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.ig
	@(#)wdutest.8
	@(#)Copyright (C) 1985 by The Institute of Algebraic Meditation
..
.TH WDUTEST 8
.SH NAME
wdutest \- winchester driver formatting and testing program
.SH SYNOPSIS
.B /etc/wdutest [-r]
.SH DESCRIPTION
.I Wdutest
is an interactive program for testing and formatting a hard
disk attached to the SASI controller on Comet32 machines.
It can only be run under a floppy diskette unix (see
.IR vmflop (8))
since the disk controller cannot be used for anything else
at the same time.
If you have already opened (accessed) the disk, execute
.I wduioctl close
first to make sure the disk is closed (interrupts off).
.LP
Formatting and write testing destroys data
on the disk.
.I Wdutest
warns about such operations before proceeding,
unless warnings are explicitly turned off.
This should be done only when the disk contains
no useful data.
.LP
.I Wdutest
is used as the first step in generating a genix
system on a new machine (see
.IR sysgen (8)),
and perhaps later on to reformat a disk that has developed
several bad spots.
It can (and probably should) be used periodically to go over
the entire disk with the test command in verify (or read) mode
in order to discover problems.
Use the
.B -r
flag in this case to make the disk read-only.
.LP
.I Wdutest
includes extensive interactive help, so the commands will not
be described in great detail here.
The command structure is similar to that of
.IR mkpt (8).
For most keywords a unique abbreviation is sufficient.
.SH FORMATTING
To begin with, the genix disk unit is selected and
formatting parameters appropriate for the hardware in question
are loaded from a file.
For example, a file Rodime40 (40 megabyte Rodime disk) might
contain the lines
.nf

blocksize         512    ; sector size assumed by genix
heads               8    ; number of heads
cylinders         640    ; number of cylinders
landingzone       639    ; where the disk is stopped
interleave          8    ; interleave factor

.fi
Such files for all known disk types should be included in the
system distribution.
The commands needed to format the disk are then as follows:
.nf

> disk 1                 ; select disk 1 (system disk)
> load Rodime40          ; load the parameters
> show format            ; make sure you got it
> set warning 0          ; don't warn about disk writes
> format                 ; format the disk

.fi
When
.I wdutest
exits it writes a file
.I /etc/wdutab
containing the formatting parameters and known defects.
This file is loadable as such in case you are re-formatting
an old disk.
Formatting parameters can also be set manually but this
should not be necessary.
.SH TESTING
The command to start a test cycle is simply
.nf

> test                   ; start testing

.fi
The default parameters for testing include:
.nf

operations               write, verify (2 passes)
size of one operation    128 sectors (max)
test area                entire disk
passes over test area    4

.fi
The write patterns are taken from a set of 16 fixed patterns.
The disk is tested sequentially from lowest to highest sector.
Defects found are appended to the list of new defects, and
at the end this list is merged into the list of known defects
(unless merging is turned off).
.LP
Current test parameters can be seen with
.nf

> show test              ; display test parameters

.fi
An interesting parameter to alter is "segments", which divides
the test area into segments that are tested alternately.
Disk arm "torture testing" (for those who enjoy such things)
is achieved by setting operation to "seek" and segments to 2.
A very high value for segments causes overlapping tests.
If you're really paranoid, you can set the operation type
to "write, read, and compare" (the program pretends that there's
such a command to the disk controller).
.LP
Test commands can be interrupted (control-C) and can be continued
or cancelled after the interrupt.  
The basic sequence of preparing a disk consists of formatting 
and testing until no more bad blocks are found.
.SH DISK COMMANDS
Most of the available disk controller commands can be performed
manually, for example
.nf

> dc                     ; enter command loop
dc> tur                  ; test unit ready
dc> inq                  ; show the 4 inquiry bytes
dc> t 12340              ; translate to physical address
dc> quit                 ; quit the loop

.fi
Errors during the manual commands are treated in the same way as
during the automatic testing.
.SH ERROR INFO
The file
.I /etc/wduerr
contains error descriptions used by
.I wdutest.
These are not coded in the program since it's not exactly clear
how each error should be treated.
An entry in this file has the following form:
.nf

class code type
short description

.fi
Class and code are hexadecimal numbers identifying the error.
The type keyword tells how to treat the error, and is one of
the following:
.nf

noerror          -  not an error (code 0 0)
ignore           -  not a real error (code 1 2 presently)
format           -  media error in formatting fields
defect           -  media error with valid block address
hardware         -  disk controller not ready or defective
command          -  error in command

.fi
Only those errors marked as defects are added to the defect list
(provided they have a valid block address).
The 2nd line in the error information is a human-readable
description printed out by the program.
.SH FILES
.nf
/etc/wdutab              log file
/etc/wduerr              error info used by wdutest
.fi
.SH SEE ALSO
sysgen(8)
.SH BUGS
Never tested under realistic conditions, i.e. with bad disks.
If you want to do us all a big favor, throw your disk out
the window a few times and then test it.
DataMuseum.dk

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