Some time ago I worked in the IT department of a company that had a corporate standard of two 27″ FUllHD (either 1920*1080 or 1920*1200) monitors for the desktop. I was pushing to make the standard be one 32″ 4K monitor or the two cheaper monitors. They ended up making one 27″ 4K monitor an option which was still a better option for many users than two FullHD monitors due to having twice the pixels even though it had half the screen area. It was a surprise to me when hardly anyone took up that option.

One man who worked there brought a wide curved monitor from home and ran with one of the FullHD monitors on each side of that. As an employee in the IT department I had concerns about expensive personal equipment being used in the office regarding who’s going to pay the bill if it gets broken. But I was assured that it was his old monitor that he didn’t need after buying a better one for gaming at home and he wouldn’t be too upset if something happened to it.

This isn’t the only time I’ve witnessed such problems of companies paying large salaries for skilled people and providing poor equipment for them to do the work. One previous time I raised a OH&S issue because the outdated monitors were so blurry but the company determined that the monitors wouldn’t cause health problems and spending $150 per employee on better replacements was a waste of money.

Computer hardware tends to become cheaper over time and one thing that has become really cheap recently is portable monitors. Kogan has a 15.6″ FullHD monitor with USB-C and mini-HDMI inputs for $89 [1]. It wouldn’t be difficult for someone to put one of those on each side of the monitor or monitors that their employer provides and put them in a desk drawer at the end of the day to minimise risk. The same Kogan page has a 16″ monitor with 2560*1600 resolution for $189.

Company Ownership

I previously wrote about the potential benefits to companies in not owning all those keyboards, mice, and headsets when they could just give each employee the money and have them buy their own [2]. I don’t think we are at the stage where that can be applied to monitors as the cheapest price for a decent monitor is about $500 which takes it out of the disposable price range that keyboards and mice are in. Also from an IT support perspective there are real support issues with monitors and cables having compatibility issues. But paying small amounts of money to reimburse employees who buy cheap portable monitors to supplement their main monitor is a more reasonable option. For some people that will allow noteworthy improvements in work performance.

Who Will it Help?

I don’t think that adding such portable monitors will directly help the majority of workers. I think that to maximise performance and efficiency we need to chase the long tail of improvements. Big monitors, really big monitors (65″ at a larger distance), multiple monitors, standing desks, and whatever else people want.

There was some research from Microsoft some years ago (back when 27″ was a really big monitor) showing that some tasks had a 50% increase in performance with a larger monitor. Now that 27″ is about the smallest monitor size commonly available the potential for improvement is reduced. Probably most workers now already have monitors that provide the benefits to them that the “big monitors” in Microsoft research provided. But there will always be some portion of the user base who will benefit. If you can get a 50% performance boost for 1% of the users that’s really worth doing. If you can get a 0.5% benefit for 100% of the users that is also worth doing and will theoretically give equal benefits.

Costs of Employees

It is claimed that the total cost of an employee including all overheads of management and providing office facilities etc amounts to twice their base salary. If that is the case then a minimum wage employee in Australia costs $100k per year, someone at the low end of the IT pay scale costs $200k, and someone at the high end of the IT scale is around $400k. It seems clearly worthwhile to spend $1000 in hardware purchases for a $100k employee who declares that it will really help their work, anything which is noticeable to the user is going to be more than a 1% difference in performance.

For someone at the high end of the IT pay scale spending $40,000 on hardware to improve their performance could pay for itself. This is not only due to direct return on investment but because the people who do such work are often in key roles in important projects. If there’s too much work for one person on minimum wage to do then you just hire another person. You can’t hire another senior IT person and have them just do the work, it can take months to get up to speed.

But as management in corporations seems unable to recognise this cheap hardware employees can afford to buy with their own money can bridge the gap.

Job Interviews

In future when interviewing for jobs I’ll ask about the hardware that’s to be used. I won’t say “I’m not interested in this job offer because you don’t respect your employees enough to buy adequate hardware”, but I may make it a condition of working at a company that the hardware on my desk will not be obsolete.

• [1] https://tinyurl.com/26bdng24
• [2] https://etbe.coker.com.au/2023/06/22/cheap-peripherals-work/

$ ./packet_edit_meme 
[*] target /bin/su as uid 1000; entry at file offset 0x4340; shellcode 48 bytes
unshare: Permission denied
[-] page-cache corruption failed

Here is the audit log entry for this failure:

type=AVC msg=audit(1785640621.498:1843): avc:  denied  { create } for  pid=1770 comm="packet_edit_mem" scontext=user_u:user_r:user_t:s0 tcontext=user_u:user_r:user_t:s0 tclass=user_namespace permissive=0

Here’s the result of running it from the unconfined_t domain:

$ ./packet_edit_meme 
[*] target /bin/su as uid 1001; entry at file offset 0x4340; shellcode 48 bytes
[+] su entry overwritten; exec'ing su -> interactive root shell
# id
uid=0(root) gid=0(root) groups=0(root),1001(test2) context=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023
# 

Daniel Baumann wrote a blog post describing how this is fixed for Debian systems without SE Linux.

Bruce Schneier wrote an interesting blog post about corporate liability for AI decisions and the German court ruling about Google’s AI summaries [2].

Cybersecurity News has an interesting article about how Pliny the Liberator succeeded in jailbreaking Anthropic’s latest LLM to give instructions on writing exploits, writing exploitable code (backdoors?), and making meth [3].

Andrew Pam wrote about the number of cars with internal combustion engines in NSW decreasing for the first time since 1910, EVs are taking over [4].

Cory Doctorow wrote an informative blog post about Facebook’s attempts to silence whistleblowers and what a pathetic little loser Zuckerberg is [5].

Scott Santens wrote an insightful article about how to effectively levy taxes in the future when “AI” significantly reduces the number of workers [6].

Ron Garrett wrote an insightful post about birthright citizenship in the US and his status as a US citizen who was not born there [7].

The BBC has an interesting article about the Scottish Violence Reduction Unit and how treating violence as a disease can significantly address the problem [8].

The LA Times has an interesting article about Covid19 causing cancer that had been in remission to return, sparking some new research into the effects of viruses on mammals [9].

CMU has an interesting video about ways to physically modify QR codes and how they could be used in real life [10].

Tim Retout wrote an informative post about the pervasive forms of advertising on the Internet, even on the BBC’s site and how some of it can be blocked [11].

The Intercept Fund is a project to address respiratory illnesses and the long term mostly unnoticed costs they cause to society, we need governments and corporations to get on board with this [12].

The German news site DW has an interesting article about activists registering neo-nazi slang as trademarks to prevent the sale of nazi merchanise which funds racism [13].

The Conversation has an insightful article about how in South Sudan and other war ravaged countries the peace process usually just allocates the spoils of war and therefore encourages more war [14].

• [1] https://tinyurl.com/26cnn3og
• [2] https://tinyurl.com/22fewyml
• [3] https://tinyurl.com/2a5t693d
• [4] https://glasswings.com.au/blog/2026-07/05-185304.html
• [5] https://tinyurl.com/26qzcadm
• [6] https://tinyurl.com/2csg4huw
• [7] https://tinyurl.com/2blnzzxg
• [8] https://tinyurl.com/25v5j7v9
• [9] https://archive.md/Gq2jB
• [10] https://www.youtube.com/watch?v=3ddTIa-AhXE
• [11] https://tinyurl.com/2xt9dgfp
• [12] https://tinyurl.com/2y5f26rj
• [13] https://tinyurl.com/29ok2qsu
• [14] https://tinyurl.com/2yxzsp7s

One of the features of systemd that is most controversial is the option to kill user processes when the user logs out. That initially killed screen/tmux/nohup processes too. In recent Debian releases the default configuration of systemd-logind (the login manager for systemd) is to allow processes to keep running, the configuration file /etc/systemd/logind.conf has an option KillUserProcesses that can be enabled to have user processes killed. If you do that then there are options to only kill processes for certain users and to exclude some users (default to excluding root). If using that option you can apparently use a systemd unit to start screen which prevents it being killed on logout.

This is a very handy feature for some particular user cases. One situation was that I was supporting some people who weren’t very good at computers on a system running KDE and some KDE processes would linger. So the option of logout and login again to deal with an issue of akonadi or some other KDE service misbehaving didn’t work. On that system I enabled the option to kill user processes which reduced the number of problems they had while not requiring rebooting.

It is widely believed that the “linger” feature is required to allow screen/tmux/nohup to work, in Debian (and probably most distributions) that is not the case. It might be that some combinations of configuration requires “linger” to allow screen/tmux to work but I am not interested in trying to discover them. Of all the people I have directly supported for Linux desktop use (which numbers in the hundreds) none of them have had the ability to use screen/tmux and also the cluelessnes that makes me want to automatically kill their processes when the logout.

Controlling Linger

You can enable and disable “linger” for your own account with the following commands if polkit is installed and in a typical configuration:

loginctl enable-linger
loginctl disable-linger

If running as root you can enable and disable it for another user with the following commands:

loginctl enable-linger $ACCOUNT
loginctl disable-linger $ACCOUNT

There doesn’t seem to be any documented way of discovering if an account has linger enabled or for listing accounts that have it, it seems that “ls /var/lib/systemd/linger” is the only option.

Linger on Debian

On a Debian system with close to default settings the processes won’t be killed on logout and the only difference “linger” makes is to start programs in the user’s context BEFORE they login. A friend was recently testing out a bunch of LLM programs on one of my servers and the account he used for that ended up with “linger” enabled, presumably one of the install scripts he ran was written on the assumption that enabling linger was necessary for nohup to work and it did so automatically without being asked.

One benefit I’ve found from this behaviour is on my laptop. I’m currently testing out new SE Linux policy on my laptop and rebooting it a lot. When I enabled linger on my account it caused the laptop to connect to wifi on boot without needing to login which is convenient. I can then ssh to it even when the X11/Wayland login configuration is broken.

I will leave it enabled after finishing these tests. Having background processes like Pipewire and Bluetooth start before I login will presumably make things slightly faster when I do login.

In 2018 I reviewed a Thinkpad X1 Carbon Gen6 that was assigned to me for work [1].

In April last year I wrote about the failings of my Thinkpad Yoga Gen 3 and how I was going back to the Thinkpad X1 Carbon Gen5 [2]. The Gen5 in question has 8G of RAM and a 1920*1080 display compared to 16G and 2560*1440 for the Yoga but runs reliably on battery without crashing. The Yoga in question has been used by relatives who don’t need to do much when on battery and is currently being used by a relative who runs Windows so the occasional crash is something they are used to.

In mid last year I bought a Thinkpad X1 Carbon Gen6 for $350 which has 16G of RAM and a 2560*1440 display. The higher resolution display is a significant benefit and while 8G of RAM is still usable for medium to heavy Linux desktop use it does cause problems sometimes. The new laptop I now have is significantly better than the one I had for work in 2018!

I realised that my previous review of that laptop was incorrect in one aspect, there are two USB-C ports it’s just that one may be covered by a rubber stopper when you get it. When I received this one the Ethernet dongle port was covered by a rubber stopper and the seller was unaware of the possibility of using a dongle and didn’t have such a dongle. It’s not a big deal as I have a collection of USB Ethernet devices but would still be handy to have while not worth the $20 it costs to buy one (a 2.5Gbit USB Ethernet device cost me $16 two years ago).

Laptop Displays

Today I saw a Thinkpad X1 Carbon Gen9 with 3840*2400 display and 16G of RAM for $550 on Facebook marketplace, which is a very tempting deal. 3840*2400 is 2.5* as many pixels as 2560*1440 while 2560*1440 is only 77% more pixels than 1920*1080. So if my eyes were able to properly distinguish pixels that that high DPI then the benefits of getting the 3840*2400 laptop would be greater than going to what I currently have from FullHD. But as a 1440p display in a 14″ form factor is already past the stage where I can see individual pixels the benefits of 4K are more about making curves more rounded which improves readability and allows slightly smaller font sizes but doesn’t give anything like the benefits that going from a FullHD desktop monitor to a 4K desktop monitor.

Also I have different usage patterns for my laptop than for my desktop. I use my laptop for reading blog posts and ebooks for which even FullHD would be fine as the amount of text that can be usefully displayed on screen isn’t that great. I also use my laptop for emergency sysadmin work, ssh to a server to restart a daemon, run ping while changing network hardware, and other things where I don’t have a lot of text on screen.

I also use my laptop for light coding tasks while watching TV. It’s not possible to effectively do complex debugging tasks while watching TV or while using a small screen. But a very large portion of coding time is spent dealing with things like testing builds with different versions of libraries, applying patches to a new upstream release of software, fixing issues related to functions being renamed, testing to see if a new version has really fixed a bug it’s supposed to fix, and other things that don’t require a lot of skill.

I am not claiming that 4K displays aren’t great for laptops. Merely that at the current time it’s not worth $550 of my money.

Future Thinkpads

I like the Thinkpad X1 Carbon line and plan to continue buying them as they get cheap.

The Gen11 is the first one to have a minimum of 16G of RAM, the reason this is important to me is that the ones I buy aren’t the lowest model because I want more than the minimum display resolution. As people who get above the minimum spec in one area tend to get above the minimum in others that means that there will be plenty of Gen11s on the market with 32G of RAM when I’m ready to buy one of that era. Presumably by that time Linux software will have become more bloated and make me want more RAM. Yes soldered RAM has some downsides, but if you want an ultra-light laptop it’s a trade-off you need to deal with. One problem with the Gen11 is that the maximum display resolution is 2880*1800, it’s still a reasonable improvement over what I’ve currently got but not close to the 4K I desire.

The Gen12 has support for 8K display at 60Hz over Thunderbolt which is nice. By the time the Gen12 is in my price range it’s quite likely that I will have a monitor with higher than 5120*2160 resolution (the maximum video out resolution of Gen11 and previous models in the Thinkpad X1 Carbon range) on my desk.

The Gen13 still has 2880*1800 as the maximum resolution but has OLED as an option.

So it looks like a Gen9 or Gen10 may be ideal for me as they are the last ones in the Thinkpad X1 Carbon series to support 4K displays. Another option is the Thinkpad Yoga Gen8 which is of the same era as the Thinkpad X1 Carbon Gen11 but has a 3840*2400 OLED touch screen, I might be able to get one of those cheap with the touch screen damaged.

• [1] https://etbe.coker.com.au/2018/09/11/thinkpad-x1-carbon-gen-6/
• [2] https://etbe.coker.com.au/2025/04/23/last-yoga-gen3/

ECC RAM corrects errors that occur in memory before it gets to the CPU. The most common form of ECC is the Hamming Code [1] which when it has R redundant bits can correct single bit errors and detect double-bit errors in messages with 2^R-R-1 bits of data. For PC use that means if you want to protect 32bits of data you need R=6 and with 64bits you need R=7. The standard for DDR4 and similar RAM is 72 bits of data width on the bus and Hamming codes to correct single bit errors and detect double bit errors for 65bits of data. The computers we use have 64bits of data so that allows an extra bit that could be an extra parity, I don’t know what if anything is done with this extra bit.

RDIMM vs UDIMM

One point of confusion in such things is the difference between Registered memory AKA RDIMMs [2] and regular PC/laptop memory which is often referred to as UDIMMs. The “register” is just a buffer which due to complex issues that aren’t relevant to this post means that DIMMs can be larger and you can have more DIMMs in a system but latency may be slightly worse. It is technically quite possible to create RDIMMs without ECC (64bits wide instead of 72) but I have never seen a system that used such RAM.

I have used more than a few systems with ECC UDIMMs and I recommend avoiding them if convenient as ECC UDIMMs are expensive on the second hand market while ECC RDIMMs can get very cheap. There are servers with ECC RDIMMs that are very unsuitable for home use (such as dual-CPU 1RU servers which are very noisy) so once they are past the 5 year tax write-off period the server chassis gets sent to ewaste and the RAM goes on the second hand market, the glut of RAM without systems to use it forces the price down.

For the systems most commonly seen there are RDIMM systems with ECC and UDIMM systems without ECC.

Chipkill

If every bit in RAM was independent of every other bit then the basic Hamming code would solve most problems. However multiple bits in the same chip may be affected by the same problem, or one chip on the DIMM might entirely fail. With every RDIMM having 18 or 36 DRAM chips there are 2 or 4 bits per chip. On DIMMs with 36 DRAM chips one chip could fail and have the errors reliably detected with a Hamming code. On DIMMs with 18 DRAM chips one failed chip can’t necessarily be detected with Hamming codes. IBM trademarked the term ChipKill for ECC systems which can cope with a single DRAM chip failing [3]. This is referred to as “Advanced ECC” on Dell and HP servers which require an even number of DIMMs. If anyone knows what coding method is used for “ChipKill” type systems then please let me know.

Systems with advanced ECC also often have features like hot-spare for RAM and RAID-1 type functionality which is interesting but not something most people who read my blog will ever want to use.

DDR5

DDR5 has on-die ECC to deal with the increased error incidence from smaller and faster memory [4], this is specified as 8 bits of error correction per 128 bits of data which implies basic Hamming codes.

The on-die ECC is not a replacement for regular ECC, it’s a mitigation for new problems introduced. My experience of memory errors is that the majority of repeatable errors (where a system would get an error with Memtest86+ or an ECC error report repeatedly) were DIMM seating issues, I could unplug and reinsert the DIMM in question and then the same tests would pass. Those errors would not be affected by on-die ECC.

One thing that concerns me is the possibility of on-die ECC interacting with ECC on the motherboard and reducing it’s effectiveness. I haven’t been able to find out enough about how this works to determine if that’s the case. My concern is that an error of 3+ bits that’s corrected with a basic Hamming code might be more likely to create an error condition that “Advanced ECC” can’t fix than the original error.

Currently the best published research on the effectiveness of ECC on RAM errors is the Google paper published in 2009 which is based on DDR and DDR2 RAM [5]. So I don’t expect that we will see published research about even DDR4 ECC any time soon. I presume that Google and the other cloud providers are still doing such research and providing the information to DRAM vendors under NDA so we have to just hope that the DRAM vendors do what’s required to make things work correctly and allow us to buy products based on that research.

DDR5 EC4 vs EC8

DDR5 supports 2*32bit “subchannels” instead of just supporting 64bit words [6]. For DDR5 ECC RAM there are variants EC4 which has 36bits of data per subchannel and EC8 which has 40 bits. EC8 allows Hamming codes on each subchannel indepdendently. I haven’t found a reference on how exactly EC4 works, it could be reading 64bits at a time (not taking advantage of the subchannels) to use Hamming codes or it could have 1 parity bit for each subchannel and just assume that there’s no need to check Hamming codes unless the subchannel parity fails. EC8 allows full Hamming code checks on 32bits of data and presumably ChipKill on 64bits.

It’s widely claimed that all DDR5 RDIMMs are EC8 and all DDR5 ECC UDIMMs are EC4. A quick search on ebay turned up adverts for EC4 and EC8 RDIMMs and links to apparently reliable sites confirming that some of the RDIMMs are EC4. There are reports of EC8 UDIMMs even though I couldn’t find any advertised. This seems to mirror the situation with DDR4 where non-ECC RDIMMs are apparently available somewhere and ECC UDIMMs are something I’ve used a few times but most people have never seen.

I then searched for information on what servers support. The Dell R760 server supports both EC4 and EC8 RDIMMs but you can’t have both in the same system.

The existence of EC4 DIMMs is wrong. They shouldn’t make substandard gear, the manufacturing price difference between 72 and 80 bit wide DIMMs isn’t going to be great and the end result is some systems with inadequate specs and extra difficulty in upgrading systems with more things to check for compatibility.

Why ECC is Needed

Here’s an interesting article about Mozilla’s claim that 15% of Firefox crashes are due to RAM hardware errors [7], this seems to be based on repeatable errors and therefore won’t count errors where a bit flip happens once a day or less.

Some years ago I reported a BTRFS corruption issue on my desktop PC to the BTRFS developers and one of them stated that the corruption in question didn’t match any pattern expected from a BTRFS bug and recommended that I run Memtest86+. The memory test revealed that I was getting about one memory corruption per 5 hours so if I had used Firefox on that system any crashes probably wouldn’t have been regarded as hardware errors with RAM. Those errors caused filesystem corruption and some data loss, if I hadn’t been using BTRFS that could have gone unnoticed for years.

On another occasion I had a VM I was using for testing software I was developing that had some unexpected errors. After working on it for a day I had shared the errors with a mailing list of other developers who also spent some time investigating it. Eventually I began to suspect a hardware problem, I went on site and when I rebooted the system to run Memtest86+ it didn’t even boot as it had errors that stopped the BIOS from even working correctly. It was strange that the system was apparently working correctly and restarting the KVM VM resulted in the same errors happening in the same code and nothing else on the VM apparently having a problem. It turned out that the system had a motherboard problem that made all but one of the DIMM sockets unusable so I ended up sending it to e-waste. That wasted a day of my time and some hours of other people’s time. Presumably on other occasions developer time is wasted due to hardware errors and no-one even realises.

What Society Needs

We need ECC RAM to be more widely used. Ideally we would have some government action to force this given the ongoing cost to society in corrupted data and lost time due to RAM hardware errors. I think that at minimum we need sufficient taxes on non-ECC RAM (and EC4 RAM for DDR5) to make it more expensive when bought new than ECC RAM.

We need to have greater knowledge of the benefits of ECC RAM among computer experts, people need to recommend that computers be purchased with ECC RAM whenever possible and that systems which can’t have ECC RAM (laptops and phones) shouldn’t be used for storing important data.

We need to avoid silly things like having so many variants of RAM to confuse people and make it needlessly difficult to get ECC RAM working.

• [1] https://en.wikipedia.org/wiki/Hamming_code
• [2] https://en.wikipedia.org/wiki/Registered_memory
• [3] https://en.wikipedia.org/wiki/Chipkill
• [4] https://tinyurl.com/2aj7oztw
• [5] https://www.cs.toronto.edu/~bianca/papers/sigmetrics09.pdf
• [6] https://en.wikipedia.org/wiki/DDR5_SDRAM#Subchannels
• [7] https://tinyurl.com/yv4of7hz