April 2019 - Talk - lists.gtalug.org

string representation is tricky
by D. Hugh Redelmeier 17 Apr '19

17 Apr '19

In some recent context, probably GTALUG-related, that UTF-16 is dumb. That it is the worst of two worlds: that not all characters could be represented as a single 16-bit value, that byte-order issues arise in byte streams of UTF-16, that UTF-16 is wasteful for representing ASCII. Java, Python before 3, Javascript, Microsoft's C and C++, the Jolliete filesystem, the NT File system, and many other things use UTF-8. Dumb. It represents a frozen mistake. Python 3, if I understand correctly, represents strings as arrays of UTF-32 characters. That too is dumb. It is wasteful. The driving justification is that it is thought that indexing an array of characters is an important and frequent operation and it should be O(1) in cost. An array of UTF-8 bytes can be indexed cheaply, but that does not get you to the n'th character. Indexing the character would cost O(n). But it turns out that indexing an array of characters is not a very useful operation. Iterating through the characters of a string is common, but that is a different thing and is cheap to do with UTF-8. I've just read an old blog post that is quite good at showing me even more odd things about UNICODE that I hadn't internalized. <https://manishearth.github.io/blog/2017/01/14/stop-ascribing-meaning-to-uni…> - UNICODE has code points, not characters. - "character" isn't a well defined concept. - a glyph might be made up of a sequence of codepoints combined. - a glyph might have several representations as a sequence of codepoints. - there may not be a canonical form for a glyph. - collating sequence is tough - fixed-width terminals cannot reasonably handle UNICODE - there is a well reasoned argument why indexing by codepoint is not important There's more. I recommend reading it and some of the things it references. Beware: I spent a lot of time following references to references. Example: => <https://eev.ee/blog/2015/09/12/dark-corners-of-unicode/> => <https://en.wikipedia.org/wiki/Ogham> => <https://en.wikipedia.org/wiki/Nimrod> => <https://en.wikipedia.org/wiki/Josephus> Luckilly, the code I write only has to understand ASCII. It has to be able to pass through other code points. UTF-8 is quite good for this.

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"93% of Paint Splatters are Valid Perl Programs"
by D. Hugh Redelmeier 15 Apr '19

15 Apr '19

I found this worth reading. <https://docs.google.com/document/d/1ZGGNMfmfpWB-DzWS3Jr-YLcRNRjhp3FKS6v0KEL…>

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Right to Repair Info Session Mon. Apr. 15
by Karen Lewellen 11 Apr '19

11 Apr '19

Hi folks, Sharing the below from an associate since the effort was discussed here. Karen ---------- Forwarded message ---------- Date: Thu, 11 Apr 2019 18:02:40 -0400 From: Dahne Jobson <jmgmediagroup(a)gmail.com> Subject: Right to Repair Info Session Mon. Apr. 15 [Rescheduled] Thank you for your support and I look forward to seeing you on Monday! *The Right to Repair Info Session is Back On!* Hello CSI Community! MPP Michael Coteau – Don Valley East, is tabling legislation to extend the Consumer Protection Act to include the *Right to Repair Electronics Bill* and will be at *CSI Annex MONDAY APRIL 15, 2:00 pm – 3:00 pm, Mtg Rm #1* to explain his Bill and wants your comments and feedback! ------------------------------ Mr. Coteau’s Right to Repair Bill aims to compel manufacturers to give consumers and repair shops what they need to repair their electronics themselves without voiding warranties, encouraging new product purchases or requiring the consumer exclusive use of the manufacturer’s repair services. Techniques employed by some manufacturers to extend the income cycle of “their” devices include, the gluing in of key components to prevent refurbishment and creating unique screws that require special tools that only the manufacturer has access to. (*Fun Fact: *Once you buy something, it’s *yours*!*)* The Right to Repair affects devices such as cell phones, computers, cars, farm machinery, and household items – washing machines and dishwashers. It also impacts small business, which are at risk of paying exorbitant fees to become registered resellers/technicians or going out of business entirely. The website, the Citizen Truth, features the article, ‘Is Apple Holding Their Consumers Hostage to Unfair Repair Prices? <https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fcitizentru…> *’, *that references a 2018 CBC undercover video, ‘Apple Store hidden camera footage exposes high cost for repairs’ <https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.cbc.ca…>, exposing the extent of consumers’ vulnerability. An Apple customer seeking a remedy for their broken computer was quoted $1200 by the Apple Store rep, but had it repaired at an “unauthorized dealer” for between $75-$150 - the cost of the part, not the labour. *At an even greater cost to the consumer is the environmental impact of the rising amounts of electronic waste entering landfills.* A 2017 United Nations report, ‘Electronic waste poses ‘growing risk’ to environment, human <https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fnews.un.or…> health’, warns that the growing volume of e-waste is an “urgent issue” in an increasing digital-dependent society. The EU and at least 18 U.S. states have adopted Right to Repair, and Mr. Coteau <https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.cbc.ca…>‘s proposed Bill will put Canada on the right side of the debate and the planet. Join the discussion, and learn how you can show Queen’s Park your support when the Right to Repair comes up for debate in mid-April. Space is limited. Please RSVP at: tcmncommunitymediatv(a)gmail.com *CSI Annex MONDAY APRIL 15, 2:00 pm – 3:00 pm Mtg Rm #1* *Presented by: Dahne Jobson, The Toronto Community Media Network* *Copyright © 2019 THE TORONTO COMMUNITY MEDIA NETWORK. All rights reserved.* *Our Email address is:* TCMNCOMMUNITYMEDIATV(a)GMAIL.COM This email was sent to jmgmediagroup(a)gmail.com *why did I get this?* <https://facebook.us19.list-manage.com/about?u=9ecc278638672a4d8e7f58b96&id=…> unsubscribe from this list <https://facebook.us19.list-manage.com/unsubscribe?u=9ecc278638672a4d8e7f58b…> update subscription preferences <https://facebook.us19.list-manage.com/profile?u=9ecc278638672a4d8e7f58b96&i…> THE TORONTO COMMUNITY MEDIA NETWORK · 32 Oakdene Crescent · Toronto, ON M4J4H9 · Canada [image: Email Marketing Powered by Mailchimp] <http://www.mailchimp.com/monkey-rewards/?utm_source=freemium_newsletter&utm…>

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war story: fixing a doc bug can be hard
by D. Hugh Redelmeier 10 Apr '19

10 Apr '19

I'm reading dnf(8) on Fedora 29 and get irked by the layout of the options. --disableexcludes=[all|main|<repoid>], --disableexcludepkgs=[all|main|<repoid>] Here's what "man dnf" shows on a terminal that is 80 columns wide. Ugly. --disableexcludes=[all|main|<repoid>], --disableexcludep‐ kgs=[all|main|<repoid>] For those of you with MUAs that mangle this kind of stuff: the two options don't fit on one line so something broke the line in a terrible place and then filled the whitespace to justify the result. It would be a lot better to just break the line at the whitespace and to not justify the result. The "not justify" part should just fall out of there being no whitespace to stretch. In an attempt to fix this, I tried to figure out how this problem arose. Surely this would be easy -- I was a troff adept forty years ago. And surely troff couldn't have change much because (1) the orginal author, Joe Osssanna, died in 1977 (2) (I think) it is chained down by POSIX standard (3) the language rules made it hard to extend It turns out that the document representation and transformation isn't what I thought it was. It used to be that one wrote man pages in troff, using the "an" macros, optionally with tbl preprocessing for tables. The dnf documentation is in a Python representation called reStructured Text (.rst), not troff. The .rst gets formatted by a thing called sphinx, a complex Python system. Among other things, it produces a formatted manpage that gets shipped inside the dnf RPM. So that seems easy, if odd. But no. That formatting cannot take account of terminal width or characteristics. So the man command, when confronted with one of these files, process it in an intricate way, approximately: gunzip -c /usr/share/man/man8/dnf.8.gz | /usr/bin/preconv -e UTF-8 | /usr/bin/tbl | /usr/bin/nroff -mandoc -Tutf8 | /usr/bin/less -r The most peculiar part of that pipeline preconv. It converts the formatted document back into troff input! In the case of dnf(8), the resulting troff file has a few problems with the paragraph for these option but they don't explain this particular misformatting. The main problem seems to be in the "andoc" macros or in groff (the GNU implementation of *roff). And yes, groff has differences from the troff I knew 40 years ago. Getting this far in the problem has taken a few steps. - download the source for dnf and build the .rpm - attempt to figure out what builds what. The build log isn't as clear as I'd hope. I mistakenly thought it was rst2man but it is sphinx (they do share code). - air my issues on an appropriate mailing list. Contrary to the documentation, you actually have to join the list to post. So far this is the only traffic on the list this month. <https://sourceforge.net/p/docutils/mailman/docutils-users/?viewmonth=201904> Current state: - I think that some things are wrong with the resulting ephemeral nroff document but I don't know what's at fault and it isn't too important to me. I've reported it to the responsible authorities but I'm not sure that they accept that there are problems. - nroff -mandoc is doing something inappropriate with .TP macros but I don't know where the blame lies. It surely requires engaging with another community. I may run out of steam before getting farther.

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Two Things
by Howard Gibson 10 Apr '19

10 Apr '19

I promised to mention the Raspberry Pi Meetup. Power-over-Ethernet: One cable to rule them all, without catching fire! https://www.meetup.com/Raspberry-Pi/events/nwgbwqyzgbpb A second thing has come up that may interest somebody. The York Regional Science and Technology Fair is coming up this Saturday, and they are still looking for judges. From organizer Nathalie Rudner... Dear Howard, Our fair is days away and we are still a few judges short! We would appreciate it if you could please spread the word and/ or consider bringing a friend! A few more judges will help us ensure that every student is judged in a timely manner and that your schedule is not too busy! It also helps us cover for unexpected absences.If you know of someone who would be interested in helping us out, please share the folloing link with them so that they might register. https://secure.youthscience.ca/sfiab/yrstf. I greatly appreciate your help with this,Thank you!Nathalie RudnerYouth Science Canada Regional Coordinator - York Region -- Howard Gibson hgibson(a)eol.ca jhowardgibson(a)gmail.com http://home.eol.ca/~hgibson

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Dell servers for cheap
by Stewart C. Russell 09 Apr '19

09 Apr '19

via Seneca: Please email Lev Piaseckyj at lev(a)masterfile.com to arrange pickup or with questions. == Dell PowerEdge 2950 servers - quantity available: 22 units - some with 2x dual core processors, others with 1x dual core processor - 4GB RAM (8x512MB; only a few have more RAM) - some have PERC RAID controllers - rack mounting rails included - a few fibre channel HBAs may be available - limited quantity of sleds for Serial Attached SCSI (SAS) drives are available - specs: https://www.dell.com/downloads/global/products/pedge/en/2950_specs.pdf Dell PowerEdge 2950 server with ONE dual core processor - $80 each Dell PowerEdge 2950 server with TWO dual core processors - $100 each SAS Hard Drives for PE2950 - 73GB 15k Serial Attached SCSI (SAS) drives - quantity available: 29 units - $20 each wiped (to recover cost of wiping) == Also available: - many older Dell servers: PE2850, PE2750, PE2650, PE1750 with rails - many 19” Dell LCD monitors (models 1908FP, 1907FP, 1905FP) and a few 21" - APC AP7960 Switched Rack PDUs (Power Distribution Units) https://toronto.craigslist.org/tor/ele/d/north-york-apc-ap7960-switched-rac… - McDATA Sphereon 4500 Fabric Switch (fibre channel) https://toronto.craigslist.org/tor/sop/d/north-york-mcdata-sphereon-4500-fa… - 3com SuperStack 4500 50-port ethernet switches https://toronto.craigslist.org/tor/sop/d/north-york-3com-superstack-port/68… - Dell 4210 Server Rack Enclosure, 19” x 42U https://toronto.craigslist.org/tor/sys/d/north-york-dell-4210-server-rack/6… - Dell ML6000 tape library with 2 expansion modules - Dell ML6000 tape library with 1 expansion module - Dell PowerVault 136T tape library - older Cisco ethernet switches, Catalyst 2950, 2960, 3550, 3560 - older 3com 4400 series ethernet switches - older Belkin KVMs - old small Wacom tablets - many computer speakers - many power cables, ethernet cables, power bars Everything would have to be picked up at Masterfile offices, near Eglinton & Wynford Drive. Please email Lev Piaseckyj at lev(a)masterfile.com to arrange pickup or with questions.

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war story: fixing a doc bug can be easy
by D. Hugh Redelmeier 08 Apr '19

08 Apr '19

I was reading some of the documentation of dnf. I also built the dnf package on Fedora 29. In the process, I found (1) a spelling error (2) three error messages pointing at problems with the .rst files It wasn't too hard to figure out what the fixes should be. Since the source is on github, I could just edit the files and make a push request. These three commits were accepted a couple of days later. <https://github.com/rpm-software-management/dnf/commit/9b49b06a6db314a74e904…> <https://github.com/rpm-software-management/dnf/commit/457b5fee28a22af991ce9…> <https://github.com/rpm-software-management/dnf/commit/1b50c40d8cff339d76d09…>

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Help with choosing a WiFi router
by David Mason 02 Apr '19

02 Apr '19

We’ve had a DLINK DIR-628 for quite a while. When it works it has been great, but it drops out several times a day. Sometimes it come back fairly seamlessly, but sometimes you have to turn off the wifi on connected devices and turn it back on again. Power-cycling it always resolves the problem, but it’s annoying. So I guess I’m in the market for a new WiFi router. A little bit of additional range would be great, and if there’s more speed available, so much the better, but as I said, when it’s working, it’s been great. It’s not uncommon for 3 video streams being viewed while I’m ssh’ed into remote systems, or downloading files, or cloning repositories, and it all works fine. Price isn’t a major concern… I’d happily pay for reliability and performance. To the degree it matters, we’re mostly connected from Apple devices (except for the gateway and RAID servers - both of which are Debian - which are wired together). Thanks for any advice! ../Dave

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VM Virtualbox Linux
by R360 Design INC 01 Apr '19

01 Apr '19

Hello everyone, I have a VM virtualbox set up running CentOS Linux. The host OS is Windows 10. I then attempted to set up two-way network communication between the CentOS Guest and my Windows host. Has anyone attempted this and succeeded? I thought it would be straightforward but setting up the NAT adapter, and installing "VM Guest Addition" got me lost. Ultimately, I 'd like to have a Apache server running on my Centos Linux VM, and then access it using a client browser on my host machine. Regards, Jonathan

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