From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=5.0 tests=DKIM_INVALID,DKIM_SIGNED, MAILING_LIST_MULTI autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 14148 invoked from network); 13 Dec 2022 16:32:11 -0000 Received: from minnie.tuhs.org (50.116.15.146) by inbox.vuxu.org with ESMTPUTF8; 13 Dec 2022 16:32:11 -0000 Received: from minnie.tuhs.org (localhost [IPv6:::1]) by minnie.tuhs.org (Postfix) with ESMTP id 282FB4241F; Wed, 14 Dec 2022 02:31:48 +1000 (AEST) Received: from mail-oi1-f175.google.com (mail-oi1-f175.google.com [209.85.167.175]) by minnie.tuhs.org (Postfix) with ESMTPS id ECEBD4240D for ; Wed, 14 Dec 2022 02:31:44 +1000 (AEST) Received: by mail-oi1-f175.google.com with SMTP id r11so237082oie.13 for ; Tue, 13 Dec 2022 08:31:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=iitbombay-org.20210112.gappssmtp.com; s=20210112; h=to:references:message-id:content-transfer-encoding:cc:date :in-reply-to:from:subject:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=A7PJ71GaY77wX1DSjtz33ErRKPDDNCHQk1NqYZBhbzA=; b=aAeFa2iyTqMZSB3Y8Gb3AJkO+S1FMjVbW8Mcz1ewhD2iGzoOiU4yWPn08KwDMCZufX 1lom1zRWwhd2tBcAh9w4xxlfGvrKN5NLUPTWcGwa1juVRNLASwewLSx+2a920triIbfD Ebu8pOedBM1KacOLLPncfPnXSPz/2XxXtf+vgoS4d+ylQpztiesRCYYk4WLQfkBMf72w Jps9aiFIkhS4opeZPfD7FrgiSASKz8VEVBSKw0l2cSgG9Kqd7LJgIBYBZ+GjbcCmaG/F W8S0wVt93Mvl6y8ts+ytSC+xiDz0G1KQQ+ovVUxl7kz5PXDZduyAAYxqfzy4YYy0P61h G6pA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=to:references:message-id:content-transfer-encoding:cc:date :in-reply-to:from:subject:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=A7PJ71GaY77wX1DSjtz33ErRKPDDNCHQk1NqYZBhbzA=; b=XPSs8T+MuJhULi1tU0b3WQQhLnLCTHI5gG+4LxhDavElHIn27Vn+5KkefzcEu+o1on BB1E/cejcOVeY/B/7CrJUneZwlSS+WGmIMthRmjwShcKMr51GpTtrtGlAh5VPsBDsSPf UlYhlikJt+ceOVooR13Qbj+POTIxqrAQWn0/Wi1q9BEdSvPxW6ca6SsXzpFcd7kDiP/k Ehe9rFvqwA284r26t3BxjOa/xchN6lVPj7smjdLboBxFtP0ECBFlxaod7HRSuQX8nh4N DCSOm2+3voJMP1lYNAyKOb+oXovwQdhicXZpkrCzYZEkslk06qUKkhL7fV/GTFJ2O82k it9A== X-Gm-Message-State: ANoB5pmJIzHcZIBDkW+IamluoEiJEM2VOKgr0vTNejPk/N477E/kmeu7 Bk/0rd5FNe4ecEUgQf3RM4r7AwgOQyu+VQ1K X-Google-Smtp-Source: AA0mqf5/MKMUSwB1dqJ2keW3xtwP0nlj6N5zf3Rv9+jmeniwMzY4f2hbV0DwTjquBMx19qllI+v2aw== X-Received: by 2002:aca:dac2:0:b0:35b:d7dc:9f25 with SMTP id r185-20020acadac2000000b0035bd7dc9f25mr8973833oig.32.1670949044203; Tue, 13 Dec 2022 08:30:44 -0800 (PST) Received: from smtpclient.apple (107-215-223-229.lightspeed.sntcca.sbcglobal.net. [107.215.223.229]) by smtp.gmail.com with ESMTPSA id i9-20020a9d53c9000000b00666a5b5d20fsm1345086oth.32.2022.12.13.08.30.43 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Tue, 13 Dec 2022 08:30:43 -0800 (PST) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3731.200.110.1.12\)) From: Bakul Shah In-Reply-To: <20221213161442.7A96422139@orac.inputplus.co.uk> Date: Tue, 13 Dec 2022 08:30:32 -0800 Content-Transfer-Encoding: 7bit Message-Id: <7373D902-BC96-4149-925F-FC6F29BC2290@iitbombay.org> References: <29888CC6-CA23-4361-BC9C-1B8A775C8DA9@iitbombay.org> <20221213161442.7A96422139@orac.inputplus.co.uk> To: Ralph Corderoy X-Mailer: Apple Mail (2.3731.200.110.1.12) Message-ID-Hash: FWHML6IP3HKBER3IININ43KFMDHP7ROF X-Message-ID-Hash: FWHML6IP3HKBER3IININ43KFMDHP7ROF X-MailFrom: bakul@iitbombay.org X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; header-match-tuhs.tuhs.org-0; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: tuhs@tuhs.org X-Mailman-Version: 3.3.6b1 Precedence: list Subject: [TUHS] Re: Clever code List-Id: The Unix Heritage Society mailing list Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: On Dec 13, 2022, at 8:14 AM, Ralph Corderoy wrote: > > Hi Bakul, > >> Fortune 32:16 was a 5.6Mhz machine and couldn't process 1020KB/sec >> (17 sectors/track of early ST412/ST506 disks) fast enough. As Warner >> said, one dealt with it by formatting the disk so that the logical >> blocks N & N+1 (from the OS PoV) were physically more than 1 sector >> apart. > > Sticking with ST506 hard drives, by the time the 8 MHz ARM2 from Acorn > was reading a 56 MB Rodime, it was the drive which couldn't keep up so > executables were stored compressed on disk so the CPU had something to > do, uncompressing the sector's content, while it waited for the next > sector to arrive. :-) IIRC the slow part was due to running some common apps! Not much buffering allowed on a 256KB machine so by the time the app asks for the next block, on a 1:1 interleave the block would be past the read head and you had to spend an extra revolution to grab it!