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(fdutils.info)floppymeter

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floppymeter
===========

     `floppymeter' [`-f'] [`-w' WARMUP-DELAY] [`-W' WINDOW]
     [`-c' CYCLES] [`-h'] DRIVE

   The `floppymeter' program measures characteristic parameters of a
floppy drive and floppy controller, such as the rotation speed of the
drive, the data transfer rate of the controller, and the resulting raw
capacity of a disk track.  To use this program, insert a disposable
floppy in the drive, and type `floppymeter --'DENSITY, where density
describes the density of the disk used for the test. (Should be one of
`dd, hd' or `ed'). *CAUTION: the data on the disk will be erased*.
This program should be used to verify whether the drive and controller
are out of tolerance if you experience problems with some high capacity
formats.  It only needs to be run once per drive: although a disk is
needed to perform the measurements, the measured data only depend on
the drive and the controller, and not on the disk.

   To measure the raw capacity of the disk track, the floppymeter
program formats the first track of the drive in a special way that
allows it to read the raw data (gaps and headers) of the disk. *Thus,
all data previously stored on that disk is lost*.

   The rotation speed is measured by timing the return time of a
`readid' command.  In order to gain more precision, the command is
issued many times in a row. During this phase, the number of rotations
til the start of the test, the average time per rotation til the start,
and a sliding average of the times of the last 30 rotations is printed,
and updated continously.

   The data transfer rate is deduced from the two parameters above.

   At the end of the program, all parameters (raw capacity, duration of
one rotation, and data transfer rate) are printed again, as well as
their relative deviation to the standard value.  Finally, it suggests a
capacity deviation description line, which can be directly pasted into
the drive definition file (Note: Drive descriptions).

   Usually, the data transfer rate should not deviate more than 150 ppm
from the expected value, and the rotation speed of the drive should not
deviate more than 3000 ppm from the expected value.  If these deviations
are bigger, you may get problems with certain high capacity formats.

   If the raw capacity of the drive is too small, some high capacity
formats may become unformattable on this drive/controller combo.

   If on the other hand, the raw capacity of the drive is too big, you
may get problems when writing to a disk formatted by this drive on
another drive with a smaller raw capacity. In order to avoid this,
increase superformats gap parameter (`-G').

`-h'
     Prints a short help

`--dd'
     Tells the program that we use a Double Density disk.

`--hd'
     Tells the program that we use a High Density disk.

`--ed'
     Tells the program that we use an Extra Density disk.

`-f'
     Runs the measurement non interactively.  With this option, the
     program doesn't ask for confirmation, and doesn't display the
     continously updated values during the rotation speed measurement.

`-W WINDOW'
     This value describes how many rotations are used for the
     computation of the sliding average. Default is 30.

`-c CYCLES'
     Describes the number of rotations clocked during the rotations
     speed determination test. Default is 1000.

Bugs
----

   This program is quite new, and may have bugs. Here are a few
suggested tests to check its sanity:
   * The deviation of the data transfer rate solely depends on the
     controller. It should not be different between two drives
     connected to the same controller. However, the drive rotation
     speed may be different for different drives.

   * All data transfer rates (for double, high and extra density) are
     derived from a same master frequency. Thus the _deviation_ of the
     data transfer rate should be independant of the density used.