AIX 4.2 or later provides support for files greater than 2 gigabytes so that users can store large quantities of data in a single file. Many, but not all, AIX commands support the use of files larger than 2 gigabytes. Additionally, some commands have large file support with limitations.
In many cases, commands that do not support large files do not utilize files of any size to begin with, such as the date, echo, nice, kill commands and others.
This support also does not extend to specific system-controlled files, such as /etc/passwd, /etc/inittab, files in /etc/security, system accounting files, etc. Consequently, commands that only utilize these system files, such as commands to administer users and system security (mkuser, su), system accounting commands (acctcom, prdaily), and general system controlling commands (init, penable) do not have large file support.
Other commands do not support large files because they work with files of a specific format defined to have a maximum of less than or equal to 2 gigabytes. These include the XCOFF file format, defining the format of object files and executable files. The file headers that define XCOFF do not have fields defined to support files this large, and the system would not be able to load an executable file of this size. Commands that utilize these files, such as ld, as, m4, strip and so on, do not have large file support.
The header format of the pack, unpack, and pcat commands does not have enough characters to store a file size over 2 gigabytes.
Additional file formats also prevent files of their type from being larger than 2 gigabytes. These include some archiving utilities restricted in format by industry standards, such as the cpio, pax, and tar (you can archive large files with backup) commands, and the object file archive format, restricting the ar command.
The AIX print spooling subsystem has been enabled on the frontend to support the submission, manipulation, and cancelation of files larger than 2 gigabytes. However, the default AIX printer backend, the piobe command, does not support files of this size. This means print jobs larger than 2 gigabytes can either be sent to a remote printer or print server that can handle these large files, or an alternate user or vendor-supplied backend that comprehends large files could be used.
Note: A print job larger than 2 gigabytes would likely take several days to complete.
Finally, there are commands for which the user files used are not reasonably expected to ever be larger than 2 gigabytes. For example, although a directory may contain large files, the directory file itself may not exceed 2 gigabytes. Hence, commands such as mkdir and rmdir do not support large directories. Other examples in which support is unnecessary would be using the wall command to broadcast the contents of extremely large files to all terminals, or using the nroff command to process over 2 gigabytes of written text in a single file.
The following commands all support files larger than 2 gigabytes. Commands which do not appear on the list do not support large files. Commands with limited large file support are marked with an asterisk (*) and an explanation of their limitations follow the list.
|aclget||auditcat *||auditconv *||auditselect *|
|awk *||backup||bdiff||bsh *|
|lpd *||lpq *||lpr *||lprm *|
|lpstat *||ls||make *||move|
|pr||proto||qcan *||qchk *|
|qdaemon *||qpri *||qprt *||qstatus *|
|rdist *||rdump||rembak *||restore|
The printer commands support files larger than 2 gigabytes on the printer frontend only. The default AIX printer backend, the piobe command, does not support files of this size. This applies to the following commands:
The shells support I/O redirection of files that are larger than 2 GB. No other support for files larger than 2 gigabytes is offered in the shells. This applies to the commands bsh, csh, ksh, Rsh, and tsh.
Note: The sh command is a link to the ksh command.
The awk and nawk commands are able to handle data files larger than 2 gigabytes. However, awk and nawk scripts themselves may not be this large.
The find command will process files larger than 2 gigabytes, but it will not allow the use of the -size Number flag where Number is larger than 2 gigabytes.
The make command will operate with targets and dependencies that are larger than 2 gigabytes, but a makefile itself may not be this large.
The audit commands auditcat, auditconv, and auditselect support trail files that are larger than 2 gigabytes, but they do not support bin files larger than 2 gigabytes.
Attention: DO NOT attempt to send a large file to a pre-AIX 4.2 or non-AIX machine with the rdist command. Doing so will result in undefined behaviors and in rare cases, loss of data.