From owner-freebsd-alpha Sun Oct 10 23:10:48 1999 Delivered-To: freebsd-alpha@freebsd.org Received: from overcee.netplex.com.au (overcee.netplex.com.au [202.12.86.7]) by hub.freebsd.org (Postfix) with ESMTP id 3832714DA2 for ; Sun, 10 Oct 1999 23:10:44 -0700 (PDT) (envelope-from peter@netplex.com.au) Received: from netplex.com.au (localhost [127.0.0.1]) by overcee.netplex.com.au (Postfix) with ESMTP id 1FBDC1CCE; Mon, 11 Oct 1999 14:10:43 +0800 (WST) (envelope-from peter@netplex.com.au) X-Mailer: exmh version 2.0.2 2/24/98 To: Michael Robinson Cc: dfr@nlsystems.com, freebsd-alpha@freebsd.org Subject: Re: How 64-bit is Alpha FreeBSD? In-reply-to: Your message of "Mon, 11 Oct 1999 13:41:53 +0800." <199910110541.NAA03545@netrinsics.com> Date: Mon, 11 Oct 1999 14:10:43 +0800 From: Peter Wemm Message-Id: <19991011061043.1FBDC1CCE@overcee.netplex.com.au> Sender: owner-freebsd-alpha@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org Michael Robinson wrote: > Doug Rabson writes: > >We support a 42 bit user address space right now. This is a hardware > >limitation for older alphas but could be changed for newer hardware which > >could probably extend it to 55 bits. > > Thanks. > > Does that mean, theoretically speaking, that if I were running FreeBSD on an > Alpha with sufficient kernel memory, and 2 terabytes of data files, I could > mmap the whole 2 terabytes into one process? I'm pretty sure the FreeBSD VM system is limited to 1TB - ie: 512 bytes times 2^31 - to enable use of native types rather than synthetic 64 bit types in the kernel in performance critical areas. I'm not sure how this relates to the Alpha though since it has 'long' == 64 bit and it might be 512 x 2^63. I'm pretty sure I've seen int32_t types instead of 'long' so I wouldn't count on it. Cheers, -Peter To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-alpha" in the body of the message