ddppaacc -- Command

De-fragment a COHERENT file system
ddppaacc [-qq] _r_a_w__d_e_v_i_c_e

Command  ddppaacc   de-fragments  the  COHERENT  file   system  on  _r_a_w__d_e_v_i_c_e.
Defragmentation leaves each  file in the file system physically contiguous.
This reduces  the number  of seeks  needed to access  a file,  and threfore
permits disk I/O  to run at its maximum speed.   The default algorithm also
sorts the  i-nodes by  modification date  and puts the  oldest ones  at the
beginning  of  the  partition.   This  helps  the file  system  remain  un-
fragmented longer.

You must  uummoouunntt the target file  system _r_a_w__d_e_v_i_c_e before you  run ddppaacc on
it.   Failure to  do so  will corrupt  the file  system.  For  example, the
command

    dpac /dev/rat0a

tells ddppaacc to map the first partition on the first drive and prompt whether
to continue.  _r_a_w__d_e_v_i_c_e  must be a partition or a  floppy disk rather than
an entire hard drive.

ddppaacc begins by making a map of the file system.  It displays a histogram of
its activity as  it builds the map; this lets  you see what the kernel must
do in order to access each file.  When it has finished the file system map,
ddppaacc prompts you and  asks whether to quit, continue with defragmentatation
using the default  date sort, or to continue but  to use an unsorted method
of defragmentation.  ddppaacc does not use terminfo or termcap for its display,
and is  intended for  use on the  console's aannssiippcc terminal  setting.  This
lets you run it from a bootable floppy disk.

_S_e_e _A_l_s_o
ccoommmmaannddss, ffmmaapp, ffsscckk, qqppaacc, ssppaacc, uuppaacc

_N_o_t_e_s
To see how fragmented a file system is, use the command ffmmaapp.

Note that you  can also de-fragment a file system  by copying it to a tape,
then  deleting  it and  restoring  it  from the  tape.   Another method  of
defragmentation is  to use the command  ccppddiirr to copy the  file system to a
spare partition (should you have one  that is large enough), then using the
spare partition in place of the old partition.

Please note that if you  use ddppaacc incorrectly or without sufficient amounts
of RAM  or spare disk  space, you can  damage or destroy  your file system.
_N_e_v_e_r run  ddppaacc on the partition-table device (e.g.,  /dev/at0x), or on the
root device.  _C_a_v_e_a_t _u_t_i_l_i_t_o_r!

ddppaacc was written by Randy Wright (rw@rwsys.wimsey.bc.ca).
