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 087e7c3a for ; Thu, 21 Jun 2018 03:05:58 +0000 (UTC) Received: by minnie.tuhs.org (Postfix, from userid 112) id 8CA47A1562; Thu, 21 Jun 2018 13:05:57 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id B0F509EE0D; Thu, 21 Jun 2018 13:05:30 +1000 (AEST) Received: by minnie.tuhs.org (Postfix, from userid 112) id 1694B9EE0D; Thu, 21 Jun 2018 13:05:29 +1000 (AEST) Received: from vtr.rulingia.com (vtr.rulingia.com [45.77.232.82]) by minnie.tuhs.org (Postfix) with ESMTPS id 664849EE03 for ; Thu, 21 Jun 2018 13:05:28 +1000 (AEST) Received: from server.rulingia.com (ppp59-167-167-3.static.internode.on.net [59.167.167.3]) by vtr.rulingia.com (8.15.2/8.15.2) with ESMTPS id w5L35CgV061500 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 21 Jun 2018 13:05:19 +1000 (AEST) (envelope-from peter@rulingia.com) X-Bogosity: Ham, spamicity=0.000000 Received: from server.rulingia.com (localhost.rulingia.com [127.0.0.1]) by server.rulingia.com (8.15.2/8.15.2) with ESMTPS id w5L357EY091276 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Thu, 21 Jun 2018 13:05:07 +1000 (AEST) (envelope-from peter@server.rulingia.com) Received: (from peter@localhost) by server.rulingia.com (8.15.2/8.15.2/Submit) id w5L357LC091275; Thu, 21 Jun 2018 13:05:07 +1000 (AEST) (envelope-from peter) Date: Thu, 21 Jun 2018 13:05:05 +1000 From: Peter Jeremy To: Paul Winalski Message-ID: <20180621030505.GA89671@server.rulingia.com> References: <20180619204536.GA91748@server.rulingia.com> <20180620050454.GC91748@server.rulingia.com> <20180620081032.GF28267@eureka.lemis.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="ZPt4rx8FFjLCG7dd" Content-Disposition: inline In-Reply-To: X-PGP-Key: http://www.rulingia.com/keys/peter.pgp User-Agent: Mutt/1.10.0 (2018-05-17) Subject: Re: [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" --ZPt4rx8FFjLCG7dd Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 2018-Jun-20 12:33:05 -0400, Paul Winalski wrot= e: >All of the System/360 series except the model 25 used separate channel >processors to perform I/O. The S360 architecture defined separate main CPU and I/O channel processors and the actual implementation varied between models. IBM stressed the compatibility between models so it can be difficult to determine what the actual implementation did in hardware vs microcode. At least the model 30 also emulated the channel processor using the main CPU. [1] confirms this for the multiplexor[2] channels and implies it for the selector[3] channels. The "CPU interference factors" in [5](p65) suggest the model 50 also emulated the channel processors. The idea of separate I/O processors was also used in the CDC6600. >term "memory") completely independently from the CPU. The S/360 model >25 was the last of the 360 series and was really a 16-bit minicomputer >microprogrammed to execute the S/360 instruction set. Note that most S360 machines were microcoded with the native ALU size varying between 8 and 32 bits. The model 25 was also the only S360 with writable microcode and there was a microcoded APL implementation for it so it "natively" executed APL. I'm not sure if there were any other novel microcode sets for it. Going back to Greg's question of actual I/O performance: A model 50 could support 3 selector channels, with a nominal rate of 800kBps each[6]. Since each selector channel could only perform a single I/O operation at a time, I believe the actual rate was effectively limited to the fastest device on the channel - which [5] indicates was 340kBps for a 7340-3 Hypertape at 3022bpi. That implies a total of 1020kBps of I/O. The "CPU interference" indicates that each byte transferred blocked the CPU for 0.95us, so 1020kBps of I/O would also steal 97% of the CPU-storage bandwidth. [1] http://bitsavers.org/pdf/ibm/360/funcChar/GA24-3231-7_360-30_funcChar.p= df [2] "multiplexer" channels were used for low speed devices - card readers, card punches, printers, serial communications. [3] "selector" channels were used for high speed devices - tape, DASD[4] [4] Direct Access Storage Device - IBM speak for "disk" [5] http://bitsavers.org/pdf/ibm/360/funcChar/A22-6898-1_360-50_funcChar_19= 67.pdf [6] https://www-03.ibm.com/ibm/history/exhibits/mainframe/mainframe_PP2050.= html --=20 Peter Jeremy --ZPt4rx8FFjLCG7dd Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQKTBAEBCgB9FiEE7rKYbDBnHnTmXCJ+FqWXoOSiCzQFAlsrFeFfFIAAAAAALgAo aXNzdWVyLWZwckBub3RhdGlvbnMub3BlbnBncC5maWZ0aGhvcnNlbWFuLm5ldEVF QjI5ODZDMzA2NzFFNzRFNjVDMjI3RTE2QTU5N0EwRTRBMjBCMzQACgkQFqWXoOSi CzSyhA//ZEvri9+HM92q8EGdBkjbUiuM51c3pP7qk7+/gO3kafHBWEtkbIfRSaJP ZOpXW5ieY3ytWnoiq0GBm3hs0Z7sNUaA0kwCbaoG3IRzX8LTD2b8SQFgKniiDDt4 aKaKId9ndvP0vEwBjxjDBXo8osBxPp4VgvuxEw/2tbChiAu0/HNNvyi44WNmATtL 1kQMF+up+HPZKXrsF3wzo7kG7B40JPXQ9ba9lI+fzjoKnXRZYtWn5dZlaWFurJ1m pZFT4RsJwdnGY7tayCTLLUkwIIJqq+f6hLf/EAnd3nHtUgUtszM8zGiNRlt1kKwx um/W56T5iP4rwLuvezIrDVANKBS0zvn2WT5+cIEIZjAOgY75/qOF26ocZJXfZ1gO xeLbSZmpvuZ9AeGOFIGUw5XxYMroNY19tkWLQQrBXb1Dzzb+4FTiRCoxubxgGh5u nmid0ZcG2NyXEqz/zUhM+RZbdNcsJZxuke3bsDGqrMxY1SEvwnuO+WyNUhADdENY k9C2OgJGzooVIfMwWRnR5ZBnzIS+gYa2kQdY6NwjtRU6TYVT3f1u+JMyz/3b2g35 s/7WMG+pa79RM67skZXRH4bUHUUbZpa6Ayg14QhltPyOGiRWKHUQwGb3XrjjjaGK Z2qQIOGPY0MB2wRUUBFsBOyehPz+oQVHTkllCmOu0vH3dBsIECA= =D+Km -----END PGP SIGNATURE----- --ZPt4rx8FFjLCG7dd--