From owner-freebsd-hackers@FreeBSD.ORG Fri Mar 27 11:59:15 2015 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id D4AE3C26 for ; Fri, 27 Mar 2015 11:59:15 +0000 (UTC) Received: from mail-qc0-x233.google.com (mail-qc0-x233.google.com [IPv6:2607:f8b0:400d:c01::233]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 8B71374E for ; Fri, 27 Mar 2015 11:59:15 +0000 (UTC) Received: by qcbjx9 with SMTP id jx9so14023324qcb.0 for ; Fri, 27 Mar 2015 04:59:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:from:date:message-id :subject:to:cc:content-type; bh=uOPrhCGoyX+y/WWn5U8SOmO6TnbNnClpDLH/5nAdyss=; b=QGJveNk9uPMD3l7RZ5mMb7ddzvEDJwIfW61ektxfsVwSD5+S0z+iCMf3yxTxNstQY0 hv/Wfzbu3gLIwxCJcowyc6XkyIJzooqXXF5XvERrQC6W5e6Q5T8dR4o/z591gT8U4whz FjZZVMEO55GwXSNFBcsNnmtvKxkU44+uVMj29ZnWCIvjME7utm2UaosBvpnoNtgiMPkb dKWID8YOdqdYuK0IZzZLs5VmOM9ngtqyQtzlB4A43ytBKAnX3SUnnVU/MbsmBARsuKBC MwxN+cTQ1fsN716GaVV2CLi1mYCRp5MeOyX6YPG31yiv9ClPTFDpACZG24yCOomGPDJ7 w/aw== X-Received: by 10.55.42.85 with SMTP id q82mr2118946qkh.48.1427457554755; Fri, 27 Mar 2015 04:59:14 -0700 (PDT) MIME-Version: 1.0 Sender: mozolevsky@gmail.com Received: by 10.140.91.112 with HTTP; Fri, 27 Mar 2015 04:58:34 -0700 (PDT) In-Reply-To: References: From: Igor Mozolevsky Date: Fri, 27 Mar 2015 11:58:34 +0000 X-Google-Sender-Auth: 7kFE3hGcHq4E2yETPyfsNaPyi8E Message-ID: Subject: Re: Seagate Archive HDD To: Mark Martinec Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.18-1 Cc: Hackers freeBSD X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 27 Mar 2015 11:59:16 -0000 On 27 March 2015 at 11:05, Mark Martinec wrote: > 2015-03-27 09:56, Igor Mozolevsky wrote: > >> On 27 March 2015 at 08:36, Wojciech Puchar wrote: >> >>> what is a difference between "video recording" and normal SATA drives? >>> except pricing of course. >>> >> >> The "video recording" HDDs have no, among other things, internal "long >> recovery" mechanisms (hence the price) because unlike "data", "video" >> doesn't really care if small part of a frame gets corrupted on disk=E2= =80=A6 >> > > > AV disks support ATA streaming command set, are designed to last > in high temperature always-on streaming digital AV environments, are > silent, with Preemptive Wear Leveling (PWL) (the drive arm frequently > sweeps across the disk to reduce uneven wear on the drive surface > common to audio video streaming applications) > > (paraphrased from WD docs) I was saying why the AV disks are not a good idea for general purpose data storage, not what the general idea was=E2=80=A6 HSGT have a whitepaper "for the masses" on the topic: "=E2=80=A6 In AV applications, it may be better to have some small segment of incorrect data delivered in the stream than to have a long delay. Short delays may result in the loss of only a few pixels*. A long delay in the data stream would result in the loss of a larger block of data, which would be noticeable to a viewer. A new Streaming Command Set has been developed for ATA drives, which allows AV products to change drive behavior to meet AV system requirements=E2=80=A6" [1] 1. http://www.hgst.com/tech/techlib.nsf/techdocs/FEF3B52BFE9A054586256E66005AA= 389/$file/WP_AV_25March.pdf --=20 Igor M.