It's basically unlimited for files only! There IS a maximum number of subdirectories you can have per any single directory. For Linux kernels this is capped at 31999 subdirectories. For comparison with some commercial Unixes: HP-UX is 32767 and AIX is also 32767. I actually hit this limit in a commercial application I helped develop, so I'm well aware of it. When you go over with the mkdir(1) command you'll get an error like: mkdir: cannot create directory `/tmp/x/31999': Too many links or with the mkdir(2) system call you'll get errno = EMLINK. The reason for this is that each subdirectory contains a ".." entry, which increases the inode link count on its parent directory. This is artifically capped at 32000 inside the Linux source code (even though the field is a full 32-bit unsigned integer). This is controled by these kernel include file lines: include/linux/ext2_fs.h:#define EXT2_LINK_MAX 32000 include/linux/ext3_fs.h:#define EXT3_LINK_MAX 32000 include/linux/ufs_fs.h:#define UFS_LINK_MAX 32000 Supposedly you could recompile the kernel yourself with these increased if you wanted to go beyond 32000. Do note though that for portability with other systems (Unixes, NFS, tar command, etc.) you will want to stick to a 16-bit integer because most other software besides the Linux kernel only allocates a 16-bit field for the inode link count. Deron Meranda
