Paolo Amoroso's Journal


ChromeOS Stable 121 rolled out to my ASUS Chromebox 3 and brought with it a one-click option to upgrade Crostini.

Crostini, the Debian based Linux container of chromeOS, was running Bullseye prior to that. ChromeOS 121 popped up a notification with a button offering to upgrade to Debian Bookworm 12.4. After backing up the container I clicked the button in the notification, skipped the backup option as I had already done it, and clicked another button to start the upgrade.

The process was uneventful. ChromeOS displayed a dialog with status messages informing on the progress, then a final message confirming the successful completion.

I checked out the main Linux programs I use and they all seem to be working fine on Bookworm, as well as everighing else. Some programs actually look better as they're built on GUI frameworks that come with an updated and refreshed design.

Upgrading Crostini from Buster to Bullseye a couple of yeas earlier was less smooth. Back then chromeOS didn't provide any user interface for activating the upgrade, so I had to manually run a script. Although the process completed with a few errors, Bullseye has always worked fine on Crostini since then.

#chromeOS #Linux

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I bought a lovely little computer, a Raspberry Pi 400, and two accessories, a 64 GB Samsung Pro Endurance microSD card to hold the file system and a very cheap Full HD webcam for video calls.

Raspberry Pi 400, Samsung Pro Endurance 64 GB microSD card, and Full HD webcam product boxes.

I always wanted a Raspberry computer but assumed the components and cables would take up too much space at my work station.

Recently though I carefully inspected the layout of my desk, the HDMI ports of my HP Pavillon 23cw monitor, and the nearby electrical sockets. Researching the Raspberry Pi 400 convinced me I could set the device on the desk with minimal inconvenience and little space.

This is not a full review but a collection of early impressions and usage notes after working with the device for a week.


Although I have possible uses for the Pi 400, one of the reasons why I got it is not technical: the computer has a delightful form factor.

My daily driver, an ASUS Chromebox 3, is a high end desktop system. But the opportunity of using a different device with a nice form factor is a welcome and refreshing context switch that helps productivity and makes things fun. It's like writers spending time at Starbucks to get some work done instead of sitting and typing at their desk at home.

Another reason for getting the Pi 400 is I always loved Linux. Since switching to chromeOS in 2015 I've been thinking of how to set up a Linux box as a secondary computer within the constraints of my work station. The Pi 400 finally enabled this possibility.

Another major consideration that drew me to the Pi 400 is it's a full, native Linux system specifically designed as a combination of hardware and software to run Linux. Raspberry Pi OS is tightly integrated with the hardware and well supported, which will hopefully spare me the nightmares of Linux updates frequently breaking X-Windows back in the day.

Finally, I wanted a computer for experimenting with various computing technologies, such as ARM on the desktop. And, of course, I wanted an extra computer to play with Medley and other Lisp systems.

The Pi 400 is a member of the Raspberry family at the heart of countless electronics and IoT projects. But, since I'm not a hardware guy, I'll use it mostly as a desktop productivity and software development environment.


I extensively researched the Pi 400 and a key theme of what I learned is performance.

The reviews describe and evaluate performance through a wide range of experiences that doesn't make it easy to figure what to expect. Perhaps because the specs place the device at a spot of the performance spectrum along the transition between realizing responsiveness is suboptimal, and not noticing anything unusual about the way the system reacts.

Therefore, given the affordable price, I accepted the small risk of disappointment and went with the Pi 400.

What I think the reviews don't highlight enough is that, even at the lower end of the performance spectrum, Raspberry absolutely nailed the combination of form factor and price of the Pi 400. It sits at a local maximum in the product space that delivers tremendous value for the money.


The Italian keyboard of my Pi 400, which makes up the entire device, has nearly the same size as the TedGen keyboard of my Chromebox. The keys of the Pi 400 are actually slightly larger than those of the TedGen and support well my typing speed, which is not much.

I feel at ease with the Pi 400 keyboard because I prefer short-travel chicklet units. The plastic feel and feedback aren't an issue for me as, again, the mechanics and build don't interfere with my relatively slow typing.

Although not as smooth and precise as the Logitech mouse of my Chromebox, the Pi 400 one is acceptable despite the occasional lower than average responsiveness.

The Pi 400 instantly recognized the new Full HD webcam as well as my Mixcoder E9 Bluetooth headphones and Brother HL-L2340DW wireless printer. The webcam delivers a smooth feed with Google Meet and good image quality for the price.


I've been using Unix since the early 1990s and Linux since the mid 1990s, so the Raspberry Pi OS desktop and system look mostly familiar.

I personalized the desktop environment to make it look similar to my Chromebox. I set a similar background color, moved the taskbar to the botton like the chromeOS shelf, and set Chromium as the default browser with a matching tab layout.

This is what my Raspberry Pi OS desktop looks like:

Raspberry Pi OS desktop on a Raspberry Pi 400.

Since my daily driver on the desktop is a Chromebox I mostly live in the browser, with a number of tabs often open on Google products. On the Pi 400 Chromium works well enough with Google web apps. But I can't synchronize my extensions and settings with chromeOS as Google removed the functionality from Chromium.

Although most of the programs I need are available, I haven't found an easy to install screencasting tool with Wayland support.


I don't leave the Pi 400 permanently on the desk but set it up on demand.

Whenever I need the device I bring it out, set it on the desk, and connect the cables. One of the cables goes into the HP monitor which the Pi 400 shares with the Chromebox. I can use either computer by switching the monitor input signal with a button.

The only Ethernet wall socket close to the desk is permanently hooked to the Chromebox. The Pi 400 accesses the network over Wi-Fi at up to 70-80 Mbps.

Setup and configuration

To initially set up the Pi 400 I connected it to the Ethernet socket so the required large file downloads and system updates could go faster.

For installing the operating system on the microSD card I originally planned to run the Raspberry Pi Imager tool on my Chromebox under the Debian based Crostini Linux. But, although Raspberry Pi OS is derived from Debian, the only binaries of such an essential tool are available only for Ubuntu. Raspberry does provide instructions for building a package for Debian but network installation on the Pi 400 seemed simpler.

I selected the 64-bit version of Raspberry Pi OS Bookworm desktop and recommended software.

Despite the simplicity of the process, which can complete in less than a quarter of an hour, it took me three reinstallations and a couple of hours because of a subtle Raspberry Pi Imager bug.

I also configured SSH and headless access to the Pi 400 from my Chromebox with the recommended VNC client TigerVNC, the only one that supports Wayland on Raspberry Pi OS Bookworm. But the Pi 400 is just too slow and laggy over VNC with my setup, which makes it viable in a pinch.


The Pi 400 is no gaming rig but delivers enough performance for most ordinary tasks without the feel of constant wait and lag.

This supports well the kinds of tasks I ordinarily carry out such as running a browser with half a dozen tabs, a terminal, and another program or two. I don't consume much media.

The most noticeable manifestation of performance limitations is that programs don't start up instantaneously. For example, Chromium comes up in about 4 seconds. But once programs start, they run with mostly instantaneous responsiveness for common tasks.

YouTube streams consistently smoothly over Wi-Fi at 1080p and full screen, but entering or leaving full screen mode freezes the browser for a few seconds.

I don't mind the overall experience as I'm used to systems with similar architecture like cheap Android tablets and Chromebooks. The Pi 400 actually feels snappier than my Lenovo Yoga N26 Chromebook.

Although not architecturally similar to the Pi 400, the 8-bit single board computers I use for my retrocomputing projects, such as the Z80-MBC2, deliver a comparable feel that's part of the expected experience.

Speaking of retrocomputing, one the reason I got the Pi 400 is to run Medley, other historical Lisp systems, and emulated classic computers at a level of performance closer to the originals. Running Medley on powerful desktop systems or in the cloud is much faster, thus limiting the appreciation of certain design decisions, features, or workflows the systems imposed back in the day.

The more I use the Pi 400, the more the perception of not operating a powerful computer is fading away as I focus on the tasks I use it for.

An example can express and synthesize this perception. As I said earlier, I configured the desktop environment of the Pi 400 to look similar to that of my Chromebox. The Pi 400 often feels so smooth I forget I'm not on the Chromebox.


it's been a week since I unboxed the Pi 400 and I love it.

The product has the perfect combination of features, form factor, and price for my needs. This surprisingly capable little computer is one of the rare lovely products that encourage to use it, be productive, and have fun.

#pi400 #linux

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To code on the Z80-MBC2 and V20-MBC homebrew computers I often transfer text files to and from their CP/M environments.

In one direction I send files from Crostini Linux by dumping them to CP/M, where PIP saves the text to CP/M files. In the opposite direction I run PIP on CP/M to print the files to the screen, where Minicom captures the text and saves it to files on Crostini.

CP/M and Unix have different line break and end of file encodings. In addition, the transfer process may introduce unwanted text. That's why the text files exchanged between the systems need some conversion, to automate which I wrote two short Bash scripts.

The first script, unix2cpm, converts line breaks and the end of file marker in the input to the CP/M encoding and prints the result to stdout. If the optional file name argument isn't supplied the script reads from stdin with a technique I researched. This is the script:

#!/usr/bin/env bash

# Convert line breaks and end of file from Unix to CP/M.
# Usage:
#   unix2cpm [filename]
# Reads from stdin if the optional argument is missing.


cat "$input_file" | unix2dos
echo -e -n '\x1a'

The script calls unix2dos distributed with the dos2unix / unix2dos tools. unix2dos converts line breaks from Unix to MS-DOS, which borrows the encoding from CP/M. unix2cpm needs only to append with echo the ^Z end of file control character.

Once converted, the file is ready to be dumped from Linux to CP/M.

I initiate file transfers in the oppostite direction by executing the Minicom command to capture the terminal output to a file, Ctrl-A L (Capture on/off). Then, at the CP/M prompt, I execute a command like this to print a file to the console:

A>a:pip con:=filename.txt

When printing ends and the A> prompt reappears, I turn off output capture in Minicom to close the capture file. The captured output contains the PIP command in the first line, then the text of the file, and finally the A> prompt in the last line.

To remove the unwanted first and last line I wrote the second script, skipfl (skip first and last). Again, the script reads from stdin if the optional file name isn't supplied and writes to stdout. The code is:

#!/usr/bin/env bash

# Skip the first and last file of the argument file
# Usage:
#   skipfl [filename]
# Reads from stdin if the optional argument is missing.


cat "$input_file" | sed '1d' | sed '$d'

The script calls sed to delete the first and last line with the d command.

No further processing of the captured CP/M output file is necessary as Minicom takes care of inserting the proper line break and end of file encodings.

#z80mbc2 #v20mbc #linux #retrocomputing

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I needed to write some Bash scripts on Linux that read the input from stdin or a file passed as an optional argument, but couldn't figure how.

Googling turned up several designs and examples, such as on StackOverflow, where the script directly processes the input. But I actually wanted the script to assemble a pipeline, feed the input into the beginning, and delegate the processing to the programs and filters in the pipeline.

More googling turned up exactly what I wanted, a reply by the user Daniel buried in a long StackExchange thread.

The trick is to assign to a variable the input stream and feed it into the first program of the pipeline. To demonstrate the technique, the script unlc (unique line count) prints the number of unique lines in the input:

#!/usr/bin/env bash

# unlc - print number of unique lines in the optional input file or stdin
# Usage:
#   unlc [input-file]


cat "$input_file" | sort | uniq | wc -l

The code assigns to input_file the first argument $1 passed to the script, if supplied, or the standard input. Then cat feeds the content of input_file to the rest of the pipeline. The script is invoked by passing a file as an argument or feeding the data into the script's standard input:

$ cat input-file.txt 
$ unlc input-file.txt 
$ cat input-file.txt | unlc

Simple and brilliant.


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My post on why I use a Chromebox was shared on Hacker News and got enough upvotes to receive more than 4,000 views over a day. The feedback in the comments made me realize I didn't explain why I use chromeOS instead of Linux, so here goes.

I did use various Linux distros from the mid 1990s until switching to chromeOS, but I got exasperated with maintenance.

Device driver support was suboptimal. System updates would often break something and throw me to the console, forcing to waste days to troubleshoot and fix whatever broke and restore X. These issues were so frequent I ended up deferring to apply system updates, trading features and fixes for stability.

I had enough with Linux maintenance, realized I was living in Chrome anyway, didn't mind Google, and gave chromeOS a try. Seven years and four chromeOS devices later, I never had a single system update issue. And maintenance simply disappeared.

For years I used also Windows and Mac OS X but I liked Linux — and later chromeOS — much more.

#chromeOS #Linux

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Chrome OS 101 was supposed to prompt to upgrade Crostini, its Linux container subsystem, from Debian Buster to Bullseye. A 9to5Google article on Chrome OS 101 noted:

Linux on Chrome OS now uses Debian 11 (Bullseye) with upgrade prompts available in the Settings app for those on Debian 10 (Buster). You also now get an upgrade log that’s saved in the Downloads folder.

However, when Chrome OS Stable 101.0.4951.59 landed on my ASUS Chromebox 3 with Crostini running Buster, I got no such prompt. A comment by the user Mr. Smith on an About Chromebooks post about upgrading to Bullseye clarified the prompt is hidden behind a flag.

I went through the upgrade process Mr. Smith outlined and it worked, sort of. Here are the steps I took:

  1. enable the flag chrome://flags#crostini-bullseye-upgrade
  2. reboot Chrome OS
  3. accept the prompt to upgrade to Bullseye
  4. open the Terminal app
  5. run the following shell commands:

    $ sudo apt update
    $ sudo apt full-upgrade -y
    $ sudo apt -y autoremove

Sure enough, after rebooting the system I got the upgrade prompt, accepted it, and watched a dialog reporting on the upgrade progress. A dozen minutes later the process ended with the following errors:

Failed to connect to bus: No data available
Failed to connect to bus: No data available
invoke-rc.d: initscript sudo, action "restart" failed.
Failed to connect to bus: No data available
dpkg: error processing package sudo (--configure):
 installed sudo package post-installation script subprocess returned error exit status 1
Errors were encountered while processing:
E: Sub-process /usr/bin/dpkg returned an error code (1)

I'm not sure what triggered the errors. But a few quick checks of Crostini suggested the installed apps work and nothing major seems broken. Therefore, I'm leaving the container upgraded to Bullseye 11.3 as is and monitor it.

#chromeOS #Linux

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Although Linux had been my daily driver for almost two decades, when I switched to Chrome OS I regarded the Crostini Chrome OS Linux container mostly as a curiosity.

Sure, I was eager to have some fun with Linux on my Chromebox. But I already lived fully in the cloud and web apps met all my computing needs. I assumed the main use cases for Crostini were advanced development or DevOps.

To check out Crostini, I installed some astronomical image visualization and processing software for Linux. Next, I used Python preinstalled on Crostini to test the code I was writing with and make sure it ran on a different system.

When I began working on Suite8080, a suite of Intel 8080 Assembly cross-development tools in Python, I needed some CP/M emulators and 8080 tools to test the Python programs I was developing, as well as my Assembly code. Again, installing and running such Linux software on Crostini worked well.

I came to love Crostini, now a key component of my Chrome OS toolset. It lets me run all sorts of niche applications and specialized software for my hobby projects and geeky interests.

#chromeOS #Linux

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My work on Suite8080 is making me rediscover the Unix M4 macro processing language.

Suite8080, a suite of Intel 8080 Assembly cross-development tools I'm writing in Python, includes also an assembler. I designed the latter to optionally read from the standard input, a feature that gives for free macro processing via a separate tool like m4. I can feed macro Assembly source to m4 and pipe the expanded output into the assembler.

The M4 language is a good choice thanks to its power and ubiquity on POSIX systems.

However, m4 is an obscure tool with a learning curve made steep by the unintuitive quoting and expansion rules. There are few resources and no books or tutorials. The very few code samples are abstract, short, and formatted with little or no whitespace and indentation, which doesn't help readability.

After extensive online research, I put together a list of the best learning and reference resources:

#Linux #development

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