System
3. Asynchronous SAS/CONNECTâ Program Submits: Allows you to do work in the foreground while remote submits are being processed in the background
4. Dynamic Libnames: Gives transparent access to external databases with SAS/ACCESSâ dynamic libname statements
5. CEDA: Allows access to SAS datasets created by multiple operating systems without having to go through a transport process or bring up a server on the machine that created the file
6. Advanced Database Features: Provides integrity constraints to ensure data conforms to user-defined rules and provides versioning to allow you to keep more than one copy of the same file

You would be motivated to convert to Version 8 if any of the previous features are important to you.

Motivation, however, is only part of the story. Version 8 represents a new generation of SAS software. Many sites are going to be conservative about installing new generations off software that is mission critical. One of the central messages of this paper is that your movement from V6 to V8 can be done at a your pace.

In the past, converting from one release of a software product to another was like moving into a new house. The customer made a decision to move, set up elaborate systems to prepare for the move, and expected to be out of commission for a while after the move completed.

The move to a new release was seen as a complete operation (all applications must migrate forward at the same time) that was irreversible. With this kind of model, it is no wonder that software users grimace every time a vendor introduces a new release.

SAS Institute understands how painful upgrades to software can be. One of the design goals of Version 8 was to facilitate a seamless transition from Version 6.

The Institute expects customers to evolve from Version 6 to 8 rather than do a massive conversion. We have worked hard so you will not have to go through the total and irreversible kind of conversion that you went through between Versions 5 and 6.

To achieve the goal of seamless transition, Versions 6 and 8 complement one another. Some of the Version 8 features that facilitate a complementary relationship are:

1. SAS automatically senses the format of a library, e.g. is it a Version 6 library or a Version 8 library? SAS programs that access Version 6 libraries will (for the most part) run unchanged in Version 8.
2. Read, Write, and Update access to Version 6 SAS data files are supported.
3. Read access to Version 6 SAS catalogs and SQL views are supported.
4. You can mix Version 6 and 8 clients and servers. For example, a Version 8 client can process data from a Version 6 SAS/SHARE server (and vice versa).
5. Library and catalog concatenation (a new Version 8 feature) allows you to move some data forward into a V8 format while leaving other data in Version 6 format.

All of these features taken together mean that most Version 6 applications can run unchanged in Version 8 and that it is possible to migrate part of an application to Version 8 while leaving other parts in Version 6. The conversion from Version 6 to Version 8 can be painless and does not have to be complete.

In later sections, two of the above features (concatenation and mixed release client/server) will be discussed in detail.

Library concatenation allows you to reference two or more SAS libraries with a single libref. A complete description of library concatenation may be found on the CD ROM SAS Language Reference: Dictionary, First Edition.

Library concatenation allows you to combine libraries that are processed by different engines. For example, suppose there are some files in a Version 6 library and some other files in a Version 8 library. Further, suppose that the application needs to process the collection of files in both libraries. The following syntax can be used to establish a single libref ("MYLIB") that combines the Version 6 and Version 8 libraries:

Catalog concatenation allows the combination of two or more catalogs into a single logical catalog. A complete description of catalog concatenation may be found on the CD ROM SAS Language Reference: Dictionary, First Edition.

In the above example a Version 6 and a Version 8 library were concatenated into a single library named MYLIB. All of the catalogs in the concatenation with the same catalog name will be logically combined.

Library and catalog concatenation provides a method of combining Version 6 and 8 libraries. You can then decide which parts of the library to upgrade and which parts should remain in a Version 6 format.

You would want to upgrade a data file, a data view, a catalog file, or a catalog entry for any one of the following reasons:

1. To exploit new Version 8 features. For example, you may want to have update access through an SQL view.
2. The Version 6 format is incompatible with your intended usage in Version 8 (see Appendix 1 of this paper for details). For example, suppose your application expects to be able to update FRAME entries in a catalog. Version 8 will only allow updates to catalog entries that are in Version 8 format.
3. To change or extend your application such that some parts of the application run only in Version 8.

You would not want to upgrade your data if either of the following were true.

1. You expect Version 6 and 8 clients to need access to the data and you do not want or you cannot have multiple copies of the data.
2. You are comparing Versions 6 and 8 and you need the data stored in a form that both releases can get to.

Effectively using library concatenation assumes that you start with a Version 6 library. You then decide which pieces of this library you need to convert to a Version 8 format (see reasons 1-3 above). You copy any SAS files to the Version 8 library with PROC COPY and you copy selected catalog entries with PROC CATALOG.

To illustrate how this might work for you, consider an example of a Version 6 library, which contains:

In the above example the user could initially run their application in Version 8 without changing a thing.

There are going to be some sites that want to run their applications in Version 6 and Version 8. A cautious customer, for example, would experiment with Version 8 by running their applications in both releases. Another customer may be comfortable with moving some groups of users to the new release. For example, you may want to have your applications developers running Version 8, but your end users run Version 6. Finally, there will be customers in the business of delivering data in the form of SAS data files. These customers will want to deliver a Version 6 or a Version 8 form of the same file. The data producer, however, wants their Version 8 file not to be restricted to Version 6 features. For example, the data producer would want their Version 8 deliverables to have long descriptive variable names.

The SAS System offers some features to assist those customers who need to run Version 6 and Version 8 at the same time.

For example,

The option may be set with the options statement:

or in the SAS configuration file. For example, on a UNIX system,

There will be some customers who want to run Version 8 and fully exploit Version 8 features, but who have the need to create Version 6 data files to deliver to their clients. To do this, however, requires stripping out all of the Version 8 specific feature set from the file. For example, all variable names greater than eight characters would have to be renamed to fit the Version 6 eight-character limit. A SAS customer who is in the business of delivering SAS data sets will want to be able to easily deliver a Version 6 or Version 8 form of the file. Manually stripping out Version 8 specific features is tedious.

PROC COPY, when used with VALIDVARNAME=V6 (see above), will do this for you.

For example,

data employee;
LastName = 'Smith';
FirstName = 'John';
EmployeeID = 50;
run;

libname v6lib V6 'path';
options validvarname=v6;

proc copy in=work out=v6lib;
select employee;
run;

The resulting Version 6 data file, V6LIB.EMPLOYEE will contain the variables LASTNAME, FIRSTNAM, and EMPLOYEE and will be usable by any Version 6 or Version 8 application or SAS program.

Up to now this paper has been covering traditional SAS applications represented by one user and one process on one machine. The SAS System, however, has client/server extensions represented in products like SAS/SHAREâ and SAS/CONNECTâ .

When moving a client/server application forward, you have the choice of:

1. Moving some or all of the clients forward
2. Moving just the server forward or
3. Moving both client(s) and server forward

You may ask which of these three approaches makes the most sense. The answer to that question is going to be "it depends". The point is that the Version 8 system gives you the ability to mix and match Version 6 and Version 8 client/server scenarios. For example, one customer may wish to move their SAS/SHAREâ clients to Version 8 so that the clients can take advantage of some of the new Version 8 client side report writing features (such as ODS). That same customer may see no advantage to moving their server forward.

A SAS/CONNECTâ or SAS/SHAREâ customer may be using a server on another machine. At your site it may be that one machine environment has Version 8 available before another. A customer may wish to move their client or server forward to Version 8 when Version 8 is available on their machine. You do not have to wait until Version 8 is available on all of the machines that make up your client/server application.

There are some restrictions to mixing Version 6 and Version 8 client and servers. See Appendix 2 for a set of summary tables detailing what you can and cannot do in a mixed setting.

Version 8 was built with features that enable a slow migration or a complete and total migration. Many applications will require no changes at all to run under Version 8, while others may require some minor adjustments (such as using PROC COPY to move your data from a Version 6 format to a Version 8 format).

The new features in Version 8 provide the primary motivation for moving forward. The move can be total or partial, but either way it should be relatively painless.

For the most part, Version 6 applications can run unchanged in Version 8. There are some features, however, which require a customer to do something to their source or their data in order to run in Version 8. If you do not use any of these features, your transition from 6 to 8 should be seamless. If you do use some of these features, then this section tells what you need to do to convert from Version 6 to Version 8.

The tables in this appendix use the following conventions:

R = Read Access

W= Write Access

U = Update Access

Depending on the SAS Data Library member that is being accessed, compatibility between Version 6 and Version 8 varies. For example, under SAS/SHAREâ and SAS/CONNECTâ Remote Library Services (RLS), SAS Data Files are compatible as follows:

For SAS Data Views, compatibility varies, this time depending on the type of Data View - Data Step, SAS/ACCESSâ and PROC SQL and the setting of the RMTVIEW option. Again, considering SAS/SHAREâ and SAS/CONNECTâ RLS, for Data Step and PROC SQL SAS Data Views,