About This Guide

This publication describes Fortran input/output (I/O) techniques for use on Cray Research and on Silicon Graphics systems. It also contains information about advanced I/O topics such as asynchronous queued I/O and logical record I/O. Information about the interaction of the I/O library and the Cray Research Fortran 90 compiler, CF90, is also discussed. The information in this manual is pertinent for UNICOS systems, UNICOS/mk systems, and IRIX systems.

This document also serves as an I/O optimization guide for Fortran programmers on UNICOS systems. It describes the types of I/O that are available, including insight into the efficiencies and inefficiencies of each, the ways to speed up various forms of I/O, and the tools used to extract statistics from the execution of a Fortran program.

Information which is marked as available on IRIX systems is available with the MIPSpro 7 Fortran 90 compiler and the MIPSpro Fortran 77 compiler when using the -craylibs option.

Related Publications

The following Cray Research documents contain additional information that may be helpful:

  • Application Programmer's Library Reference Manual

  • Optimizing Code on Cray PVP Systems

  • Guide to Parallel Vector Applications

  • UNICOS Performance Utilities Reference Manual

  • UNICOS System Calls Reference Manual

  • UNICOS System Libraries Reference Manual

  • MIPSpro 7 Fortran 90 Commands and Directives Reference Manual

  • CF90 Ready Reference

  • CF90 Commands and Directives Reference Manual

  • Fortran Language Reference Manual, Volume 1

  • Fortran Language Reference Manual, Volume 2

  • Fortran Language Reference Manual, Volume 3

Obtaining Publications

The User Publications Catalog describes the availability and content of all Cray Research hardware and software documents that are available to customers. Customers who subscribe to the Cray Inform (CRInform) program can access this information on the CRInform system.

To order a document, call +1 651 683 5907. Silicon Graphics employees may send electronic mail to [email protected] (UNIX system users).

Customers who subscribe to the CRInform program can order software release packages electronically by using the Order Cray Software option.

Customers outside of the United States and Canada should contact their local service organization for ordering and documentation information.


The following conventions are used throughout this documentation:


This fixed-space font denotes literal items, such as pathnames, man page names, commands, and programming language structures.


Italic typeface denotes variable entries and words or concepts being defined.

[ ]

Brackets enclose optional portions of a command line.

In addition to these formatting conventions, several naming conventions are used throughout the documentation. “Cray PVP systems” denotes all configurations of Cray parallel vector processing (PVP) systems that run the UNICOS operating system. “Cray MPP systems” denotes all configurations of the CRAY T3E series that run the UNICOS/mk operating system. “IRIX systems” denotes Silicon Graphics platforms that run the IRIX operating system.

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