1. NAME AND TITLE

FBSAM: User-Storage--Magnetic Disk Data Manipulator.

2. CONTRIBUTOR

Oak Ridge National Laboratory, Oak Ridge, Tennessee.

3. CODING LANGUAGE AND COMPUTER

Fortran IV and Assembler Language; IBM 360/370.

4. NATURE OF PROBLEM SOLVED

FBSAM provides rapid movement of large blocks of data directly between user storage arrays and magnetic disk data sets. No buffer space is required. Large reductions in data transmission time and number of I/O requests can be obtained. Moves can be concurrent with each other and with computation.

FBSAM is intended for use by Fortran programmers with little or no Assembler Language experience.

5. METHOD OF SOLUTION

FBSAM contains a number of entries which check for errors and invoke various Assembler Language packages. The status data for a given data set are compacted into a single array. A form of random access is available. A powerful note-point method of random write and retrieval is available. The use of three concurrent functions eliminates the real time associated with data transmission tasks by allowing them to proceed concurrently with other tasks.

6. RESTRICTIONS OR LIMITATIONS

Data to be moved must be stored in contiguous locations and no Fortran FORMAT facility is allowed. The data sets produced are not compatible with normal Fortran I/O. Best efficiency is obtained using long logical records. The speed is slightly better than that using track overflow with Fortran sequential operations. Because chaining is used, secondary allocations of disk space are not permissible.

7. TYPICAL RUNNING TIME

The CPU time is negligible. Large logical records are transferred at the full disk rotation speed without a rotational delay between blocks.

8. COMPUTER HARDWARE REQUIREMENTS

FBSAM is operable on the IBM 360/370 computers.

9. COMPUTER SOFTWARE REQUIREMENTS

Fortran IV and Assembler Language compilers are required.

10. REFERENCE

W. A. Rhoades, "The FBSAM Data Transmission Package for IBM 360/370 Computers," ORNL-TM-5199 (January 1976).

11. CONTENTS OF CODE PACKAGE

Included are the referenced document and one (1.2MB) DOS diskette which contains the source code input.

12. DATE OF ABSTRACT

March 1984.