The newfs command makes a Berkeley 4.2 UNIX file system (UFS) on the
specified device file. The A/UX version of HD SC Setup invokes newfs
when creating a UFS.
Each file on the system is represented by an inode, which contains critical
information about the file, including ownership, permissions, size, and so
on The newfs command allocates disk space for inodes when the UFS is
created.
By default, newfs creates an inode for each 4 kilobytes (kb) of available
space (2 kb on A/UX 3.0.1 and previous versions). Since each inode takes
up 128 bytes on disk, the space dedicated for inodes (or the inode
overhead) amounts approximately 3% of the total filesystem space (6% on
A/UX 3.0.1 and previous versions). On a 1 gigabyte drive, this works out
to be 32 megabytes (MB) or 250,000 inodes (64 MB or 500,000 inodes on A/UX
3.0.1 and previous versions).
If the average size of the files you use is much greater than 4 kb, for
example, large, bit-mapped, color graphics, you may want to reclaim some of
the inode overhead. Use the -i option to newfs to specify a larger value
of bytes-per-inode (or the inode density). Figure 1 graphically depicts the
inode overhead on differently-sized filesystems given inode densities of 2,
4 and 8 kb.
For example, if all the files you use contain at least 16 kb of data, you
would choose the bytes-per-inode to be 16384. You need to manually execute
the newfs command from the A/UX CommandShell. Important: This must be
done when the filesystem is created. If you already have data on this disk
drive, be sure to back-up your data before re-creating the filesystem.
Assuming the filesystem was previously formatted with HD SC Setup on an
external SCSI drive (id 5) on the external main board SCSI bus (bus 2),
you would enter the following command.
newfs -i 16384 /dev/dsk/c205d0s3 other
The filesystem device name is identified as /dev/dsk/cx 0yd0sz where x
specifies the bus (1-4), y is the SCSI ID number (0-6), and z is the
slice number.
Note: If the data on the filesystem will be predominantly Macintosh files
in the AppleDouble format, for example, plain text files, be sure to
allocate additional inodes. The AppleDouble format requires two inodes per
file, one for the resource fork and one for the data fork.
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