Made by Mikal – Page 6

Linkers and Loaders

Post author:mikal
Post published:June 30, 2024
Post category:Book

I've owned this book since it was new in the year 2000, but it has sat on the shelf alone and unloved for at least 20 years. I think I did probably read it back then, but it pre-dates blogged notes about books like this one. However, with my new found interest in assembly language programming for ancient CPU architectures, this seems like the sort of book which I might enjoy again. That said, let's be honest here -- the content is interesting, and this book is still recommended as the best introduction to this topic, which is impressive after a 25 year lifespan -- but Shakespeare this ain't. So I found the book interesting and enjoyed reading it, but wont say much more than that here. I am left with an urge to understand UEFI more. Maybe I should write a bad boot loader? Either way, I've had to add some books on that to the Amazon wishlist now...

Adventures in exploding power supplies

Post author:mikal
Post published:June 22, 2024
Post category:Intel 4004

So this went well... The Intel 4004 microprocessor has slightly weird power supply requirements by modern standards. You see, it needs to be supplied with +5V DC, and -10V DC at the same time to work. (It turns out that this is an artifact of the MCS-4 chipset using PMOS technology not the more modern CMOS. Wikipedia has a good description of the constraints of PMOS, but these include the requirement for a number of supply voltages including a relatively negative voltage.) Now, I found this example circuit in someone else's project: Which to me looked quite a lot like these kits from ebay being fed by an AC power supply: So I ordered a kit off ebay, and then ratted around in the garage to find a random AC power supply. Luckily I found one, because they're not super common compared to the DC power supplies I have huge mounds of. Now of course the kit had no assembly instructions apart from the markings on the PCB, which seemed mostly good enough when coupled with some random googling for polarity information. However, I really needed documentation about the input pins. However, that kit appears to be this aliexpress listing, which…

New Scientist Instant Expert: Human Origins

Post author:mikal
Post published:June 16, 2024
Post category:Book

This book triggered my weak spot. There I was wandering in a book store and it caught my eye. The combination of the promise of instant expertise and and interesting topic area was too much for my already notably poor impulse control with books and a purchase was made. Covering from our distant origins from probably Asia, to stone tool use on African grasslands, to the invention of cooking and farming. The book asserts that 20% of our basal calorie burn is our brain, which drove the adoption to eating meat. While I'm not disputing the number, 20% seems like a lot to me. I wonder if that explains why I find training courses so tiring, my brain is literally consuming extra energy? As an aside, a study by Richard Wrangham mentioned in this book asserts that to live a leisurely western lifestyle using only raw vegetarian food, you'd have to consume 9% of your bodyweight a day. That certainly meshes with the "eat a salad" weight loss advice! So in the end, do I think I am an expert on human evolution? No, not really. The book was an interesting read and I enjoyed it, but perhaps the title…

Colony One Mars

Post author:mikal
Post published:June 12, 2024
Post category:Book

I bought this book because Amazon recommended it to me and it got good reviews. There's a lesson there somewhere. You see, I didn't realise when I bought it that the book is self published, and its a little bit... awkward. Its little things, like clearly needing an editorial pass to make the phrasing flow better, and the fact that the text on the spine of the book is upside down. Literally the first line of the book has a weird justification that looks like Microsoft Word at its worst. Now, I'm not opposed to self published books -- the Silo series (Wool, Shift, and Dust) are self published for example, as is Unix: A History and a Memoir and I liked all of those. That said, first impressions do matter I think. Overall I'd say the sort is interesting, if a bit shallow. The level of plotting is probably in line with what you'd expect from a talented teenager. For example there's not much foreshadowing, characters instead just outright state their nefarious intentions. In the end, I got 85 pages in and realised I just don't care, so I stopped. This book is definitely going in the charity pile.

Project Orion

Post author:mikal
Post published:June 12, 2024
Post category:Book

I was quite excited when this book arrived. It's a bit old (early 2000s) and therefore a bit hard to find, so when Amazon randomly had a "new" copy I snapped it up. This copy is definitely unread, but yet still yellowed with time and the binding is a bit sad. Project Orion is the story of America's attempt to build interstellar space ships powered by small nuclear explosions in the early 1950s. The story is told through the lens of one of the children whose father was a principal researcher on the project and who has now interviewed a lot of the players as well as reading de-classified historical documents. It should be noted that much of the program is still classified -- for example the exact minimum amount of plutonium you need to make a big explosion. The 1950s seem to have been an interesting time for nuclear research, as the technology was seen as both generally hopeful in the sense of finding peaceful uses for this destructive capability, while also being terrifying with the prospect of mutually assured distruction. This project started before NASA existed -- at the time each major branch of the military was competing…

Non-fiction books you really should read

Post author:mikal
Post published:June 5, 2024
Post category:Books

I read a lot of books, mostly fiction. That said, occassionally I come across a non-fiction book that genuinely changes how I think about something. In general I can tell those books a while later, because they're the ones I keep referring people to over and over. So here's a list of the non-fiction books I've read since I started keeping records that I think have changed how I think about the world: The Man Who Broke Capitalism: companies should exist for more than mergely hitting quarterly earnings goals -- they should serve their shareholders, but also their employees and the communities they operate in. In return, long term growth is more likely than with a short sighted approach. The Innovators Dilemma: understanding the behaviour of companies in established markets and how disruption occurs changed how I thought about many of the companies I've worked for. Chip War: the history of the semiconductor industry and its globalization was both interesting and informative about how interconnected our global economy has become. Cult of the Dead Cow: how a group of teenagers looking for fun "hacks" accidentally changed an entire industry's attitude towards responsible disclosure of security vulnerabilities. The Mythical Man-Month: genuinely…

Providing stable EBS volume device files

Post author:mikal
Post published:June 4, 2024
Post category:AWS

So I had a little adventure at work today and I am sure this is going to come up again. Imagine that you have an AWS instance with more than one EBS volume attached. On modern instance types, the EBS volumes appear as NVMe device files, but the naming of the device files is not stable -- it depends on what PCI device is detected by the kernel first etc. It turns out that providing stable names for the device files is a solved problem though! Specifically, CoreOS has udev rules which use a short script to lookup the EC2 EBS device name from the vendor-specific portion of the NVMe id-ctrl data, and provide an appropriate symlink. This saved me a fair bit of mucking around providing stable UUIDs for EBS volume templates, because we can instead just set the device name in the launch template and then have udev enforce that device name on boot. So that's nice. There is of course no real equivalent for OpenStack, as OpenStack generally uses qemu virtual disks not fake NVMe disks. I should think about that some more sometime. For what its worth, GCE uses the device serial number it seems based…

Issues building Kolla images with recent versions of Python requests

Post author:mikal
Post published:June 1, 2024
Post category:OpenStack

If you find yourself having issues building Kolla docker container images with errors like this: INFO:kolla.common.utils:Using engine: docker INFO:kolla.common.utils:Found the container image folder at /home/mikal/src/kerbside-patches/venv-stable/2023.1-patches/share/kolla/docker ERROR:kolla.common.utils:Unable to connect to container engine daemon, exiting INFO:kolla.common.utils:Exception caught: Error while fetching server API version: Not supported URL scheme http+docker It is likely that you're running a recent version of requests which has an unresolved issue. Try downgrading requests manually, like this: $ ...venvpath.../bin/pip install requests==2.31.0 Collecting requests==2.31.0 Downloading requests-2.31.0-py3-none-any.whl (62 kB) ...snip... Successfully installed requests-2.31.0 Thanks for this stack overflow post for the pointer.

The Innovator’s Dilemma

Post author:mikal
Post published:May 29, 2024
Post category:Book

So David at work has been talking about this book quite a lot recently, and that meant I had to read it despite the failure of Debugging to delight me. Interestingly, the book starts by telling the story of the hard disk industry, which aligns well with Chip War's approach of telling the story of the semiconductor industry. Apparently the universe thinks I need to know more tech history! The book asserts that disruptive innovation occurs when incumbent players become too good at serving their current market with improved products or services. While this might seem like the result of rational management, often those products end up over delivering compared to what customers want, and as a result then costing more than customers really want to spend. Disruptors on the other hand often launch with a worse product which doesn't meet the needs of the incumbent's customers, but does address the needs of some previously unserviced market segment. That's great for everyone, until the new player adds sufficient functionality to now be competitive with the incumbent player, but at a lower price point -- that's when life gets sad for the incumbent. An interesting point in the discussion is that the…

Chip War

Post author:mikal
Post published:May 12, 2024
Post category:Book

I think it was Hugh who recommended this book. I'm greatful as it was an excellent read and definitely didn't make me duck over to eBay to buy an Intel 4004 chip set to play with. The book uses the backdrop of our current struggles to retain supremacy in high tech manufacturing versus an ambitious China to tell the story of the semiconductor industry in general. It's a global story of massive proportion, with a huge amount of the global economy now dependent on a product which didn't exist 75 years ago. The story starts just after world war two, with Fairchild Semiconductor and Texas Instruments battling it out to produce integrated circuits from newfangled transistors for the Apollo and Minuteman 2 programs. Importantly, Silicon Valley saw consumer market adoption of semiconductors and cheap efficient Asian manufacturing as key to driving down prices and increasing yield rates. At the same time the Pentagon saw integrated circuits as key to maintaining a technological advantage over their Cold War rivals -- the Soviet Bloc was winning in terms of quantity of armament, so the plan was to win with quality of armament. Effectively, the Pentagon sought to bankrupt the Russians by making…