Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!yale!mintaka!mit-eddie!rutgers!bpa!cbmvax!mks
From: mks@cbmvax.commodore.com (Michael Sinz - CATS)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: Performance Rating w/ A2091 and Quantum ProDrive 40S
Message-ID: <9828@cbmvax.commodore.com>
Date: 26 Feb 90 20:14:47 GMT
References: <22452@uflorida.cis.ufl.EDU>
Reply-To: mks@cbmvax.cbm.commodore.com (Michael Sinz - CATS)
Organization: Commodore, West Chester, PA
Lines: 81

In article <22452@uflorida.cis.ufl.EDU> jma@beach.cis.ufl.edu (John 'Vlad' Adams) writes:
>
>I recently received my A2000HD with the Quantum hard drive.  I've been
>relatively happy with the setup (except for needing to populate the
>two meg space on the A2091.)  However, I am not happy with the
>results of DiskSpeed 3.0.  Friends of mine running Kronos 16bit
>non-DMA cards with Segate 28ms drives are reporting faster
>rates.  Shouldn't a DMA card with a 19ms drive perform much better?
>Oh, the background processes running concurrently with this
>run are: ConMan, QMouse, Handshake, NoClick, Bypass_ARP_fr,
>and Bridgeboard [Atime, Amouse, PCDisk.]
>I've run the test with none of the above and the results weren't
>much better.  (At best a few 10k bytes/sec increase -- but not an
>accurate reflection of my normal environment anyways.)
>
>The Quantum is rated at 2.0 megabytes/second asynchronious transfer
>rate in addition to having a 64k cache.  So I doubt the drive slows
>the performance.  So is this standard?  Has Commodore limited a
>speed demon?  Here is the output from Diskspeed 3.0.

Well, the Quantum specs say 2.0 megabytes/second.  And that is the fastest
*ANY* async SCSI-1 device can go.  Also, it is only a "burst" rate that
they quote.  If you happen to not count the time it takes to send the
command to the drive (not on the computer, but on the SCSI) and don't
want too much information and all of it is in the cache then the
Quantum may just happen to send 32K of data at the maximum transfer rate.

As you might know, the drive can only get data to the machine at the
speed the data comes from the disk spinning below the heads.  If you
calculate this from the numbers given on Quantum drives, you will notice
that the sustained data transfer rate can *NOT* be that fast.  In fact,
I would guess that it is on the order of maybe 700K to 850K/second
of RAW data transfer.  (I don't have all of the specs)  Also, the
Quantum drives used variable sectors/track technology that gives them
greater liniar bit density on the outer tracks than other drives.
This also means that the data transfer would be faster in the outer
tracks.  (My Q40 shows ~500K at the inside and ~580K at the outside.)

>
>DiskSpeed 3.0 - Copyright (c) 1989,90 by MKSoft Development
>
>Device:	dh0:
>
>Test Intensity: High  Performance Stress: None
>
>        5 Files/s Create
>       23 Files/s Open/Close
>       65 Files/s Scan
>        8 Files/s Delete
>
>      185 Seek/Read
>
>Buffer Size	512		4096		32768		262144
>---------	---------	---------	---------	---------
>Bytes/s Create	    15229	    85197	   159593	   203129
>Bytes/s Write	    16037	   107686	   315203	   347601
>Bytes/s Read	    35985	   167067	   365094	   520307

Well, there is one other thing you should note:  DiskSpeed != DiskPerf.
DiskSpeed numbers are generated in a more accurate method and are based
on total time (from OS call to return)  With DiskSpeed3.0 on my home
system, with a A2620, fast-rom, and a A2091 and a fast drive (faster
than the Quantums) I get values in the ~800K to ~900K per second
range in the 262144 column and about ~500K to ~550K in the 32768 column.

You will notice a major speed increase with an 2620 or 2630 card, and
even more noticeable with the ROM moved into 32-bit RAM as there is some
file-system and dos.library overhead that is also part of the equation.

>--
>John  M.  Adams    --*--    Professional Student on the six-year plan!      ///
>Internet:  jma@beach.cis.ufl.edu   -or-   vladimir@maple.circa.ufl.edu     ///
>"Houston, we have a negative on that orbit trajectory." Calvin & Hobbs  \\X//

/----------------------------------------------------------------------\
|      /// Michael Sinz -- CATS/Amiga Software Engineer                |
|     ///  PHONE 215-431-9422  UUCP ( uunet | rutgers ) !cbmvax!mks    |
|    ///                                                               |
|\\\///          "I don't think so," said Ren'e Descartes.             |
| \XX/                    Just then, he vanished.                      |
\----------------------------------------------------------------------/