fdformat(1) on Solnix vs Linux and the BSDs
On Solnix, fdformat is the illumos /usr/bin/fdformat, which its own page says is superseded by rmformat(1). Its flags differ from FreeBSD fdformat(8) and NetBSD fdformat(1): -f means 'force' (not a density or a device), and -v is verify-after-format (not verify-only).
The manual pages
- Solnix: fdformat(1) from
pkgs.solnix.illumos-world-man· illumos.org - FreeBSD: fdformat(8) 15.1-RELEASE
- NetBSD: fdformat(1) 11.0
What Solnix runs
A default Solnix system runs the illumos fdformat at /usr/bin/fdformat, and no other variants are shipped. The page says rmformat(1) replaces it and provides most but not all of its functionality. The bundle has no Linux counterpart page.
Differences
| Compared with | Topic | What differs |
|---|---|---|
| FreeBSD | -f meaning | Solnix -f forces formatting without asking for confirmation. FreeBSD -f fmt selects a density by kilobyte format, as described in fdcontrol(8). The same flag letter does unrelated things.Source: Solnix fdformat(1) -f; FreeBSD fdformat(8) -f fmt |
| NetBSD | -f meaning and device selection | Solnix -f forces formatting. NetBSD -f device names the device to format, defaulting to /dev/rfd0a. On Solnix the device is an optional positional devname, e.g. floppy0 or rdiskette0.Source: Solnix fdformat(1) -f, OPERANDS devname; NetBSD fdformat(1) -f device |
| FreeBSD | device argument | FreeBSD requires a device operand, either a full path such as /dev/fd0 or an abbreviated name such as fd0. Solnix devname is optional and defaults to the first diskette drive, if one exists. Source: FreeBSD fdformat(8) SYNOPSIS, DESCRIPTION; Solnix fdformat(1) OPERANDS |
| FreeBSD | -v meaning | Solnix -v verifies each block after formatting. FreeBSD -v does not format at all and only verifies. A FreeBSD script that uses -v to check a disk would format it on Solnix.Source: Solnix fdformat(1) -v; FreeBSD fdformat(8) -v |
| FreeBSD, NetBSD | verification default | FreeBSD and NetBSD verify after formatting unless -n is given. On Solnix, verification happens only when -v is given, and the page documents no -n.Source: FreeBSD fdformat(8) -n; NetBSD fdformat(1) -n, DESCRIPTION; Solnix fdformat(1) -v, DESCRIPTION |
| FreeBSD | confirmation prompt and -q | Solnix -q only suppresses status messages. -f is what skips the confirmation. FreeBSD -q suppresses output and also skips confirmation. FreeBSD -y skips confirmation but still reports status.Source: Solnix fdformat(1) -q, -f; FreeBSD fdformat(8) -q, -y |
| FreeBSD, NetBSD | file system creation | Solnix writes a SunOS label by default. With -t dos (or -d) it also puts an MS-DOS file system on the media. FreeBSD and NetBSD only low-level format. Use newfs_msdos(8) (and newfs(8) on FreeBSD) afterwards.Source: Solnix fdformat(1) DESCRIPTION, -t dos; FreeBSD fdformat(8) DESCRIPTION; NetBSD fdformat(1) DESCRIPTION |
| NetBSD | -t meaning | Solnix -t takes dos or nec and selects the file system to install. NetBSD -t type names a diskette entry in /etc/floppytab whose parameters are used for formatting.Source: Solnix fdformat(1) -t dos, -t nec; NetBSD fdformat(1) -t type |
| NetBSD | -B meaning | Solnix -B filename installs a boot loader on an MS-DOS diskette and only works with -d or -t dos. NetBSD -B nbps sets the number of bytes per sector.Source: Solnix fdformat(1) -B; NetBSD fdformat(1) -B nbps |
| FreeBSD, NetBSD | density selection | Solnix selects density with fixed flags: -D, -E, -H, and -M with -t nec. FreeBSD uses -f fmt or -s fmtstr. NetBSD sets explicit geometry with -B, -S, -T, -C, -P, -G, -X and -I, or a named -t type.Source: Solnix fdformat(1) -D, -E, -H, -M; FreeBSD fdformat(8) -f, -s; NetBSD fdformat(1) OPTIONS |
| FreeBSD | exit status | FreeBSD documents exit 0 for success, 1 for formatting errors and 2 for invalid arguments. The Solnix text in the bundle has no EXIT STATUS section, so the manual shown does not say. Source: FreeBSD fdformat(8) EXIT STATUS; Solnix fdformat(1) (no EXIT STATUS in bundle) |
| FreeBSD, NetBSD | media and manual section | Solnix fdformat also formats PCMCIA memory cards and can unmount file systems first with -U. The FreeBSD and NetBSD pages mention only floppy disks. FreeBSD documents it in section 8, Solnix and NetBSD in section 1.Source: Solnix fdformat(1) NAME, -U; FreeBSD fdformat(8) NAME; NetBSD fdformat(1) NAME |
Standards
- POSIX: fdformat is not a POSIX.1-2024 utility.
Writing portable scripts
- Do not script fdformat across systems:
-f,-v,-qand-tmean different things on Solnix, FreeBSD and NetBSD. Branch on the OS and use that system's own flags. - Create the file system as a separate step on FreeBSD and NetBSD (newfs_msdos(8), newfs(8)). On Solnix,
-tdos does it as part of the format.
Every difference here is taken from the manual pages linked above: Solnix's published page, Linux (man-pages and the GNU and util-linux manuals), FreeBSD, OpenBSD and NetBSD. Each row names its source. Where a manual is silent, this page is too. Compiled 2026-10-26. Found a mistake? Mail hackers@lists.solnix.io.