From mboxrd@z Thu Jan 1 00:00:00 1970 From: Saswat Praharaj Subject: Re: read vs write Date: Mon, 25 Jul 2005 17:10:22 +0530 Message-ID: References: <42E4BFC1.7070905@stesmi.com> Reply-To: Saswat Praharaj Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from wproxy.gmail.com ([64.233.184.193]:19597 "EHLO wproxy.gmail.com") by vger.kernel.org with ESMTP id S261227AbVGYLkW convert rfc822-to-8bit (ORCPT ); Mon, 25 Jul 2005 07:40:22 -0400 Received: by wproxy.gmail.com with SMTP id 37so946565wra for ; Mon, 25 Jul 2005 04:40:22 -0700 (PDT) In-Reply-To: <42E4BFC1.7070905@stesmi.com> Content-Disposition: inline Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Stefan Smietanowski Cc: linux-ide@vger.kernel.org yups I meant MBps ..thanks for correcting me . However, I dont agree with your ford/road example. I just checked the product specification of STA340016A (seagate) .=20 Here is what they claim :=20 [ This manual describes the functional, mechanical and interface speci= fi- 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 pe= r second) using Ultra DMA mode 5 ] I have found average seek time is little faster (around 1ms) for read than write. Still that doesn't justify the write speed of 15-20 MBps and 55-60 MBps for read. Can anyone help me understading how/why write is different than read. Thanks and Regards, Saswat On 7/25/05, Stefan Smietanowski wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 >=20 > Hi Saswat. >=20 > > Moreover, I am wondering if I could achieve the 100Mbps read speed = as > > claimed by different vendors.For me , It should ideally be 100 Mbps= as > > I am using a 80 conductor cable and UDMA 5.Why then I am getting 58 > > Mbps max . . >=20 > If you mean Mbps then you are already above it. 100Mbps =3D 12.5MB/s > give or take and both speeds are above that. > I guess you probably mean 100MB/s though and that is only what > the cable can take. >=20 > If you take a T-ford onto the highway - can you go 130Km/h in it? >=20 > No, the road is rated at 130Km/s but the car can't go that fast. >=20 > Same here, the standard says you can transfer 100MB/s over the cable > but the disk isn't fast enough to be able to transfer that fast. >=20 > // Stefan > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.1 (MingW32) >=20 > iD8DBQFC5L/BBrn2kJu9P78RAkXKAJ4vc/xQ0Z8mA1ddo79+wC6NCFe5VACgl+j+ > ceP+as8dx0uZs2W6xaYiMVc=3D > =3DOf1/ > -----END PGP SIGNATURE----- >