etbe - Russell Coker

SAS vs SATA and Recovery

SAS and SATA are electrically compatible to a degree that allows connecting a SATA storage device to a SAS controller. The SAS controller understands the SATA protocol so this works. A SAS device can’t be physically connected to a SATA controller and if you did manage to connect it then it wouldn’t work.

Some SAS RAID controllers don’t permit mixing SAS and SATA devices in the same array, this is a software issue and could be changed. I know that the PERC controllers used by Dell (at least the older versions) do this and it might affect many/most MegaRAID controllers (which is what PERC is).

If you have a hardware RAID array of SAS disks and one fails then you need a spare SAS disk and as the local computer store won’t have any you need some on hand.

The Linux kernel has support for the MegaRAID/PERC superblocks so for at least some of the RAID types supported by MegaRAID/PERC you can just connect the disks to a Linux system and have it work (I’ve only tested on JBOD AKA a single-disk RAID-0). So if you have a server from Dell or IBM or any other company that uses MegaRAID which fails you can probably just put the disks into a non-RAID SAS controller and have them work. As Linux doesn’t care about the difference between SAS and SATA at the RAID level you could then add a SATA disk to an array of SAS disks. If you want to move an array from a dead Dell to a working IBM server or the other way around then you need it to be all SATA or all SAS. You can use a Linux system to mount an array used by Windows or any other OS and then migrate the data to a different array.

If you have an old array of SAS disks and one fails then it might be a reasonable option to just migrate the data to a new array of SATA SSDs. EG if you had 6*600G SAS disks you could move to 2*4TB SATA SSDs and get more storage, much higher performance, less power use, and less noise for a cost of $800 or so (you can spend more to get better performance) and some migration time.

Having a spare SAS controller for data recovery is convenient. Having a spare SAS disk for any RAID-5/RAID-6 is a good thing. Having lots of spare SAS disks probably isn’t useful as migrating to SATA is a better choice. SATA SSDs are bigger and faster than most SAS disks that are in production. I’m sure that someone uses SAS SSDs but I haven’t yet seen them in production, if you have a SAS system and need the performance that SSDs can give then a new server with U.2 (the SAS equivalent of NVMe) is the way to go). SATA hard drives are also the solution for seriously large storage, 16TB SATA hard drives are cheap and work in all the 3.5″ SAS systems.

It’s hard to sell old SAS disks as there isn’t much use for them.

Links December 2023

David Brin wrote an insightful blog post about the latest round of UFO delusion [1]. There aren’t a heap of scientists secretly working on UFOs.

David Brin wrote an informative and insightful blog post about rich doomsday preppers who want to destroy democracy [2].

Cory Doctorow wrote an interesting article about how ChatGPT helps people write letters and how that decreases the value of the letter [3]. What can we do to show that letters mean something? Hand deliver them? Pay someone to hand deliver them? Cory concentrates on legal letters and petitions but this can apply to other things too.

David Brin wrote an informative blog post about billionaires prepping for disaster – and causing the disaster [4].

David Brin wrote an insightful Wired article about ways of dealing with potential rogue AIs [5].

David Brin has an interesting take on government funded science [6].

Bruce Schneier wrote an insightful article about AI Risks which is worth reading [7].

Ximion wrote a great blog post about how tp use AppStream metadata to indicate what type of hardware/environment is required to use an app [8]. This is great for the recent use of Debian on phones and can provide real benefits for more traditional uses (like all those servers that accidentally got LibreOffice etc installed). Also for Convergence it will be good to have the app launcher take note of this, when your phone isn’t connected to a dock there’s no point offering to launch apps that require a full desktop screen.

Russ Albery wrote an interesting summary of the book Going Infinite about the Sam Bankman-Fried FTX fiasco [9]. That summary really makes Sam sound Autistic.

Cory Doctorow wrote an insightful article Microincentives and Enshittification explaining why Google search has to suck [10].

Charles Stross posted the text of a lecture he gave titles “We’re Sorry We Created the Torment Nexus [11] about sci-fi ideas that shouldn’t be implemented.

The Daily WTF has many stories of corporate computer stupidity, but The White Appliphant is one of the most epic [12].

The Verge has an informative article on new laws in the US and the EU to give a “right to repair” and how this explains the sudden change to 7 year support for Pixel phones [13].

Abuse and Free Software

People in positions of power can get away with mistreating other people. For any organisation to operate effectively there have to be mechanisms to address bad behaviour, both to help the organisation to achieve it’s goals and to protect people who work for it.

When an organisation operates in the public interest there is a greater reason to try to prevent bad behaviour as hurting people is not in the public interest.

There are many forms of power, in the free software community a reputation for doing good technical work or work related to supporting software development gives some power and influence. We have seen examples of technical contributions used to excuse mistreatment of other people.

The latest example of using a professional reputation to cover for abuse is Eben Moglen who has done some good legal work in the past while also treating members of the community badly (as documented by Matthew Garrett) [1]. Matthew has also documented how since 2016 Eben has not been doing good work for the free software community [2]. When news comes out about people who did good work while abusing other people they are usually defended with claims such as “we can’t lose the great contributions of this one person so it’s worth losing the contributions of everyone who can’t work with them“, but in such situations it’s very common to discover that they haven’t been doing great work. This might be partly due to abusive people being better at self-promoting than actually doing good work and might be partly due to the fact that people who are afraid to speak out when they are doing good work might suddenly feel ready to go public if the person’s work (defence) is decreasing.

Bradley Kuhn’s article about this situation is worth reading [3].

I don’t have as much knowledge of the people involved in these disputes as Matthew, but I know enough about what is happening to be confident that Matthew’s summary is accurate.

Fat Finger Shell

I’ve been trying out the Fat Finger Shell which is a terminal emulator for Linux on touch screen devices where the keyboard is overlayed with the terminal output. This means that instead of having a tiny keyboard and a tiny terminal output you have the full screen for both. There is a YouTube video showing how the Fat Finger Shell works [1].

Here is a link to the Github page [2], which hasn’t changed much in the last 11 years.

Currently the shell is hard-coded to a 80*24 terminal and a 640*480 screen which doesn’t match any modern hardware. Some parts of this are easy to change but then there’s the comment “I ran once XGetGeometry and I am harcoded (bad) values for x, y, etc..” which is followed by some magic numbers that are not easy to change which are hacked into the source of xvt.

The configuration of this is almost great. It has a plain text file where each line has 4 numbers representing the X and Y coordinates of opposite corners of a rectangle and additional information on what the key is, which is relatively easy to edit. But then it has an image which has to match that, the obvious improvement would be to not have an image but to just display rectangles for each pair of corner coordinates and display the glyph of the character in question inside it.

I think there is a real need for a terminal like this for use on devices like the PinePhonePro, it won’t be to everyone’s taste but the people who like it will really like it. The features that such a shell needs for modern use are being based on Wayland, supporting a variety of screen resolutions and particularly the commonly used ones like 720*1440 and 1920*1080 (with terminal resolution matching the combination of screen resolution and font), and having code derived from a newer terminal emulator. As a final note it would be good for such a terminal to also take input from a regular keyboard so when you plug your Linux phone into a dock you don’t need to close your existing terminal sessions.

There is a Debian RFP/ITP bug for this [3] which I think should be closed due to nothing happening for 11 years and the fact that so much work is required to make this usable.

The current Fat Finger Shell code is a good demonstration of the concept, but I don’t think it makes sense to move on with this code base. One of the many possible ways of addressing this with modern graphics technology might be to have a semi transparent window overlaying the screen and generating virtual keyboard events for whichever window happens to be below it so instead of being limited to one terminal program by the choice of input method have that input work for any terminal that the user may choose as well as any other text based program (email, IM, etc).

Links November 2023

The Long Now has an insightful article about air quality [1].

Every country needs food labelling laws like Mexico has [2]. Also we need to abolish the investor state tribunals, companies should just accept local laws and obey them – or be treated in the same way as pirates on the high seas.

Ian Jackson wrote a good post about conference policies regarding Covid19 [3]. We really need to do more about this, conservatives like to imagine that it’s gone away but people are still getting sick and dying of it.

John Goerzen wrote an informative article about “air gaps” and ways they can be part of a useful and usable security system [4].

This YouTube video has a good introduction to LLMs (Large Languge Models) for machine learning [5].

This eye tracker is interesting technology [6]. The video shows it being used for MS Flight Simulator but it can be used for other things. Unfortunately the price of about $550 Australian puts it out of range of a lot of free software work. I think this would be good for tracking the user FOR THEIR BENEFIT so that notifications won’t be delivered when the user is concentrating.

This ABC article about the risk of a past Covid19 infection exacerbating or accelerating Parkinson’s or Alzheimer’s is a worry [7].

Sam Hartman wrote an insightful blog post about AI safety, consent, and discussions of sex [8].

Links October 2023

The Daily Kos has an interesting article about a new more effective method of desalination [1].

Here is a video of a crazy guy zapping things with 100 car batteries [2]. This is sonmething you should avoid if you want to die of natural causes. Does dying while making a science video count for a Darwin Award?

A Hacker News comment has an interesting explanation of Unix signals [3].

Interesting documentary on the rise of mega corporations [4]. We need to split up Google, Facebook, and Amazon ASAP. Also every phone platform should have competing app stores.

Dave Taht gave an interesting LCA lecture about Internet congestion control [5]. He also referenced a web site about projects to alleviate the buffer bloat problem [6].

This tiny event based sensor is an interesting product [7]. It could lead to some interesting (but possibly invasive) technological developments in phones.

Tara Barnett’s Everything Open lecture Swiss Army GLAM had some interesting ideas for community software development [8]. Having lots of small programs communicating with APIs is an interesting way to get people into development.

Actually Hardcore Overclocking has an interesting youtube video about the differences between x8 and x14 DDR4 DIMMs [9].

Interesting YouTube video from someone who helped the Kurds defend against Turkey about how war tunnels work [10]. He makes a strong case that the Israeli invasion of the Gaza Strip won’t be easy or pleasant.

Hello Kitty

I’ve just discovered a new xterm replacement named Kitty [1]. It boasts about being faster due to threading and using the GPU and it does appear faster on some of my systems but that’s not why I like it.

A trend in terminal programs in recent years has been tabbed operation so you can have multiple sessions in one OS window, this is something I’ve never liked just as I’ve never liked using Screen to switch between sessions when I had the option of just having multiple sessions on screen. The feature that I like most about Kitty is the ability to have a grid based layout of sessions in one OS window. Instead of having 16 OS windows on my workstation or 4 OS windows on a laptop with different entries in the window list and the possibility of them getting messed up if the OS momentarily gets confused about the screen size (a common issue with laptop use) I can just have 1 Kitty window that has all the sessions running.

Kitty has “Kitten” processes that can do various things, one is icat which displays an image file to the terminal and leaves it in the scroll-back buffer. I put the following shell code in one of the scripts called from .bashrc to setup an alias for icat.

if [ "$TERM" == "xterm-kitty" ]; then
  alias icat='kitty +kitten icat'
fi

The kitten interface can be supported by other programs. The version of the mpv video player in Debian/Unstable has a --vo=kitty option which is an interesting feature. However playing a video in a Kitty window that takes up 1/4 of the screen on my laptop takes a bit over 100% of a CPU core for mpv and about 10% to 20% for Kitty which gives a total of about 120% CPU use on my i5-6300U compared to about 20% for mpv using wayland directly. The option to make it talk to Kitty via shared memory doesn’t improve things.

Using this effectively requires installing the kitty-terminfo package on every system you might ssh to. But you can set the term type to xterm-256color when logged in to a system without the kitty terminfo installed. The fact that icat and presumably other advanced terminal functions work over ssh by default is a security concern, but this also works with Konsole and will presumably be added to other terminal emulators so it’s a widespread problem that needs attention.

There is support for desktop notifications in the Kitty terminal encoding [2]. One of the things I’m interested in at the moment is how to best manage notifications on converged systems (phone and desktop) so this is something I’ll have to investigate.

Overall Kitty has some great features and definitely has the potential to improve productivity for some work patterns. There are some security concerns that it raises through closer integration between systems and between programs, but many of them aren’t exclusive to Kitty.

Bluetooth Versions and PineTime

I’ve done some tests with the PineTime [1] on different Android phones. On a Huawei Mate 10 Pro (from 2017 with Bluetooth 4.2) it has very slow transfer speeds for updating the firmware (less than 1KB/s) and unreliable connection to the phone. On a Huawei Nova 7i (from 2020 with Bluetooth 4.2) it has slow transfer speeds (about 2KB/s) and a more reliable connection to the phone. On a Pixel 4 XL (from 2019 with Bluetooth 5.0) it has very fast speeds for updating the firmware and also a reliable link.

Version 5 of the Bluetooth standard [2] was released in 2016 so it’s a little disappointing that the Mate 10 Pro doesn’t support it and very disappointing that the Nova 7i doesn’t support it either. Bluetooth 5 adds higher speeds and longer range for LE (Low Energy) modes which are used for things like smart watches.

It’s extremely disappointing that the PinePhonePro [3] only supports Bluetooth 4.1. It’s a phone released in 2021 that doesn’t even have Bluetooth 4.2 which was released in 2014.

For laptops the Thinkpad X1 Carbon 7th Gen release in 2019 [4] was the first in the X1 Carbon series to have Bluetooth 5. So I will probably be limited in my ability to use my personal laptop or PinePhone for testing Linux software that talks to the PineTime and I’ll have to use a laptop borrowed from work.

Brother MFC-J4440DW Printer

I just had to setup a Brother MFC-J4440DW for a relative. They were replacing an old HP laser printer that mysteriously stopped printing as dark as it should, I don’t know whether the HP printer had worn out or if the HP firmware decided to hobble it to make them buy a new printer. In either case HP is well known for shady behaviour with their printer firmware and should be avoided.

The new Brother printer has problems when using wifi and auto DNS. I don’t know how much of that was due to the printer itself and how much was due to the wifi AP provided by Foxtel. Anyway it works better with Ethernet and a fixed address (the wifi AP didn’t allow me to set a fixed address). I think the main thing was configuring CUPS to connect via the IP address and not use Avahi etc.

One problem I had with printing was that programs like Chrome and LibreOffice would hang for about a minute before printing, that turned out to be due to /etc/cups/lpoptions having the old printer (which had been removed) listed as the default. It would be nice if the web configuration for cups would change that when I set the default printer.

CUPS doesn’t seem to support USB printing. If it is possible to get this printer to print via USB then I welcome a comment describing how to do it.

Scanning only seems to work on Ethernet not on USB, the command for scanning that I ended up with was “scanimage -d escl:http://10.0.0.3:80“. Again I welcome comments from anyone who has had success in scanning via USB. There are probably some Linux users who would find it really inconvenient to setup a network interface specifically for printing. It’s easy for me as I have a pile of spare ethernet cards and a box of cables but some people would have to buy this. Also it’s disappointing that Brother didn’t include an Ethernet cable or a USB cable in the box. But if that makes it cheaper I can deal with that. The resolution for scanning is only 832*1163 and it’s black and white, I think that generally scanning in printers is a bad idea, taking a photo with a phone is a better way of scanning documents.

Generally this printer works well and is cheap at only $299, a price for disposable hardware by today’s standards.

There are Debian packages from Brother for the printer. The scanner package looks like it just configures scanimage, and I’m not sure whether the stock version of CUPS in Debian will do it without the Brother package. One thing I found interesting is that the package mfcj4440dwpdrv has the following shell code in the postinst to label for SE Linux:

if [ "$(which semanage 2> /dev/null)" != '' ];then
semanage fcontext -a -t cupsd_rw_etc_t '/opt/brother/Printers/mfcj4440dw/inf(/.*)?'
semanage fcontext -a -t bin_t          '/opt/brother/Printers/mfcj4440dw/lpd(/.*)?'
semanage fcontext -a -t bin_t          '/opt/brother/Printers/mfcj4440dw/cupswrapper(/.*)?'
if [ "$(which restorecon 2> /dev/null)" != '' ];then
restorecon -R /opt/brother/Printers/mfcj4440dw
fi
fi

This is the first time I’ve seen a Debian package from a hardware vendor with SE Linux specific code. I can’t just add those rules to the Debian policy as that would make the semanage commands fail to add an identical context spec will break the postinst.

In the latest policy I’m uploading to Debian/Unstable (version 2.20231010-1) there are the following 3 lines to deal with this, the first was already there for some time and the other 2 I just added:

/opt/brother/Printers/([^/]+/)?inf(/.*)?        gen_context(system_u:object_r:cupsd_rw_etc_t,s0)
/opt/brother/Printers/[^/]+/lpd(/.*)?   gen_context(system_u:object_r:bin_t,s0)
/opt/brother/Printers/[^/]+/cupswrapper(/.*)?   gen_context(system_u:object_r:bin_t,s0)

The Brother employee(s) who added the SE Linux code to their package are welcome to connect to me on LinkedIn.

More About the PineTime

Since my initial review of the PineTime 10 days ago [1] I’ve used it in more situations. My initial tests were done connecting to a Huawei Nova 7i [2], I am now using it with a Huawei Mate 10 Pro. I’ve also upgraded the PineTime from version 1.11 (from memory) of the Infinitime software that runs on the watch to version 1.13 [3]. To upgrade it I had to download the file pinetime-mcuboot-app-dfu-1.13.0.zip to the Android phone and then use the File Installer option of the GadgetBridge Android app to upload it. The zip file does NOT need to be extracted first, I don’t know if GadgetBridge extracts it before upload or if the PineTime firmware has a copy of unzip, but it just works.

Version 1.13 is purported to take less battery, I haven’t directly verified this as I turned on the new feature of measuring my pulse 24*7 which significantly increases battery use. The end result is that the battery is being used up at about the same rate as before, overall adding a new battery-hungry feature while reducing battery use for other things to compensate is a good thing and strongly suggests that battery use has decreased overall.

I have noticed that now with a different phone and different version of the firmware it doesn’t reconnect as reliably. Sometimes I need to turn bluetooth on the watch off and on before it works (which indicates an issue with the firmware) and sometimes I need to turn bluetooth off and on on the phone which indicates a phone issue. Also I often unlock my phone to find the GadgetBridge notification saying that it’s disconnected and it usually connects fine, but I get the impression it’s often disconnected. Does the Mate 10 Pro have a problem that triggers a bug in the PineTime? Does the 1.13 version of InfiniTime have a problem that triggers a bug in the Mate 10 Pro? Are they both independently buggy? Is the new version of InfiniTime just disconnecting when it’s not doing stuff to save battery and triggering bugs that weren’t obvious before?

I’ve tested the media control which basically works, sometimes it gets out of sync and displays the name of the previous track which is annoying. The PineTime is IP67 rated and there are reports on Reddit of people wearing it in the shower and swimming pool. I wouldn’t recommend those things although it should work OK. It might be an option for controlling music when in the bath or when having a pool party.

When the watch is running normally and displays a new notification it’s not possible to swipe it away. You have to go to the notifications menu afterwards to swipe them which I find annoying. Also the notification of an inbound call remains in the notification list indefinitely while I think a more appropriate action is to have it disappear in an amount of time where it’s already been answered or gone to voicemail. Voicemail timeouts are as low as 15 seconds so having the notification disappear after 1 minute would be reasonable.

I have configured my PineTime to take 2 taps on the screen to wake up. I previously had it set to 1 tap and had problems with accidentally doing something it registered as a tap while in bed and waking me up. Also I found that if I want to turn the screen on when my hands are dirty so I don’t want to touch it with a finger then tapping it on my nose works well. Apparently it is programmed to ignore taps on large areas so I can’t wake it with my elbow.

I’ve setup a PineTime for an elderly relative who is greatly enjoying it. I don’t expect them to flash new firmware or do any other complex things, but they are doing well with using the device. They are considering getting a different band as they don’t like rubber. I’m sure their local jeweler has some leather and metal bands that could fit. There is a design on Thiniverse for a PineTime case [4], this could be used for making an adaptor to fit a PineTime to a greatly different type of band, an instrument console, etc.

Generally I think the PineTime is an OK smart watch for someone who’s not into FOSS for it’s own sake. My relative could have been happy with a slightly cheaper watch, but it’s still significantly cheaper than the Samsung and Apple options so it’s not particularly expensive. A benefit for them is that having the same type of SmartWatch as me they will get better tech support.

etbe – Russell Coker

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SAS vs SATA and Recovery

Links December 2023

Abuse and Free Software

Fat Finger Shell

Links November 2023

Links October 2023

Hello Kitty

Bluetooth Versions and PineTime

Brother MFC-J4440DW Printer

More About the PineTime

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