From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: tuhs-bounces@minnie.tuhs.org X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham autolearn_force=no version=3.4.1 Received: from minnie.tuhs.org (minnie.tuhs.org [45.79.103.53]) by inbox.vuxu.org (OpenSMTPD) with ESMTP id 3be7d7de for ; Wed, 20 Jun 2018 08:11:10 +0000 (UTC) Received: by minnie.tuhs.org (Postfix, from userid 112) id 9BFD4A17DE; Wed, 20 Jun 2018 18:11:09 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id 50138A17C2; Wed, 20 Jun 2018 18:10:39 +1000 (AEST) Received: by minnie.tuhs.org (Postfix, from userid 112) id 47AC6A17C2; Wed, 20 Jun 2018 18:10:35 +1000 (AEST) Received: from www.lemis.com (www.lemis.com [208.86.226.86]) by minnie.tuhs.org (Postfix) with ESMTP id 9B047A17C0 for ; Wed, 20 Jun 2018 18:10:34 +1000 (AEST) Received: from eureka.lemis.com (lemis.com [192.109.197.81]) by www.lemis.com (Postfix) with ESMTP id 6E7431B72838; Wed, 20 Jun 2018 08:10:33 +0000 (UTC) Received: by eureka.lemis.com (Postfix, from userid 1004) id 4EAB74494B5; Wed, 20 Jun 2018 18:10:32 +1000 (AEST) Date: Wed, 20 Jun 2018 18:10:32 +1000 From: Greg 'groggy' Lehey To: Warner Losh Message-ID: <20180620081032.GF28267@eureka.lemis.com> References: <20180615152542.E1EC918C08C@mercury.lcs.mit.edu> <20180619204536.GA91748@server.rulingia.com> <20180620050454.GC91748@server.rulingia.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="xaMk4Io5JJdpkLEb" Content-Disposition: inline In-Reply-To: Organization: LEMIS, 29 Stones Road, Dereel, VIC, Australia Phone: +61-3-5346-1370, +61-3-5309-0418 Mobile: 0401 265 606. Use only as instructed. WWW-Home-Page: http://www.lemis.com/grog X-PGP-Fingerprint: 9A1B 8202 BCCE B846 F92F 09AC 22E6 F290 507A 4223 User-Agent: Mutt/1.6.1 (2016-04-27) Subject: [TUHS] Old mainframe I/O speed (was: core) X-BeenThere: tuhs@minnie.tuhs.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: The Unix Heritage Society mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: The Eunuchs Hysterical Society Errors-To: tuhs-bounces@minnie.tuhs.org Sender: "TUHS" --xaMk4Io5JJdpkLEb Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Tuesday, 19 June 2018 at 23:41:41 -0600, Warner Losh wrote: > On Tue, Jun 19, 2018 at 11:04 PM, Peter Jeremy wrote: > >> On 2018-Jun-20 08:55:05 +1000, David Arnold wrote: >>> Does the screen count as I/O? >> >> I was thinking about that as well. 1080p30 video is around 2MBps >> as H.264 or about 140MBps as 6bpp raw. The former is negligible, >> the latter is still shy of the disparity in CPU power, especially >> if you take into account the GPU power needed to do the decoding. >> >>> I???d suggest that it???s just that the balance is (intentionally) quite >> different. If you squint right, a GPU could look like a channelized I/O >> controller. >> >> I agree. Even back then, there was a difference between >> commercial-oriented mainframes (the 1401 and 360/50 lineage - which >> stressed lots of I/O) and the scientific mainframes (709x, 360/85 - >> which stressed arithmetic capabilities). > > So what could an old mainframe do as far as I/O was concerned? Google > didn't provide me a straight forward answer... Looking at something like the IBM 370 series (mid-1970s), I/O was performed by the channels, effectively separate processors with a very limited instruction set. Others, like the UNIVAC 1100 series, could perform I/O directly or via separate processors. This was similar on the /360, but very different on the 1401. In each case, from my recollection, main memory and the peripheral were the bottleneck. For the UNIVAC 1108 (1965, the one of which I have the best recollection), memory was 36 bits every 750 ns, and you could expect it to be interleaved at least 2 ways, so you could transfer data across two channels to a FH 432 drum at in the order of 2.5 MW/s. This could lead to underruns depending on what else was going on in the system. Other peripherals were slower, so this would have been about the maximum. Greg -- Sent from my desktop computer. Finger grog@lemis.com for PGP public key. See complete headers for address and phone numbers. This message is digitally signed. If your Microsoft mail program reports problems, please read http://lemis.com/broken-MUA --xaMk4Io5JJdpkLEb Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iEYEARECAAYFAlsqC/gACgkQIubykFB6QiPLMQCfd31/TUpiLEIqQ9J3DovfCg+P hxQAmwazjfBJdN95S+HR7jwtpJOPqoBy =z4q0 -----END PGP SIGNATURE----- --xaMk4Io5JJdpkLEb--