Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!uflorida!gatech!udel!mmdf From: thad%cup.portal.com%cunyvm.cuny.edu@cunyvm.cuny.edu Newsgroups: comp.sys.amiga Subject: Re: 2090A and DMA (was: Re: 2000-and-1 expansion box) Message-ID: <4490@louie.udel.EDU> Date: 4 Oct 88 03:57:12 GMT Sender: mmdf@udel.EDU Lines: 57 Received: from CUNYVM by CUNYVM.BITNET (Mailer X2.00) with BSMTP id 6657; Mon, 03 Oct 88 23:54:49 EDT Received: from UDEL.EDU by CUNYVM.CUNY.EDU (IBM VM SMTP R1.1) with TCP; Mon, 03 Oct 88 23:54:45 EDT Received: from Louie.UDEL.EDU by Louie.UDEL.EDU id aa16810; 3 Oct 88 22:16 EDT Received: from USENET by Louie.UDEL.EDU id aa16625; 3 Oct 88 22:08 EDT From: thad%cup.portal.com@cunyvm.cuny.edu Subject: Re: 2090A and DMA (was: Re: 2000-and-1 expansion box) Message-ID: <4484@louie.udel.EDU> Date: 4 Oct 88 02:07:26 GMT To: amiga-relay@UDEL.EDU Sender: amiga-relay-request@UDEL.EDU Received: from CUNYVM by CUNYVM.BITNET (Mailer X2.00) with BSMTP id 5896; Mon, 03 Oct 88 21:54:43 EDT Received: from UDEL.EDU by CUNYVM.CUNY.EDU (IBM VM SMTP R1.1) with TCP; Mon, 03 Oct 88 21:54:40 EDT Received: from Louie.UDEL.EDU by Louie.UDEL.EDU id aa13333; 3 Oct 88 19:24 EDT Received: from USENET by Louie.UDEL.EDU id aa13142; 3 Oct 88 19:17 EDT From: thad@cup.portal.com Subject: Re: 2090A and DMA (was: Re: 2000-and-1 expansion box) Message-ID: <9670@cup.portal.com> Date: 2 Oct 88 23:55:34 GMT Organization: The Portal System (TM) XPortal-User-Id: 1.1001.2826 To: amiga-relay@UDEL.EDU Sender: amiga-relay-request@UDEL.EDU Re: Steve Beat's request for ideas addressing massive storage devices ... Present SCSI (for example) uses 32-bits to address a logical block. Assuming one's block size is 512 bytes, this would permit one to "reach" 2 TeraBytes (2^12). Given the possibility of, say, optical media having capacities in that ballpark within a few years, the problem is not moot. At the MINIMUM, I see the need for 48 bits of addressing such devices; at the least would be 32-bits for a "block" and 16 bits for a byte-offset within the block. As a suggestion, I would recommend contacting the (known) developers of such large storage devices now and ask them how they expect their devices to be incorporated and used in computing systems. As a matter of general interest, the ANSI X3T9.2 SCSI committee operates a BBS system dedicated to the discussion of such matters as they pertain to ANSI standards and the manufactuers of equipment expected to be in compliance with the standards. The SCSI-2 standard is nearly completed (for review), and SCSI-3 is in the planning stages. John Lohmeyer (the Chairman of X3T9.2) recently informed me of some exciting new developments on the horizon. Since CBM has a need to also be compliant with future standards, I'd recommend applying for an account on the SCSI BBS; contact me (email) if you'd like additional info. Thad Floryan [thad@cup.portal.com (OR) ...!sun!portal!cup.portal.com!thad]