WHAT IS MODEL 204?

Sandy Stanhope

Database Administrator

Most of you have used administrative systems at YSU and recognize the name “Model 204.” As a student, you probably use Model 204 for SOLAR and SID; as a faculty or staff, you may use systems such as PATRON, PERMREC and REG. But what is Model 204? Model 204 is a database management system with supporting products from Computer Corporation of America (CCA). Customized administrative systems have been developed in Model 204 at YSU since 1985 and include most of the Student Information Systems (SIS) and other systems such as Payroll and Space Reservations.

Model 204 Database Management System

Model 204 is a flexible, high-performance database with relational capabilities. It is a mature, reliable mainframe product whose performance, functionality and connectivity have been continually enhanced for over 30 years. Being an established product does not mean that it is “old”. With the 4 releases during the last 11 years, Model 204 has increased throughput almost 300% while CPU consumption was reduced by 34% and physical I/O was reduced by 39%.

The Model 204 database engine is the software layer that physically creates and maintains data files and fields and processes requests for data. It is flexible, and possibly unique, in that minor structural changes such as adding new files and fields can be made while the database application subsystems are active. Since database files are self-contained, even major modifications cause only particular files to be unavailable.

Model 204 has many integrity features. It insures the integrity of data resources in our multi-user environment with hundreds of concurrent users by applying sophisticated locking mechanisms. When you experience the record locking “feature” in an application, remember that record locks assure that one update in progress is not corrupted by another. Due to Model 204’s complex backup and recovery routines, no data has ever been lost due to failure of software or hardware systems. The quality of the Model 204 software is evidenced by the virtually non-existent downtime due to system software failures.

Seven levels of security are available within Model 204 as well as interfaces to system-wide, third-party security software. When you log on to Model 204, YSU’s RACF security is invoked through the interface to authenticate your userid and password. Model 204 security verifies your access to subsystems such as PATRON or PERMREC.

Where Model 204 particularly excels, however, is in the high-speed data access it achieves through performance features such as its advanced indexing. CCA has pioneered bit-mapped indexing with complex Boolean retrievals and has continued to improve this technology for over 25 years. Model 204 also supports hashing, B-tree and record list indexing in addition to bit mapping and can combine these indexing techniques to optimize data access. A Model 204 site was the winner in the peak online activity for transaction processing category in the 1998 Winter Very Large Database (VLDB) Survey Program. Model 204 achieved 1800 TPS (transactions per second) and IBM’s DB2 followed with 300 TPS.

Why is this high performance important for YSU? Currently, the hundreds of concurrent users of the over 30 administrative Model 204 subsystems in the online environment share access to over 90 database application files. These files occupy approximately six gigabytes of data storage. The student course file alone contains over 4,400,000 records. A database engine that can resolve query and update requests efficiently is essential to maintain the sub-second response typical in our interactive Model 204 environment.

Why will a high performance database engine become increasingly important in the future? Data demands at YSU continue to grow. Most University departments can relate to the need to keep more data and retain data longer. Also, data types that include audio, video, and images pose even greater potential data demands. Disk storage systems are now available that can store not only gigabytes (billion), but also terabytes (trillion) and even petabytes (quadrillion) of data. Internet-based applications with their unlimited availability would increase access demands on the database systems. Handling such data volumes with more data and users requires a powerful, scalable database engine. Model 204 can manage almost limitless amounts of data and maintain performance.

Performance Options

Two “add-on” products are available to further enhance Model 204’s power. Multiprocessor/204, MP/204, is in use at YSU and increases throughput by balancing workload among processors on multi-processor mainframes. Parallel Query Option, PQO, distributes a single query across multiple copies of Model 204.

Development Tools

Model 204 programs are written in User Language, a proprietary fourth-generation language that integrates data access and processing logic. User Language is flexible, English-like and fully integrated with the Model 204 database. It allows rapid interactive application development. Also, the same program can be run in the online interactive and nightly batch environments.

Other tools are used for application development productivity. Tools from CCA include a screen painter for developing online user interfaces, a procedure editor for maintaining User Language programs, and a data dictionary for documenting and reporting about data in the database. A third-party product provides interactive debugging.

Connectivity

Most organizations today have a variety of hardware platforms, operating systems, and database management systems that need to work together. Graphical user interfaces (GUI) such as Web browsers are also important to them. Although CCA remains focused on its primary mission of providing a high performance mainframe database, Model 204 can communicate with other host applications and CCA offers “add-on” interfaces with varied configurations such as web and client/server. Model 204’s thread manager acts as a gateway into the database and handles all the diverse interfaces. “Add-on” connectivity products available from CCA include:

· Horizon integrates User Language with industry standard communications protocols such as TCP/IP, allowing for communication across various platforms.

· Connect* provides connectivity between Model 204 and Windows or UNIX systems using either Standard Query Language (SQL) or Remote Command Line (RCL).

· MQSeries interfaces to IBM’s message queueing middleware.

· WebGate provides Web enablement with a three-tier architecture using a Windows NT Web server.

In addition to CCA’s offerings, connectivity options are available from other vendors.

Summary

What is Model 204? Model 204 is a robust, reliable and continually evolving mainframe database. Its flexibility, rich functionality and interactive development environment have allowed an integrated application infrastructure to be developed with minimal staff. Its inherent power continues to provide impressive performance as the volume of applications, data and users increase.

What could Model 204 become? Connecting with other environments could leverage the power of Model 204 and the investment in the applications. A Web interface, for example, would allow a more intuitive and available user access to the Model 204 data. The capabilities of Model 204 could thereby be extended to further benefit the University.