From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Smietanowski Subject: Re: read vs write Date: Mon, 25 Jul 2005 14:36:22 +0200 Message-ID: <42E4DCC6.7010302@stesmi.com> References: <42E4BFC1.7070905@stesmi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mxfep01.bredband.com ([195.54.107.70]:53904 "EHLO mxfep01.bredband.com") by vger.kernel.org with ESMTP id S261152AbVGYMaL (ORCPT ); Mon, 25 Jul 2005 08:30:11 -0400 In-Reply-To: Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Saswat Praharaj Cc: linux-ide@vger.kernel.org -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Saswat Praharaj wrote: > yups I meant MBps ..thanks for correcting me . >=20 > However, I dont agree with your ford/road example. >=20 > I just checked the product specification of STA340016A (seagate) .=20 >=20 > Here is what they claim :=20 >=20 > [ This manual describes the functional, mechanical and interface spe= cifi- > cations for the ST380021A, ST360021A, ST340016A and ST320011A. > These drives provide the following key features: > =B7 7,200-RPM spindle speed and 2-Mbyte buffer combine for superior > desktop performance > =B7 High instantaneous (burst) data-transfer rates (up to 100 Mbytes = per > second) using Ultra DMA mode 5 ] Yes, burst is transfer speed not speed from the platter. The drive has a cache (2MB). From that cache you can transfer at 100MB/s, not from the platter sadly enough. Even those 10kRPM drives don't do 100. So road =3D=3D cable =3D=3D from cache in a sense (assuming the cache c= an do 100MB/s). T-Ford =3D platter. I wish it was different but it's not. I mean, a SATAII-300 - do you honestly believe you can read and write att 300MB/s to that drive? To/From Cache : maybe. Platter : No way. But if you read the same data 10 times in a row (size=3D1MB let's say) then yes, you should be seeing 100MB/s or somewhere close depending on where your controller is, how saturated the bus is, etc. // Stefan -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (MingW32) iD8DBQFC5NzGBrn2kJu9P78RAikFAJ0Tg073q3hsBb6bG9ucwOqYLaxBuQCfQWqk gYjK8WJ/at4uNJhks+uh3RA=3D =3DcNWZ -----END PGP SIGNATURE-----