Computing setup, software focused

Windows

My company gives software/firmware developers a very capable Windows laptop.  It's got 32 cores, 64 GB of memory, and a 500 GB SSD to which I was able to add another 2 TB SSD.  There are a couple downsides to this machine -- it's kind of heavy and the corporate IT team has this laptop very locked down.  All software installed on it must be on the approved software list which I understand.  It makes it harder to use my corporate laptop as a good development environment though.  I compensate by using Linux machines for the actual development work and relegating the Windows machine to acting as a terminal plus using it for web browsing and corporate communications tasks such as email, Teams, and Slack.  I was able to install VMware which allows me to use the laptop to run Ubuntu Linux VMs which are used for occasional software builds and to host some FPGA development tools to program the firmware I develop onto the embedded hardware it targets.

• Vim - I've been using Vi/Vim as my editor of choice since I took a job which gave me a Sun workstation on my desk.  I've got friends who love various editors such as Emacs, Visual Studio, Notepad+, Atom, and a few others.  I've occasionally experimented with other editors but it's really hard to overcome the muscle memory which comes from using Vi for 35 years.  The benefit is I'm still using a few macros I created that long ago.  I prefer GVim, the GUI version of Vim for its ability to resize windows.
• Putty - I've got Putty profiles for all the Linux machines which I connect to regularly.  Each includes X11 forwarding which gives me the ability to launch X11 apps on any of the Linux hosts I access.  I know that Wayland is more modern but most of the Linux machines I'm accessing run old enough versions of Linux to make Wayland too much trouble to try to use.  Putty supports both SCP and serial connections, making it a handy way to connect to serial console ports.
• WinScp -  This is a great little network file transfer program which supports the SFTP and SCP protocols.  I often use one Linux host to build my software and another to install it so being able to easily transfer files is a necessity.
• VcXsrv -  Since so many of the tools I use require an X11 connection, I need to run a X11 server on Windows.  I actually petitioned our IT group to add this to the approved software list.  It can be a little buggy at times but getting free software approved is always much easier than asking for commercial software be added to the budget.
• TeraTerm -  Believe it or not, sometimes I need to transfer files to an embedded machine which only offers a serial connection.  TeraTerm supports ZMODEM transfers which makes exchanging binary files much easier in that case.
• Kdiff3 -  Capable free GUI file/directory comparison tool and one of the few allowed on my work laptop.
• Microsoft Outlook - Outlook seems to work adequately for basic email and scheduling needs.  It has a terrible search feature which makes it difficult for me to find past emails I need to reference.
• Microsoft Teams - I have never cared for Teams but it's a necessity to allow me to join meetings while working from home.
• Slack - Most of the time this is okay but it's very quirky.  It's a necessity to allow easy connections to people while I'm working from home. 
• Google Chrome - It's the browser chosen by our corporate IT team.  I guess it's a necessity since it's captured the majority of the browser market but I must admit that I've never really cared for its UI. 
• Windows Calculator -  Having a calculator capable of hexadecimal and binary operation is a necessity at times.

 Linux

All of the embedded devices I work with run some version of Linux.  Some actually have multiple copies running on different CPUs.

• Vim - Vim comes preinstalled on all the Linux machines I need to access.  I do often still install Gvim to make it easier to edit files over an X11 connection.
• Putty - I manually install Putty on Linux machines.  It makes it easy to connect to devices on the Linux machine which use a serial port.  It's also handy to do that via an X11 connection.
• GNU Screen - Screen makes it very easy to maintain a persistent connection to a machine which is necessary as some of the firmware builds take over an hour and network hiccups used to kill the build before it was done.  Screen allows me to reconnect after the network issue and see the build continuing as if no interruption had occurred.
• Exuberant Ctags - I've been using ctags to make navigation through unfamiliar code easier for 30+ years now.
• Ack - Ack allows me to do a recursive search for files which contain some string and to limit that search to source files or some other category such as Bitbake files.  I use the ack executable which is implemented as a single perl module which makes it trivially easy to install on Linux machines.  I know there are faster source search tools available but this one is easy to use and works well for me.
• Kdiff3 -  Capable free GUI file/directory comparison tool.
• xxd -  Sometimes I need to examine binary files and this tool is readily available on Linux machines.  It can also help transfer binary files in a pinch by converting a file to its hexadecimal ASCII equivalent, transferring it, and using xxd to convert it back to binary.
• bash - I rely on the bash shell along with awk, sed, grep, find, and other standard GNU Linux tools for the vast majority of my scripting and interactive use needs.  I rely heavily upon bash scripts to help automate much of my development process.

Apps for both Mac & iOS

Here are the apps I run on both the Mac and iOS.

• Music - Sometimes I like to have background music playing to help mask out distracting sounds while I'm working from home.  I have a few playlists which work well for this purpose.  I buy most of my music in MP3 form from Amazon or Bandcamp and import the MP3 files into the Music app.
• Apple Mail -  It's free on Apple devices and does a reasonably good job of keeping my mail accounts in sync between my Mac and my phone.
• Apple Numbers -  Even though this is a spreadsheet, it can also function as a lightweight database app.  I use it to keep track of audio books and e-books I own and which I've read.  I have quite a few of these lightweight databases.  I used to use a great database app called Bento made by FileMaker which had versions for Mac and iOS.  It was discontinued in 2013 and I haven't found a replacement I like better than Numbers although I do occasional search still. 
• Google Calendar - I like it because it seems to be the most flexible in scheduling recurring events.  For example, you can choose the 3rd Saturday of each month or the 21st day of each month.
• Microsoft To Do -  A reasonably good cross platform to do app.

Mac 

My old Intel Mac Mini is getting long in the tooth but still manages to support some of my work and all of my personal computing needs.  Here are some of the apps I run on it.

• ChronoSync -  I've been using ChronoSync for backups for quite a while now and I've very happy with it.
• Little Snitch - I insist on running a top notch firewall program and Little Snitch fills the bill nicely.
• GnuCash - Since I pay most bills electronically, GnuCash lets me keep track of my checking account easily.  I really like its ability to change the sorting from ascending to descending dates since that makes it much easier to compare with my bank's statements.
• Waterfox browser -  I've always liked the Firefox browser for how easily its UI can be customized and for the rich set up plugins which allow safer browsing.  Firefox lost me as a user when they started on their quest to shove AI in every aspect of the browser.  Waterfox is a reasonable fork of Firefox which does not include the unwanted AI features.  I use this for all my general purpose browsing.  I also use the Chrome, Safari, and Vivaldi browsers each for a special purpose.  It limits having to worry about whether cookies from financial or social media accounts are being seen by other websites.
• Vim - The command line version of Vim comes preinstalled on Mac machines.  I still install MacVim to make it easier to edit files and to be able resize windows.

iOS

I use the cheapest iPhone available whenever I need to replace my phone as my personal device.  I've got iOS software I depend upon to make life easier.

• iTunes Remote - This allows me to easily select the playlist from the Mac's Music app.  I used to also use it for pausing music when I had an incoming call but now I rely upon an Anavi Macropad 10 for that purpose which allows me to pause songs without fumbling to bring up an app on my phone.
• PCalc -  Having a calculator capable of hexadecimal and binary operation is a necessity at times and I'm not always near my Windows laptop.
• Overcast - This is my favorite podcast app.  It has the best UI of any iOS app I can think of.
• Audible - Listening to audio books keeps me sane when commuting to work or in warmer weather when I'm doing 3-4 hours of yard work. 
• Libby - App which makes it easy to borrow library books.  Mostly e-books but they also have audiobooks.
• Hoopla -  App which makes it easy to borrow library books.  This seems to have more audiobooks and graphic novels than Libby does.  They also let you borrow and stream digital movies and tv content.
• Two factor authentication apps -  I enable two factor authentication for any website which supports it and apps such as Authy, Google Authenticator, and others make that possible.

Computing setup, hardware focused

Since I work from home the majority of the time and my job involves writing software and firmware for multiple small embedded ARM based devices, my computing setup tends to be a bit more complicated than normal.  I'm also cheap so I've gotten almost everything on sale.

 

The picture above shows some of the equipment at home which makes it easier for me to switch between the many devices I need to use both for work and my personal computing needs.  The red surface everything rests upon is a grounded anti-static mat which is a necessity as I often need to use bare circuit boards for easy access to JTAG connectors.

• Philips 4k monitor.  I often have ssh sessions with anywhere between 2 and 5 Linux systems simultaneously.  That many terminal windows take up a lot of screen space so the fact that a 4k monitor has 4 times as many pixels as the HD monitor I'm stuck using at the office has made working so much easier.  I got this at a good price thanks to a Black Friday sale 3 years ago.
• IOGear KVM switch.  I usually switch between my work laptop, my Mac Mini which is mostly for home use, and a Raspberry Pi 5.  Since this is a 4 port KVM switch, that leaves an extra set of cables to connect to other devices as needed.  I had a cheaper KVM but the move to a 4k monitor forced me to upgrade to one which supported the higher resolution.
• Technical Pro rack mount power supply.  This allows me to easily power on or off any individual device in my setup as needed.
• Raspberry Pi 5.  This is a great development device as there are much better free development tools available for Linux than there are for Mac or Windows.  That provides me with a lot of flexibility in my development and debugging tasks.  It's my favorite computer to work with.
• Anavi Macropad 10.  This device comes with CircuitPython installed which makes it very easy to configure the key codes it can to send to my Mac.  I like this one because it's also got a rotary encoder (which can be used to easily change the volume) with a button on top to pause the music.  I often use my Mac Mini to play background music while I'm working.  Being able to pause music playback, skip to the next song in the playlist, rewind to the previous song, or adjust the volume on the Mac while my keyboard and monitor are switched to my work laptop via the KVM is very handy.  The situation which this keypad helps with most is when I get a call from someone at work and need to quickly pause the music in order to take the call.
• Canon PIXMA G6020 All-in-One Megatank Printer - It's affordable, reasonably fast at printing, doesn't use proprietary ink cartridges, and has copying and scanning capabilities as well.  We've had it a year and are still on the original ink bottles supplied with the printer.  I think we've been through about 6 reams of paper during that time, most of it double-sided.

 

The picture above is an EDID (Extended Display Identification Data) HDMI adapter.  It causes the computer which it's plugged into to continue thinking that the 4k monitor is still plugged into the computer when it's actually switched to another computer via the KVM switch.  The EDID HDMI adapter shown above is connected to my work laptop.  I've got another one plugged into my Mac Mini.  This prevents the windows on whichever machine from being rearranged when the monitor configuration changes via the KVM switch.  More expensive KVM switches sometimes include this capability without requiring an external adapter like this.

 

 

Things which make C/C++ source code easier to understand

I end up reading a lot of C/C++ source code from various sources in my role as an embedded firmware engineer.  There are a few rules I try to follow to make my code easier for others to decipher.

• Include explanations for any acronyms you use in function or variable names and even in comments.  Don't assume that everyone has the same background as you do.
• Don't ever use magic numbers.  When I'm looking for all code which writes or reads a bit within a register, I don't want to have to try to grep for every hex value which includes that bit.  Just define it with a mnemonic name and use the "or" function to define a set of bitmasks required.  Think of the poor sod who gets stuck maintaining your code.
• Start your functions with an open brace starting in column 1 after the function name/parameters.  End functions with a close brace in column 1 for the same reason.  It makes it easier to search for function names within a source file.
• Emulate whatever indentation style you found in the code if you inherited it from someone else.  It's irritating to have a mix of tab and space characters with no hint of what tab stops the author used.  

Whiteboard coding during interviews

I recently responded to a writer I follow on Mastodon and Bluesky who was looking for input for an article she was planning to write about interviews for embedded systems positions.  Since I enjoy her writing and I have loads of experience with embedded systems, I responded to her request.

The act of recalling various interview questions I had been asked or had posed to others made me remember some questions which I disliked intensely.  The type of question I dislike most is being asked to write code on a whiteboard to solve some problem.  I generally enjoy coding and the problems are often interesting but coding on a whiteboard is so different from writing code on computer using a good editor that I've grown to hate it.  I'd almost rather go back to the bad old days of using a keypunch to generate punched cards as source for my program.  When programming I like to start with an outline of the program and fill it in as ideas occur to me which is nearly impossible when stuck with a more linear coding environment such as whiteboard or a sheet of paper.

I've had two memorable experiences responding to requests to code on a whiteboard.  The first was the most absurd question I believe I have ever been asked in a job interview.  Apparently the company I was interviewing with had guidelines for technical interviews and the engineer asking the questions was hellbent on sticking to these guidelines.  He asked me to write an assembly language program for him.  I asked which assembly languages he was familiar with since I was comfortable with about 5 at the time.  Once I discovered that we had no assemblers in common, I pointed out that it made little sense for me to write a program in a language he wasn't familiar with but he insisted on me completing this task so he could check it off on his interview form.  In addition to it being ridiculous to write a program which cannot be evaluated, it's also frustrating trying to write a meaningful assembly language program on the tiny whiteboards available in cubicles since assembly programs tend to be much longer than those written in higher level languages.  Apparently I passed muster as I ended up getting the job.

The second whiteboard coding experience which came to mind ended far more positively.  I was asked to solve a problem in C but ended up needing to keep adding lines which is no problem on a computer but presents a huge obstacle when stuck using a whiteboard and marker.  I managed to come up with an incomplete and messy solution before they called time on me.  Once I got home from the interview, I was still bothered by my performance.  I was able to quickly code up the solution on my computer at home and emailed a working program to the VP of Engineering I had been interviewing with at the time.  He was so impressed that I had followed through with solving the problem that I was offered the job and ended up staying at that company for 9.5 years.  I still hated the initial request for whiteboard coding but was pleased that it resulted in me getting the job.

I'm hoping that the days of being asked to code on whiteboards are relegated to the past.  To tell the truth, since I'm at my last job before retirement. it won't have a huge impact on my life either way but I hate the thought of others being subjected to this absurd practice.

The benefits of a varied technical background

This week I helped a colleague solve a strange problem which he had encountered.  He was modifying some application level code which needed to read from and write to a device driver I had created to control two LEDs on our device.  Previously the application code had only written to the driver but the decision was made to control the two LEDs independently which required reading the old state from the driver prior to updating the LED state.  Fortunately I had included the ability to read the LED status since it improved my ability to debug the device driver.

The problem was caused by the need to interleave reads and writes to the device driver which under Linux gets treated as a file.  Unbeknownst to my colleague, any read or write to a file stream affects the file pointer which keeps track of the location within the file which will be accessed next.  A simple device driver has no need of the file pointer concept but since Linux treats devices as files, the standard library code which enables accesses to devices and files keeps track of the supposed file pointer even if it doesn't need to do so.  In a standard file access, I should have been able to do a fseek (file seek) to the current position between the read and write calls to fix this issue.  Unfortunately, since my device driver is very bare bones, I suspect there was extra call within the device driver needed to handle fseek calls.  I used a brute force fix of closing the device driver and re-opening it within the application code.

Somehow this makes me think of the common wisdom from early in my career which suggested one shouldn't change jobs too often lest one be labeled a "job hopper".  It turns out that job hopping has given me a very diverse background which has improved my chances of finding jobs.  Changing jobs more frequently has helped me escape from jobs where the work was boring or which placed me under managers which were difficult to deal with.

More machine language fun

When I first starting working as a Senior System Analyst at GEISCO (GE Information Systems) in the mid-1980s, they had us logging into mini and mainframe computers via terminals.  Several of the commands we had to use needed elevated privileges which required us to enter a password of the day.  In order to get this special password, they gave us a small script which retrieved this password and most people put a call to this script as part of their network login to automatically show the password of the day.  Being a curious sort, I wanted to know how the script to display the password worked.  Most people found it cryptic since it consisted of several groups of 12 digit numbers and none of the digits were larger than 7.  I knew this likely meant that these digits were octal numbers which require 3 bits each to represent.  Couple that with the fact that the groupings of numbers were 12 digits long told me that they represented 36 bit words.  Since I knew GE made heavy use of Honeywell mainframe computers at the time, I concluded that the script was some type of interpreted machine language program.  So I dug out my old Honeywell assembly language documentation and discovered that the script was a simple little program to issue a system call (MME - Master Mode Entry) and then print out the results.  To test my theory further, I modified the program to shift the characters of the master password so they would print out backwards.  It basically served to entertain me each time I logged in.  It's amazing the little challenges which I find amusing, huh?

While I was working at GE, a project was launched to upgrade the storage device on the CC (Central Concentrator) network node.  One of the tasks performed by the CC was to load software on the other, smaller network nodes and its original 2 MB device was deemed too small to handle network expansion.  Believe it or not, that 2 MB storage device was a magnetic drum from Vermont Research.  I had signed up for this project because the replacement storage device was originally specified as a 10 MB hard drive similar to those used on higher end PCs of that time.  I was anxious to get experience on these disk devices which were cutting edge technology at the time and writing a device driver from scratch sounded like fun.  Somehow Vermont Research found out about the project and submitted a lower bid for an upgrade to a 10 MB drum device.  So my dreams of writing a device driver became the much less interesting task of updating the old device driver to extend the addressing to accommodate the extra storage.  The only challenging part of the project was that the diagnostic program also needed to be updated and somehow the source code for the diagnostic had been lost.  So I was forced to read the punched card deck into the mainframe in order to print out the binary data the deck contained so I could disassemble it.  Then I had to figure out how to write a patch for the diagnostic program.  And finally, I had to figure out how to get the mainframe's card punch to reproduce the same punch card format used by the diagnostic.  For a few days the computer operators for the mainframe got used to me making multiple daily attempts to convert the binary file containing my patches into a format which could be punched in the same format as the diagnostic deck.  They told me that they hadn't seen anyone use the card punch in many years.  Each attempt required me to tweak my program to convert the diagnostic's binary data into a slightly different format.  It wasn't as much fun as I had hoped for but it did prove pretty challenging.

The joys of machine language programming

When I started my career as a field engineer for Honeywell mainframe computers in the late 1970s, I worked a lot of swing and midnight shifts.  While day shift was always pretty busy, the night shifts were often boring.  To entertain myself, I read the CPU manuals with the goal of being able to modify the diagnostic programs used to test the computers.  Occasionally it proved handy to load one of the diagnostics and then to patch them in memory to loop through operations which were failing.  This allowed using an oscilloscope to trace signals of interest though the 80 wire-wrap boards which made up the CPU.

Eventually writing these machine language programs became my favorite pastime on slow nights.  Part of the draw was the maintenance panel switches which made it easy to read and write memory locations.  There was a definite thrill to getting a program working and watching its progress via the flashing lights on the maintenance panel.

For those who aren't familiar with low level programming, machine language programming involves directly entering the binary encoded instructions into memory locations for later execution.  More people are familiar with assembly language programming which replaced the binary programming with mnemonic names for the instructions and any modifiers.  For example, a Honeywell mainframe had an instruction called LDA which loaded the A (or accumulator) register with some value.  In machine language programming, that LDA instruction had the opcode of octal 235.  Older mainframes often used octal encoding instead of the hexadecimal encoding which is more often used today.  The other convenience offered by using assembly language over machine language is that the assembler would calculate the addresses automatically rather than forcing you to manually calculate the address offsets by hand which was painful.

My second job was as a field engineer for DEC PDP-11 minicomputers.  These smaller machines were so much less complex than the mainframes that fixing the hardware wasn't much of a challenge.  The saving grace was the PDP-11 instruction set was simple enough to allow me to quickly come up to speed on its machine language.  When I was in Boston for training, I wrote a machine language program to determine which terminal connected to the PDP-11 had had data entered on its keyboard.  Apparently the way I approached programming was different than most people's because the instructors had trouble figuring out how my program worked.

Believe it or not, the ability to decipher machine language is still useful when I have to use gdb to debug a program.