Date: Mon, 11 Oct 1999 14:10:43 +0800 From: Peter Wemm <peter@netplex.com.au> To: Michael Robinson <robinson@netrinsics.com> Cc: dfr@nlsystems.com, freebsd-alpha@freebsd.org Subject: Re: How 64-bit is Alpha FreeBSD? Message-ID: <19991011061043.1FBDC1CCE@overcee.netplex.com.au> In-Reply-To: Your message of "Mon, 11 Oct 1999 13:41:53 %2B0800." <199910110541.NAA03545@netrinsics.com>
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Michael Robinson wrote: > Doug Rabson <dfr@nlsystems.com> 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
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