From owner-freebsd-scsi Wed Feb 27 12:11:24 2002 Delivered-To: freebsd-scsi@freebsd.org Received: from rwcrmhc54.attbi.com (rwcrmhc54.attbi.com [216.148.227.87]) by hub.freebsd.org (Postfix) with ESMTP id E916637B402 for ; Wed, 27 Feb 2002 12:11:21 -0800 (PST) Received: from gateway.posi.net ([12.236.90.177]) by rwcrmhc54.attbi.com (InterMail vM.4.01.03.27 201-229-121-127-20010626) with ESMTP id <20020227201121.XZDC1214.rwcrmhc54.attbi.com@gateway.posi.net>; Wed, 27 Feb 2002 20:11:21 +0000 Received: from localhost (kbyanc@localhost) by gateway.posi.net (8.11.6/8.11.6) with ESMTP id g1RKBKT08384; Wed, 27 Feb 2002 12:11:20 -0800 (PST) (envelope-from kbyanc@posi.net) X-Authentication-Warning: gateway.posi.net: kbyanc owned process doing -bs Date: Wed, 27 Feb 2002 12:11:19 -0800 (PST) From: Kelly Yancey To: gemorga2 Cc: scsi@FreeBSD.ORG Subject: RE: IDE vs. SCSI partition and slice limits In-Reply-To: <3C7D3F5E@zathras> Message-ID: <20020227120524.W8086-100000@gateway.posi.net> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-scsi@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org On Wed, 27 Feb 2002, gemorga2 wrote: > So is that 30 slices inside a PC style partition or thirty partitions (as DOS > considers "primary" partitions). I heard (probably incorrectly) that a "DOS" > readable partition table has only 4 "slots" for "primary" partitions. With > extended partitions I know you can have lots of "logical drives". > The Master Boot Record only has room for 4 partitions (FreeBSD "slices"). However, one of these partitions can be marked as an extended partition which begins with another MBR, again with 4 partitions. In theory one can create a tree structure describing partitions this way, however in practive it must be a list (degenerate tree). Nonetheless, as Bruce pointed out, one can have large numbers of partitions (limited only be disk space), but only a maximum of 4 of them can be described by the MBR itself. Any tool that only knows how to work with the MBR is limited to manipulating those 4 records. FreeBSD itself, can deal with additional partitions as defined in the extended partitions' MBR records also. Again, "partition" = "slice" in FreeBSD parlance. Kelly kbyanc@{posi.net,FreeBSD.org} To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message