ECP(1) ECP(1)
NAME
ecp - fast copy, handling errors
SYNOPSIS
ecp [ -bcprvZ ] [ -B block-size ] [ -e max-errors ] [ -i
issect ] [ -o ossect ] [ -s sector-size ] sectors input
output
DESCRIPTION
Ecp copies sectors disk sectors of the specified input file
to the specified output file. Ecp copies multiple sectors
(a `block') at a time for speed. When ecp encounters an I/O
error, it transfers the current block again, assuming the
file is seekable, one sector at a time, prints the sector
number(s) of the error(s), and continues copying.
Options are:
-b reblock input on short reads; this was used mainly when
reading a pipe on standard input on 4.2+BSD systems.
-B sets the block size (16,384 bytes by default) to block-
size.
-c ask for confirmation on /dev/cons before starting the
copy.
-e sets a maximum number of consecutive I/O errors to per-
mit at the beginning of the copy before quitting to
max-errors. Lots of consecutive errors may indicate a
deeper problem, such as missing media. By default there
is no limit.
-i seeks to sector issect (assuming zero-origin) before
beginning input.
-o seeks to sector ossect (assuming zero-origin) before
beginning output.
-p print reassuring progress reports; helpful mainly when
dealing with cranky hardware.
-r copy sector groups in reverse order, assuming the files
are seekable; this is most useful when input and output
overlap.
-s sets the sector size (512 bytes by default) to sector-
size.
-v verify the copy by rereading the input and output files
Page 1 Plan 9 (printed 11/18/24)
ECP(1) ECP(1)
after copying all sectors. This is intended to force
the disk to deliver the actual data written on it rather
than some cached copy. The locations of any differences
are printed.
-Z `Swizzle' the input: stir the bits around in some fash-
ion. Intended for diagnosing bad disks by copying a
disk to itself a few times with swizzling on (to defeat
caching in operating systems or disk controllers).
SEE ALSO
fcp in cp(1), dd(1), dup(3)
BUGS
-i, -o, -r, -v and error retries only work on devices capa-
ble of seeking.
The set of options reflects decades of experience dealing
with troublesome hardware.
If the input file is a tape and the last record on the tape
before a file mark is less than blocksize bytes long, then
ecp will read through past the file mark and into the next
file.
Page 2 Plan 9 (printed 11/18/24)