Monster Media 1994 #2/Monster Media No. 2 (Monster Media)(1994).ISO/utils1/flpkit10.zip/FLOPTOOL.DOC

Text File | 1994-07-19 | 19KB | 346 lines

                       Floppy Tool Kit, Version 1.0
                              William Luitje
                              20 January 1994

         This  is  a collection of 5 small utilities  which  will
         help  you  use  your floppy disks  better.    Since  you
         probably  worry more about how to get better  speed  and
         storage  out  of your hard disk,  this is not  likely  a
         matter of pressing concern to you.   However,   floppies
         are going to be used for quite a while and by spending a
         few minutes with these utilities you can make things  go
         a little bit faster each time you use a floppy.

         FLOPPARM
         ~~~~~~~~
         Floppies  have  been  around a long time and  have  been
         improved since they first came out, not only in capacity
         but  also  in their mechanical  speed.    Unfortunately,
         system software can't tell what the best speed to  drive
         a  floppy is and must be compatible with old drives  and
         so uses conservatively slow parameters.   When accessing
         a  floppy,   the BIOS uses a table called the Disk  Base
         Table for these parameters.   This table can be found by
         looking  at interrupt vector 0X1E.  Since this table  is
         usually  set  up in RAM by DOS,  it is an easy thing  to
         modify  it for modern,  fast drives.   FLOPPARM will  do
         this for you conveniently; simply run it with one of the
         three arguments SLOW,  MEDIUM, or FAST.   The parameters
         which are affected are:

           ■ step rate and head unload time, which are parameters
             of the disk controller chip.

           ■ head settle time,  which is the amount of time taken
             after stepping from one track to another to wait for
             the head mechanism to stop vibrating.

           ■ motor  startup time,  which  is the amount  of  time
             taken to allow the spindle motor speed to  stabilize
             after it first starts up.

         SLOW  is  provided  for compatibility  with  really  old
         drives;  MEDIUM is somewhat faster than DOS 5;  and FAST
         is  pedal  to  metal!  When run,  FLOPPARM  displays the
         parameters used.  If run with no or an illegal argument,
         FLOPPARM  will  display  a usage hint  and  the  current
         values of the parameters.

         FLOPPARM also allows you to specify your own  parameters
         by using the CUSTOM argument followed by an equals  sign
         and  the four parameters (step rate,  head unload  time,
         head  settle time and motor startup time)  separated  by
         commas  (no  spaces allowed).   For  example  a  command
         equivalent to FLOPPARM MEDIUM would be

         flopparm custom=13,15,1,2

         Legal values for step rate and head unload time are from
         0   to  15.    Legal values for  head  settle  time  (in
         milliseconds)   and  motor startup time (in  1/8s  of  a
         second) are from 0 to 255

         Note that FLOPPARM is not a TSR and does not take up any
         DOS memory;  it simply modifies a table which is already
         created by DOS. Once you decide which parameters to use,
         just  put  a line invoking FLOPPARM in your AUTOEXEC.BAT
         file and enjoy a modest increase in floppy speed.

         FLOPTEST
         ~~~~~~~~
         How  can  you  tell if you have set  your  floppy  drive
         parameters too fast?  I've included a utility which will
         seek  to  every  track of the disk,  read a  sector  and
         report any errors it finds.   The seek pattern is called
         a "butterfly test"  since it reads the first track, then
         the last track, then the second track,  then the next to
         last  track,  etc.   This will really give the  drive  a
         workout!

         This  test requires a formatted floppy which has no  bad
         sectors  (FLOPTEST can't tell if an error is due to  the
         drive not working properly or due to a bad disk).  It is
         a read only test so it shouldn't change any data  on the
         disk.    There  are two parameters:   one is  the  drive
         letter  and the second is the number of passes  to  run.
         If  you  get any errors and your floppy is ok  then  you
         should  back  off  one  or  more  of  the  floppy  drive
         parameters and test again. Here is an example

            floptest a 20

         If  you  are fortunate enough to have more than  2  disk
         drives  (this applies both to FLOPTEST and to the  other
         utilities in this package),  you can refer to the  third
         drive as c and the fourth drive as d, even if you have a
         hard drive that goes by either of those names.   I  know
         this  is  confusing  but this test operates at the  BIOS
         level  and has no idea what  letter DOS has assigned  to
         your  third  and  fourth floppies.   I  had a choice  of
         confusing  people who had more than 2 floppy  drives  or
         confusing everybody by making you specify the drive with
         a number rather than a letter.  That's life.

         You  can  also use FLOPTEST to see if a floppy disk  has
         any  bad  sectors.   If you run it with only  the  drive
         letter  specified,  then it will attempt to  read  every
         sector  and  report any failures.  Since FLOPTEST  makes
         only  one attempt to read each sector,  it will warn you
         if a sector is getting weak.

         FLOPSKEW
         ~~~~~~~~
         The  most  important improvement you can make  in  using
         your  floppy  drives  is  to  format  your  disks  using
         FDFORMAT  by  Christoph  Hochstätter  or ATFMT  by  Oleg
         Kibirev.    These programs allow almost complete control
         over  how your disks are formatted.  Among other things,
         you can put up to 820K on 5¼"  DSDD disks,  1.48  meg on
         5¼"  HD disks and 1.7 meg on 3½" HD disks.   In terms of
         speeding up floppy disk transfers,  these programs allow
         you to control the way sectors are arranged on  a track.
         This concept is  called  sector  sliding by FDFORMAT and
         sector spinning by ATFMT; in the US it's known as sector
         skewing.   Basically,  the idea is  that since  there is
         some mechanical delay in changing heads or tracks it may
         be  desirable to put the first sector of a new  head  or
         track "later" in the track so the computer doesn't  have
         to  wait for the floppy to make  a  complete  revolution
         before  that sector can be read.   See  these  programs'
         documentation for more details on how  this works.   The
         time  savings  when reading or  writing  a floppy can be
         substantial  when you format it using the  optimal  skew
         parameters  and,   as an added benefit,   formatting  is
         faster, too.

         You  can  specify  head  skew and  track  skew  in  both
         FDFORMAT   and   ATFMT  by  the  X  and  Y   parameters,
         respectively.    The DOS FORMAT program does not support
         sector  skewing  at  all;  this is equivalent  to  using
         FDFORMAT  or ATFMT with X and Y both set to zero.    But
         what values should you use for these parameters?   Well,
         when FDFORMAT first introduced this feature,  I  wrote a
         batch  file  which  formatted a test disk  with  various
         combinations of the head and sector skew parameters  and
         then  measured how long it took to copy a large file  to
         the floppy.   It took about an hour to run and tested 16
         combinations of X and Y values for just one disk format.
         FLOPSKEW  does  the same job in just a few  seconds  but
         tests even more combinations of parameter values.

         To use FLOPSKEW,  first decide which setting of FLOPPARM
         to  use and then run FLOPPARM with that  parameter since
         the  step  rate  and head settle time will  both  affect
         skewing.   Then, format  a disk of the type and capacity
         for   which  you  want  to  find  the  optimal   skewing
         parameters  with  the  X and  Y  parameters both  0  and
         interleave  1.    Although FLOPSKEW is a non-destructive
         test,  you should use a freshly formatted disk to ensure
         that these  parameters are set correctly,  otherwise the
         test will give strange results.   If you don't specify X
         and Y,  FDFORMAT and ATFMT default to the correct values
         except  that they both must use an interleave of  2  for
         the 5¼" 1.44  meg and 3½" 1.7  meg formats (and for this
         reason  it doesn't make sense to use sector skewing with
         these formats). DOS FORMAT always formats with no sector
         skewing and interleave 1.

         Then,  simply run FLOPSKEW with the drive letter of  the
         floppy you want to test as the only parameter.   Here is
         an example  command and its results for a double density
         (720K) 3½" disk on my system:

            flopskew b

            Find Optimal Head & Track Skew, Ver 1.0
            9 Sectors/Track, 80 Tracks, 2 Sides

            Head Skew Times (milliseconds):
            X:       0   1   2   3   4   5   6   7   8
            Time:   32  54  74  95 116 137 158 178 199

            Track Skew Times (milliseconds):
            Y:       0   1   2   3   4   5   6   7   8
            Time:  232  53  74  95 116 137 158 178 199

            Interleave:  1
            Minimum skewing parameters:  X=0, Y=1
            Recommended skewing parameters:  X=1, Y=2

         First  you  are shown the format of the  test  diskette,
         then  some  test  results and  finally  the  recommended
         skewing  parameters.    If  you are interested  in  some
         technical  details about the test you  should  read  the
         next few paragraphs; otherwise you can skip ahead to the
         next  section.   Just use the recommended parameters  to
         format your disks and expect your diskette throughput to
         become about 30% faster.

         Two  tests are run to find the best values for the  Head
         Skew  parameter (X)  and the Track Skew  parameter  (Y).
         The  head skew test is run by reading the last sector of
         the  first  track using head 0 and  then  measuring  how
         long, in milliseconds, it takes to read the first sector
         of  that  same  track  with  head 1.   (If the  disk  is
         formatted with only one side this test is not run.)  The
         track skew test is run by reading the last sector of the
         first  track  using head 1  (if testing a  double  sided
         disk)  and then  measuring how long it takes to read the
         first  sector of the second track using head 0.   In the
         results above, the second line tells how long this took,
         in milliseconds,  for each of  the sectors on the second
         track read.

         Let's look at the example data to see what we can learn.
         First,  notice that the times to read different  sectors
         in the head skew test increase by about 22 milliseconds.
         This  is just the time it takes to read one  sector  for
         this format.  The formula is

         sector read time(ms) = 1000 * 60sec/min * rpm / sectors

         For  this format the drive rotates at 300  rpm and there
         are 9 sectors so the time to read a sector works out  to
         22.2   milliseconds.    This formula can be modified  to
         figure the time to read an entire track by dropping  the
         final division by sectors.  In this case, it is 200 ms.

         To  determine the  best values for X and Y,  the program
         finds  the smallest time and the corresponding number of
         sectors skipped from the line above.  The data show that
         for my system no sectors should be skipped when changing
         heads  so  the optimal head skew parameter,  X,   is  0.
         Typical values are 0 or 1 for most systems.  Now look at
         the  results  for the track skewing test;  the  time  to
         change tracks without skipping any sectors is 232!  This
         is  the  time  it takes to read a whole track  plus  the
         sector  plus some overhead.   In this case the 0  sector
         skew  provided by DOS format and the default values used
         by  FDFORMAT  and ATFMT yield a big waste of  time  when
         reading  or writing multiple tracks.   On my system  the
         optimal track skew parameter,  Y, is 1.   Typically,  it
         ranges from 1 to 3 on the systems I have looked at.

         Now  notice  that the program recommends values for  the
         skew  parameters  which are 1 greater than  the  optimal
         values.  This is because the penalty for choosing a skew
         value which is too small is severe:   you have to wait a
         whole revolution,   in this case 200  ms, when  changing
         tracks.     On  the other hand, the penalty for having a
         skew value which is one too big is only 22  ms.    Since
         some  software may introduce  an additional  delay  when
         changing  tracks,   it is a safe bet to be  conservative
         when  choosing the  skew values.  If you  regularly  use
         floppies  on two computers you should  run  FLOPSKEW  on
         both  of them and choose the higher of  the  recommended
         skew parameters.

         Take the values of X and Y found by the above  procedure
         and use them to format your floppies in the future.   To
         make this easy, you can create a batch file, 4DOS or CED
         alias,   or  FDFORMAT or ATFMT configuration  file  with
         those parameters in it.  Any time you format a floppy or
         read  or  write  a floppy formatted this way it will  go
         faster.

         How much faster?   Well,  assuming the most likely  case
         that  only  track seek is a problem and that the  sector
         skewing  is  only  off by 1 or 2,   then  on average the
         computer  has  to wait for a full disk revolution  every
         second  track it reads.   Eliminate the wait and you can
         reduce  the time spent reading and writing by 1/3.  When
         formatting  a diskette, skewing only affects  the verify
         operation so the time reduction is somewhat less,  about
         20%.

         FLOPRPM
         ~~~~~~~
         If you are having trouble reading or writing  diskettes,
         especially with a large number of sectors per track, the
         problem may lie with the speed at which the drive spins.
         FLOPRPM will test this condition for you.   Simply place
         a  formatted disk in the drive you want to test and  run
         FLOPRPM with the drive letter as the only argument.  The
         program  will  then test and display the  rotation  rate
         continuously  until you press a key.   Normally,  all PC
         floppy  drives  will  run within an RPM or  two  of  300
         except for 5¼"  HD drives which run at 360.   If you are
         having  problems  and the speed of your drive is off  by
         more than that,  you may be able to get better operation
         by adjusting the speed of your drive.  Unfortunately, no
         general guidelines  can be given about how  to  do  that
         because drives differ in their design.

         FLOPINFO
         ~~~~~~~~
         This  program simply reads the existing format of a disk
         and  displays  it.   With all of the  different  formats
         supported  by FDFORMAT and ATFMT it's nice to know  what
         format a particular disk is.   Also, since some of these
         formats require a TSR to read, you might want to know if
         a  particular floppy can be read on another system which
         doesn't have a copy of that TSR available.  Or,  perhaps
         you  want  to quickly find out whether a floppy is HD or
         DD.

         FLOPINFO takes one parameter, the drive letter.  Here is
         an example command  and response,  again  for a 720K 3½"
         disk

    flopinfo b

    Floppy Disk Information, Ver. 1.0 by [e-mail]
    OEM Name: IBM  3.3, 512 Bytes/Sector, 9 Sectors/Track, 80 Tracks, 2 Sides
    2 FATs, 1 Reserved Sectors, 112 Directory Entries
    Total Capacity is 730112

         Registration
         ~~~~~~~~~~~~
         While this software may be freely copied and used,  I do
         request  that you register it if you use it.   Just send
         me  either  a postcard or some e-mail telling me who you
         are and where you are and what you like or dislike about
         the  program.  This is only partially an ego massage for
         the author.   I  enjoy writing useful utilities and have
         several other pieces of freeware out floating around the
         net  so  I  would  like feedback about which of them  is
         worth expanding and supporting.

         This software is intended to be safe to use.   All tests
         and information programs are read only.   About the only
         problem  you  might have is that if you set  the  floppy
         drive  parameters  too fast you may get  read  or  write
         errors.    Never  the less,  in using this software  you
         assume all risk should anything go wrong.  I  think that
         is pretty unlikely, but, hey, sometimes it rains fish!

         William Luitje
         2677 Wayside Drive
         Ann Arbor, MI 48103
         USA

         Internet:  [e-mail] or
                    [e-mail]