whatsnew-apr02,2000

Linux磁盘测试的源代码,测试磁盘的读写性能

April 3rd, 2000 Robin Miller

	The following changes were made to 'dt' Version 13.10:

    13.6 -> 13.7

     o	In HandleMultiVolume(), reset the exit status to SUCCESS, since
	this got set to END_OF_FILE earlier.  Failure to do this meant we
	exited with an END_OF_FILE (254) status on the read pass instead
	of SUCCESS (0).

    13.7 -> 13.8

     o	Fixed parsing of flags=direct for Tru64 Clusters.
     o	Don't permit passes=0, as this caused segmentation fault.
     o	Don't create unique file names with procs= to named FIFO.

    13.8 -> 13.9

     o	Added "capacity=value" option, and ignore read errors in
	FindCapacity() called for iotype=random option.
     o	Fixed problem with "position=value" truncating file position
	to 32 bits, since the file offset may be a 64-bit entity (off_t).
     o	Improved file position functions to provide better debug output.
	Also, only scale the random position upwards by the device size
	every other record, so low blocks gets utilized more often.
	Note: These changes degrade random I/O performance slightly.
	[ for "best" performance, all debug really needs omitted, but
	  currently there's no way to permit this (future consideration). ]
     o	Fixed exit status when "runtime=" option used.  This exit path
	only looked at error_count to set FAILURE exit status, while
	non-runtime exit path looked at exit_status variable.

	Note: The ignoring of read error in FindCapacity(), was added
	for reading ATAPI CD's on Linux, since this driver does *not*
	properly handle seek/reads past the end of media.  The last good
	read gets used when the read error occurs.  Use "capacity=value"
	to avoid this error condition. [ occurs on RedHat Linux V6.1 ]

    13.9 -> 13.10

     o	Minor change for QNX operating system.  Stat'ing block devices
	returns the number of blocks in st_size field, which needed scaled
	by the block size (512 bytes), before setting the random data limit
	and disk capacity.  This only affected random I/O tests.

	Within Compaq, the updated 'dt' kits are located @ URL:

		http://www.zk3.dec.com/~rmiller/dt.html

	External to Compaq, you can obtain 'dt' kits from URL:

		http://www.bit-net.com/~rmiller/dt.html

Cheers,
Robin