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{\subject Speed Test Description}{\author }{\doccomm Desribes the DOS and WINdows speed tests for determining the maximum Kb/sec a drive(r) can deliver data from a CDROM disc.}{\operator Michael Edwards}{\creatim\yr1990\mo8\dy4\hr10\min12}
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\fs20 {\b\f2\fs16 Speed Tests - Microsoft MS-DOS CD-ROM Extensions Version 2.20
\par
\par }}{\footer \pard\plain \qc\sl240 \fs20 {\b\f2\fs16 Speed Tests - Copyright (C) Microsoft Corp. 1990. All rights reserved - page }{\field{\*\fldinst {\b\f2\fs16 page}}{\fldrslt {\b\f2\fs16 3}}}{\b\f2\fs16
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\par }{\headerf \pard\plain \qc\sl240 \fs20 {\b\f2\fs28 Microsoft MS-DOS CD-ROM Extensions
\par Speed Tests
\par 15 August 1990
\par
\par }}{\footerf \pard\plain \qc\sl240 \fs20 {\b\f2\fs16 Speed Tests - Copyright (C) Microsoft Corp. 1990. All rights reserved - page }{\field{\*\fldinst {\b\f2\fs16 page}}{\fldrslt {\b\f2\fs16 1}}}{\b\f2\fs16
\par }\pard\plain \s242\tqc\tx4320\tqr\tx8640 \fs20
\par }\pard\plain \qj\sl240 \fs20 {\fs22
This document describes the file transfer tests DOSSPEED and WINSPEED provided on DISK1. These programs measure the rate that data can be read from the CD-ROM, with DOSSPEED measuring this transfer rate in the DOS environment and WINSPEED in the Windows
environment.
\par
\par }{\plain \b The Need for Speed Tests
\par }{\fs22
\par One thing that distinguishes CD-ROM media from other media is the nature in which the data is provided, that is, it can be viewed as a "data stream." The fact that an application can depend upon the data coming
off the disc at a guaranteed rate of 150Kb/second provides unique advantages. Unfortunately there are various problems, which in practice can limit throughput, creating the situation that while the transfer rate on any one drive is fairly constant, it is
often less 150Kb/second, sometimes much less. If an application prepares a data stream to be played off the disc it must be able to make certain assumptions about the rate at which the data stream will be provided. If the designers of the application d
ec
ide to support a drive which cannot maintain 150Kb/second, then they have to make a decision about what minimum transfer rate to support, and to do this they need information about sustainable transfer rates. Therefore the sustainable transfer rate avai
lable on your drive is important information which should be determined and provided to your customers.
\par
\par }{\plain \b Description of DOS Speed Test
\par }{\fs22
\par }Usage information (This is also available by typing "DOSSPEED -?"):
\par {\fs22
\par }\pard DOSSPEED [pathname] [-r:X] [-b:X] [-p:X] [-f] [-t]
\par
\par where:
\par
\par \pard \fi-1260\li1260\tx990 [pathname]\tab \tab Path and name of file to test.\line
\par -r\tab \tab Sets the transfer rate in bytes/sec (150Kb/sec default).\line
\par -b:[blocksize]\tab Sets the blocksize (bytes per read request), which must be from 1 to 65534 (16Kb default).\line
\par -p\tab \tab
Specifies the number of bytes used to prime the buffer. The number of bytes range from 1 to 65534 with a default of 0. This parameter allows a read-ahead buffer to fill up before the transfer rate timing actually begins. This is useful when testing tran
sfer rates approaching the maximum rate available for CD-ROM drives.\line
\par -f\tab \tab Performs a straight speed test with no delays, that is, it doesn't calculate how much time was spent blocked in the synchronous read requests.\line
\par -t\tab \tab Causes terse output in the following format (useful for input to a spreadsheet):\line \line <% time blocked>
\par \pard \fi-1440\li1440\tx990
\par \pard \page
\par DOSSPEED.EXE determines several characteristics of a CD-ROM drive. The command line options give three degrees of freedom. Some suggested performance curves are:
\par
\par \tab Transfer rate as a function of blocksize
\par
\par \tab Transfer rate as a function of primer bytes
\par
\par \tab CPU usage (% time blocked) as a function of blocksize
\par
\par \tab CPU usage (% time blocked) as a function of expected transfer rate
\par
\par \pard \fi-720\li720 \tab CPU usage (% time blocked) as a function of both blocksize and expected transfer rate
\par \pard
\par It is important to consider the best use of a CD-
ROM drive. Applications require sustainable transfer rates with suitable CPU bandwith available to complete various tasks between contiguous read requests. By considering the CPU usage as a function of both blocksize and expected transfer rates, a buffe
ring solution may be determined. Always select a relatively large file for conducting DOSSPEED tests in order to reduce the small degree of error in the timing loop.
\par \pard \qj\sl240 {\fs22
\par }{\plain \b Description of Windows Speed Test
\par }\pard \sl240 {\fs22
\par }\pard {\fs22
This speed test operates as a Windows application. The Windows speed test pops up a window with a standard Files/Directories I/O dialog. The tester selects a file on the CD-ROM disc and, like the DOS test, it keeps track of how much time elapses in read
ing the entire file, reports the average transfer rate, how many total bytes were read, and how many bytes were read by each request. Unlike the DOS based test, this test doesn't analyze CPU bandwidth available between read requests.
\par
\par To run this test select Run from the File menu, and execute the command: WINSPEED.EXE.
\par
\par }}