CD-BENCH v1.1


	 Many  people think that the data transfer rate of CD-ROM  drives
      is constant from the beginning to the end of the disc, but this  is
      not  always true: at times it varies only a little, other times  it
      varies  very much.  In the latter case, common benchmarks report	a
      completely wrong result because they suppose that the reading speed
      is constant, so they read only at the beginning of the disc.

	 Has  your drive a constant data trasfer rate?	My program  gives
      you an accurate answer.  CD-BENCH reads the disc in four	different
      points  and displays four results, so you can see if and	how  much
      the speed varies.

	 CD-BENCH also measures the average access time by performing 100
      random accesses to sectors located in the first 300 MB of the disc.
      Using  a fixed portion of the disc ensures that the result  depends
      only  on	the drive speed and not on the disc size.   If	the  disc
      contains less than 300 MB of data, CD-BENCH skips this test.
	 The  sequence of 100 accesses is only apparently random:  it  is
      always  the  same, every time you perform the test;  in  this  way,
      again, the result depends only on the drive speed.

	 CD-BENCH  interacts  with  the  8253  timer  chip  to	get  high
      resolution timing and, therefore, highly accurate results.

	 The  presence	of  a  disk cache like	SMARTDrive  can  lead  to
      unrealistic  results.   CD-BENCH	temporarily  disables  SMARTDrive
      v4.0+  or  compatible caches (PC-Cache v8.0+ and	the  most  recent
      versions	of Norton Cache are known to be compatible) and  restores
      their  original status before returning to DOS, even if  you  abort
      the  program by pressing Ctrl-Break or ejecting the disc	(I  don't
      lock them so you are free to do as you like).

	 If no parameter is supplied on the command line, CD-BENCH  tests
      all  the available CD-ROM drives; if you want to test only  one  of
      them, just specify its letter.

	 CD-BENCH cannot run in a DOS window under W95 or OS/2: you  have
      to use "plain" DOS.

	 Your feedback is welcome.


      My addresses are:

      E-mail:  pnavato@geocities.com
	       pnavato@poboxes.com
	       Pino Navato, 2:335/225.18  (The Bits BBS, Fidonet)

      WWW:     www.poboxes.com/pnavato
	       (currently forwards to
		 www.geocities.com/SiliconValley/4421)

      Mail:    Pino Navato
	       Via Pittore, 164
	       80046 S.Giorgio a Cremano (NA)
	       ITALY






			   *	 *     *     *	   *