GNU Info

(fdutils.info)Variable format devices

---

Next: Fixed format devices Prev: Device numbers Up: Device numbers

---

Enter node , (file) or (file)node

Variable format devices
=======================

   Variable format devices don't have an intrinsic geometry.  When using
these devices, the geometry has to be set either by using autodetection
(Note: Autodetection), or by using the `FDSETPRM' or `FDGETPRM'
ioctl.  The latter ioctl can be issued using the `setfdprm' (Note:
setfdprm) and `getfdrpm' (Note: getfdprm) programs. With the
default settings, common formats are detected transparently, and you
can access any disk transparently using the variable format devices.

   The geometry information is kept as long as the disk is in the drive,
and is discarded as soon as the disk is removed, unless the geometry has
been declared _permanent_ by using setfdprm's `-p' flag (Note:
setfdprm).