AIX® 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, 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 /usr/bin/cpio command (although the/usr/sysv/bin/cpio command does not have this restriction), and the object file archive format, restricting the ar command. You can archive large files with backup.
The 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 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.