NESC9684 MULTITASKER.
MULTITASKER, Multitasking Kernel for C and FORTRAN Under UNIX
NAME OR DESIGNATION OF PROGRAM, COMPUTER, DESCRIPTION OF PROGRAM OR FUNCTION, METHOD OF SOLUTION, RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM, TYPICAL RUNNING TIME, UNUSUAL FEATURES OF THE PROGRAM, RELATED AND AUXILIARY PROGRAMS, STATUS, REFERENCES, MACHINE REQUIREMENTS, LANGUAGE, OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED, OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS, NAME AND ESTABLISHMENT OF AUTHORS, MATERIAL, CATEGORIES
[ top ]
[ top ]
To submit a request, click below on the link of the version you wish to order.
Only liaison officers are authorised to submit online requests. Rules for requesters are
available here.
| Program name | Package id | Status | Status date |
|---|---|---|---|
| MULTITASKER | NESC9684/01 | Arrived | 01-APR-1988 |
Machines used:
| Package ID | Orig. computer | Test computer |
|---|---|---|
| NESC9684/01 | DEC VAX 11/780 |
[ top ]
3. DESCRIPTION OF PROGRAM OR FUNCTION
MULTITASKER implements a multitasking kernel for the C and FORTRAN programming languages that runs under UNIX. The kernel provides a multitasking environment which serves two purposes. The first is to provide an efficient portable environment for the development, debugging, and execution of production multiprocessor programs. The second is to provide a means of evaluating the performance of a multitasking program on model multiprocessor hardware. The performance evaluation features require no changes in the application program source and are implemented as a set of compile- and run-time options in the kernel.
MULTITASKER implements a multitasking kernel for the C and FORTRAN programming languages that runs under UNIX. The kernel provides a multitasking environment which serves two purposes. The first is to provide an efficient portable environment for the development, debugging, and execution of production multiprocessor programs. The second is to provide a means of evaluating the performance of a multitasking program on model multiprocessor hardware. The performance evaluation features require no changes in the application program source and are implemented as a set of compile- and run-time options in the kernel.
[ top ]
4. METHOD OF SOLUTION
The FORTRAN interface to the kernel is identical in function to the CRI multitasking package provided for the Cray XMP. This provides a migration path to high speed (but small N) multiprocessors once the application has been coded and debugged. With use of the UNIX m4 macro preprocessor, source compatibility can be achieved between the UNIX code development system and the target Cray multiprocessor. The kernel also provides a means of evaluating a program's performance on model multiprocessors. Execution traces may be obtained which allow the user to determine kernel overhead, memory conflicts between various tasks, and the average concurrency being exploited. The kernel may also be made to switch tasks every cpu instruction with a random execution ordering. This allows the user to look for unprotected critical regions in the program. These features, implemented as a set of compile- and run-time options, cause extra execution overhead which is not present in the standard production version of the kernel.
The FORTRAN interface to the kernel is identical in function to the CRI multitasking package provided for the Cray XMP. This provides a migration path to high speed (but small N) multiprocessors once the application has been coded and debugged. With use of the UNIX m4 macro preprocessor, source compatibility can be achieved between the UNIX code development system and the target Cray multiprocessor. The kernel also provides a means of evaluating a program's performance on model multiprocessors. Execution traces may be obtained which allow the user to determine kernel overhead, memory conflicts between various tasks, and the average concurrency being exploited. The kernel may also be made to switch tasks every cpu instruction with a random execution ordering. This allows the user to look for unprotected critical regions in the program. These features, implemented as a set of compile- and run-time options, cause extra execution overhead which is not present in the standard production version of the kernel.
[ top ]
[ top ]
[ top ]
[ top ]
[ top ]
NESC9684/01, included references:
- Eugene D. Brooks III:A Multitasking Kernel for the C and Fortran Program Langage
UCID-20167 (September 1984)
[ top ]
[ top ]
[ top ]
14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS
The multitasking kernel is written almost entirely in C with machine dependencies isolated in just a few routines. Thus, the kernel can be readily moved to new multiprocessors once a C compiler has been developed for the target machine. The kernel is compatible with the UNIX symbolic debugger, dbx. The compatibility of the kernel with a symbolic debugger is a very powerful feature which is lacking in most multitasking implementation.
The multitasking kernel is written almost entirely in C with machine dependencies isolated in just a few routines. Thus, the kernel can be readily moved to new multiprocessors once a C compiler has been developed for the target machine. The kernel is compatible with the UNIX symbolic debugger, dbx. The compatibility of the kernel with a symbolic debugger is a very powerful feature which is lacking in most multitasking implementation.
[ top ]
[ top ]
NESC9684/01
| File name | File description | Records |
|---|---|---|
| NESC9684_01.001 | Information file | 33 |
| NESC9684_01.002 | MULTITASKER source,... in UNIX TAR format | 224 |
Keywords: FORTRAN.