# part(8)

## NAME

         part - partition table editor

## SYNOPSIS

         part [device] ...

## DESCRIPTION

         Part is a screen oriented partition table editor.

         While editing you will see six lines of numbers, the first line shows the
         device  name  and  its geometry (number of cylinders, heads and sectors),
         the second shows the start and end of the  drive  or  partition  you  are
         working  on,  the  last  four  lines  show  the  different  partitions or
         subpartitions.  All numbers except  those  on  the  second  line  can  be
         edited.   Question  marks  are showed instead of numbers if the partition
         table is not loaded yet.  You have to select a device and type 'r'.

         Editing is a simple matter of moving  around  with  the  arrow  keys  and
         changing  the  values  with  + and - (or PgUp and PgDn), or by typing the
         desired value.  The '?' key will give a small list of commands,  the  '!'
         key gives advice on how to make a new entry.

         The spacebar toggles between showing the size of the  partition  and  the
         last sector on the partition.  Useful to check if a partition is adjacent
         to the next.

         The 'm' key is "magical", it lets you cycle through a set of  interesting
         values for the base or size of a partition.  These values are: Aligned to
         a cylinder, taped to other partitions (inside or outside), or filling out
         holes.  Use this key!

         Minix subpartition tables or extended  partitions  may  be  edited  after
         hitting  the  '>'  key.  The number of this partition will be shown after
         the device name on the second row, e.g.  /dev/hd0:2.  Minix  subpartition
         tables  are  shown  as is, but extended partition bases are translated to
         absolute offsets on  the  screen  to  hide  the  gory  details  of  their
         implementation  from  the innocent user.  (Hit 'p' if you dare.)  The '<'
         key will bring you back to the enclosing partition table.

         With arguments, part will  use  the  given  devices  or  files.   Without
         arguments,  part will use all interesting block devices in /dev sorted by
         device number and starting with /dev/hd0.

         Values that are out of range, overlapping, or otherwise strange are shown
         in  reverse  video.   Values that may possibly be a problem for operating
         systems other then Minix are shown in bold characters.

         The name of the device is highlighted when it has not been read yet.

         Head or sector numbers are highlighted if the partition does not start or
         end at a cylinder boundary.

         The base and/or size field  is  highlighted  if  they  fall  outside  the
         device,  if  they are inside some other partition, if the base equals the
         device's base (no room for the boot sector), or if the size is zero.

         Part complies with the good old UNIX tradition of trusting the user.   It
         will write any table, no matter how bad.  You have been warned.

         By the way, as far as Minix is concerned there is absolutely no reason to
         make  partitions  start precisely on a cylinder or track nor does it have
         to be an exact number of cylinders long.  Minix only looks  at  the  base
         and  size  of  a  partition, the geometry of the drive doesn't have to be
         correct.  Other Operating systems can be very picky about partitions that
         are  not  aligned.   Some  partition  editors may refuse to edit a table,
         others may even make a mess of the table.   The  only  exception  is  the
         first  partition,  it  traditionally  starts  on the first track, not the
         first cylinder.  All editors must understand this.  (Subpartition  tables
         are Minix specific, so there is no reason at all for any alignment.)

      Extended Partitions
         Extended partitions are a mess that is only made slightly better by  part
         by translating the base offsets to absolute numbers.  It is better to use
         DOS fdisk to create them, but if you insist on using part  then  this  is
         what they should look like:

              The extended partition entry in the  primary  partition  table  must
              cover the whole logical partition space within it.

              The area thus created is split in segments, each segment contains  a
              partition table in sector 0 and one (just one) logical partition.

              The first entry  of  a  segment's  partition  table  describes  this
              logical partition: it's partition ID, base and size.

              The second entry is an extended partition that  describes  base  and
              size  of  the  next segment (partition table and logical partition).
              The last segment's partition table is empty, or contains one logical
              partition.

## SEE ALSO

         fd(4), hd(4).

## BUGS

         You can have a table read, messed up, and written in no time, be careful.

         You can't type head or sector numbers directly.

         Sectors are counted from 0  for  consistency,  but  the  partition  table
         counts from 1 like DOS addresses them.  Most confusing.

         You can't write a backup copy to a file, that's what dd(1)  with  count=1
         is for.

## AUTHOR

         Kees J. Bot (kjb@cs.vu.nl)