Fortran Unit Numbers¶

Products: Abaqus/Standard Abaqus/Explicit

References¶

About Execution Procedures

Overview¶

Abaqus uses the Fortran unit numbers outlined in the following tables. Unless stated otherwise, you should not attempt to write to these Fortran units from user subroutines.

For Abaqus/Standard, you should specify unit numbers 15-18 or unit numbers greater than 100. For Abaqus/Explicit, specify units 16-18 or unit numbers greater than 100 and ending in 5 through 9, such as 105, 268, etc. You cannot write to the .sta file.

Fortran Unit Numbers¶

Abaqus/Standard Unit Numbers¶

Unit Number	Description
1	Internal database
2	Solver file
6	Print output (.dat) file (you can write to this file)
7	Message (.msg) file (you can write to this file)
8	Results (.fil) file
10	Internal database
12	Restart (.res) file
19-30	Internal database (temporary files). Units 21 and 22 always write to disk
73	Text file containing mesh beam section properties (.bsp)

Abaqus/Explicit Unit Numbers¶

Unit Number	Description
6	Print output (.log) file
12	Restart (.res) file
13	Old restart (.res) file (if applicable)
15	Analysis preprocessor (.dat or .pre) file
23	Communication (.023) file
60	Global package (.pac) file
61	Global state (.abq) file
62	Temporary file
63	Global selected results (.sel) file
64	Message (.msg) file
65	Output database (.odb) file
67	Old package (.pac) file (if imported from Abaqus/Explicit)
68	Old state (.abq) file (if imported from Abaqus/Explicit)
69	Internal database; temporary file

Domain Parallel Unit Numbers¶

If using domain parallel:

Unit Number	Description
70	Local package (.pac.1) file for CPU #1
71	Local state (.abq.1) file for CPU #1
73	Local selected results (.sel.1) file for CPU #1
80	Local package (.pac.2) file for CPU #2
81	Local state (.abq.2) file for CPU #2
83	Local selected results (.sel.2) file for CPU #2

Each additional CPU adds three files with unit numbers incrementing by 10.

Source: Abaqus 2025 FD02 Execution Guide