Born: 1965
Died: 2010+-ish
This is the lowest level of abstraction computer, at which the basic gates and power are described.
At this level, you are basically thinking about the 3D layered structure of a chip, and how to make machines that will allow you to create better, usually smaller, gates.
- https://www.youtube.com/watch?v=CFsn1CUyXWs ASML: TSMC's Critical Supplier, Explained by Asianometry (2021)
- https://www.youtube.com/watch?v=SB8qIO6Ti_M How ASML Won Lithography (& Why Japan Lost) by Asianometry (2021)
- https://www.youtube.com/watch?v=XLNsYecX_2Q ASML: Chip making goes vacuum with EUV (2009) Self promotional video, some good shots of their buildings.
This is the mantra of the semiconductor industry:
- power and area are the main limiting factors of chips, i.e., your budget:
- chip area is ultra expensive because there are sporadic errors in the fabrication process, and each error in any part of the chip can potentially break the entire chip. Although there areThe percentage of working chips is called the yield.In some cases however, e.g. if the error only affects single CPU of a multi-core CPU, then they actually deactivate the broken CPU after testing, and sell the worse CPU cheaper with a clear branding of that: this is called binning https://www.tomshardware.com/uk/reviews/glossary-binning-definition,5892.html
- power is a major semiconductor limit as of 2010's and onwards. If everything turns on at once, the chip would burn. Designs have to account for that.
- performance is the goal.Conceptually, this is basically a set of algorithms that you want your hardware to solve, each one with a respective weight of importance.Serial performance is fundamentally limited by the longest path that electrons have to travel in a given clock cycle.The way to work around it is to create pipelines, splitting up single operations into multiple smaller operations, and storing intermediate results in memories.
They put a lot of expensive equipment together, much of it made by other companies, and they make the entire chip for companies ordering them.
A list of fabs can be seen at: https://en.wikipedia.org/wiki/List_of_semiconductor_fabrication_plants and basically summarizes all the companies that have fabs.
Some nice insights at: Robert Noyce: The Man Behind the Microchip by Leslie Berlin (2006).
One of the companies that has fabs, which buys machines from companies such as ASML and puts them together in so called "silicon fabs" to make the chips
Basically what register transfer level compiles to in order to achieve a real chip implementation.
After this is done, the final step is place and route.
They can be designed by third parties besides the semiconductor fabrication plants. E.g. Arm Ltd. markets its Artisan Standard Cell Libraries as mentioned e.g. at: https://web.archive.org/web/20211007050341/https://developer.arm.com/ip-products/physical-ip/logic This came from a 2004 acquisition: https://www.eetimes.com/arm-to-acquire-artisan-components-for-913-million/, obviously.
The standard cell library is typically composed of a bunch of versions of somewhat simple gates, e.g.:and so on.
- AND with 2 inputs
- AND with 3 inputs
- AND with 4 inputs
- OR with 2 inputs
- OR with 3 inputs
Simulations are then carried out, and the electric properties of those structures are characterized in a standard way as a bunch of tables of numbers that specify things like:Those are then used in power, performance and area estimates.
- how long it takes for electrons to pass through
- how much heat it produces
Open source ones:
- https://www.quora.com/Are-there-good-open-source-standard-cell-libraries-to-learn-IC-synthesis-with-EDA-tools/answer/Ciro-Santilli Are there good open source standard cell libraries to learn IC synthesis with EDA tools?
A set of software programs that compile high level register transfer level languages such as Verilog into something that a fab can actually produce. One is reminded of a compiler toolchain but on a lower level.
The most important steps of that include:
- logic synthesis: mapping the Verilog to a standard cell library
- place and route: mapping the synthesis output into the 2D surface of the chip
Step of electronic design automation that maps the register transfer level input (e.g. Verilog) to a standard cell library.
The output of this step is another Verilog file, but one that exclusively uses interlinked cell library components.
Given a bunch of interlinked standard cell library elements from the logic synthesis step, actually decide where exactly they are going to go on 2D (stacked 2D) integrated circuit surface.
The main ones as of 2020 are:
- Mentor Graphics, which was bought by Siemens in 2017
- Cadence Design Systems
- Synopsys
They apparently even produced a real working small RISC-V chip with the flow, not bad.
It is quite amazing to read through books such as The Supermen: The Story of Seymour Cray by Charles J. Murray (1997), as it makes you notice that earlier CPUs (all before the 70's) were not made with integrated circuits, but rather smaller pieces glued up on PCBs! E.g. the arithmetic logic unit was actually a discrete component at one point.
The reason for this can also be understood quite clearly by reading books such as Robert Noyce: The Man Behind the Microchip by Leslie Berlin (2006). The first integrated circuits were just too small for this. It was initially unimaginable that a CPU would fit in a single chip! Even just having a very small number of components on a chip was already revolutionary and enough to kick-start the industry. Just imagine how much money any level of integration saved in those early days for production, e.g. as opposed to manually soldering point-to-point constructions. Also the reliability, size an weight gains were amazing. In particular for military and spacial applications originally.
Uploaded by the Computer History Museum. There is value in tutorials written by early pioneers of the field, this is pure gold.
Shows:
- photomasks
- silicon ingots and wafer processing
Register transfer level is the abstraction level at which computer chips are mostly designed.
The only two truly relevant RTL languages as of 2020 are: Verilog and VHDL. Everything else compiles to those, because that's all that EDA vendors support.
Compilers for RTL languages such as Verilog and VHDL abstract away the details of the specific semiconductor technology used for those exact same reasons.
The compilers essentially compile the RTL languages into a standard cell library.
Examples of companies that work at this level include:
- Intel. Intel also has semiconductor fabrication plants however.
- Arm which does not have fabs, and is therefore called a "fabless" company.
Basically a synonym for central processing unit nowadays: https://electronics.stackexchange.com/questions/44740/whats-the-difference-between-a-microprocessor-and-a-cpu
- 2020: Traininum in 2020, e.g. https://techcrunch.com/2020/12/01/aws-launches-trainium-its-new-custom-ml-training-chip/
- 2018: AWS Inferentia, mentioned at https://en.wikipedia.org/wiki/Annapurna_Labs
Our definition of fog computing: a system that uses the computational resources of individuals who voluenteer their own devices, in which you give each of the volunteers part of a computational problem that you want to solve.
Folding@home and SETI@home are perfect example of that definition.
Advantages of fog: there is only one, reusing hardware that would be otherwise idle.
Disadvantages:
- in cloud, you can put your datacenter on the location with the cheapest possible power. On fog you can't.
- on fog there is some waste due to network communication.
- you will likely optimize code less well because you might be targeting a wide array of different types of hardware, so more power (and time) wastage. Furthermore, some of the hardware used will not not be optimal for the task, e.g. CPU instead of GPU.
All of this makes Ciro Santilli doubtful if it wouldn't be more efficient for volunteers simply to donate money rather than inefficient power usage.
Bibliography:
- https://greenfoldingathome.com/2018/05/28/is-foldinghome-a-waste-of-electricity/: useless article, does not compare to centralize, asks if folding the proteins is worth the power usage...
Some good insights on the earlier history of the industry at: The Supermen: The Story of Seymour Cray by Charles J. Murray (1997).

In conventional speech of the early 2000's, is basically a synonym for dynamic random-access memory.
DRAM is often shortened to just random-access memory.
The opposite of volatile memory.
What you can do however is to erase the entire thing with vendor support, which most hardware has support for. On hardware encrypted disks, you can even just erase the keys:
TODO does shredding the
Electronic Ink such as that found on Amazon Kindle is the greatest invention ever made by man.
Once E Ink reaches reasonable refresh rates to replace liquid crystal displays, the world will finally be saved.
It would allow Ciro Santilli to spend his entire life in front of a screen rather in the real world without getting tired eyes, and even if it is sunny outside.
Ciro stopped reading non-code non-news a while back though, so the current refresh rates are useless, what a shame.
OMG, this is amazing: https://getfreewrite.com/
PDF table of contents feature requests: https://twitter.com/cirosantilli/status/1459844683925008385
Remarkable 2 is really, really good. Relatively fast refresh + touchscreen is amazing.
No official public feedback forum unfortunately:
PDF table of contents could be better: https://twitter.com/cirosantilli/status/1459844683925008385
Display size: 10.3 inches. Perfect size
The main interface between the central processing unit and software.
A human readable way to write instructions for an instruction set architecture.
One of the topics covered in Ciro Santilli's Linux Kernel Module Cheat.
List of instruction set architecture.
Intel is known to have created customized chips for very large clients.
This is mentioned e.g. at: https://www.theregister.com/2021/03/23/google_to_build_server_socs/
Intel is known to do custom-ish cuts of Xeons for big customers.Those chips are then used only in large scale server deployments of those very large clients. Google is one of them most likely, given their penchant for Google custom hardware.
TODO better sources.
This ISA basically completely dominated the smartphone market of the 2010s and beyond, but it started appearing in other areas as the end of Moore's law made it more economical logical for large companies to start developing their own semiconductor, e.g. Google custom silicon, Amazon custom silicon.
Examples:
- the most powerful supercomputer in the world as of November 2021 was Fugaku by Fujitsu and used an ARM according to TOP500 https://www.top500.org/lists/top500/2021/11/It was later beaten by another x86 supercomputer https://www.top500.org/lists/top500/2022/06/, but the message was clearly heard.
- AWS Graviton
The leading no-royalties options as of 2020.
Leading RISC-V consultants as of 2020, they are basically trying to become the Red Hat of the semiconductor industry.
China has been a major client, since the country is trying to increase its semiconductor industry independence, especially given economic sanctions imposed by the USA.
As a result, SiFive moved its legal headquarters to Switzerland in 2019 to try and overcome some of the sanctions.
Their websites a bit shitty, clearly a non cohesive amalgamation of several different groups.
E.g. you have to create several separate accounts, and different regions have completely different accounts and websites.
The Europe replacement part website for example is clearly made by a third party called https://flex.com/ and has Flex written all over it, and the header of the home page has a slightly broken but very obviously broken CSS. And you can't create an account without a VAT number... and they confirmed by email that they don't sell to non-corporate entities without a VAT number. What a bullshit!
This is Ciro Santilli's favorite laptop brand. He's been on it since the early 2010's after he saw his then-girlfriend-later-wife using it.
Ciro doesn't know how to explain it, but ThinkPads just feel... right. The screen, the keyboard, the lid, the touchpad are all exactly what Ciro likes.
The only problem with ThinkPad is that it is owned by Lenovo which is a Chinese company, and that makes Ciro feel bad. But he likes it too much to quit... what to do?
Ciro is also reassured to see that in every enterprise he's been so far as of 2020, ThinkPads are very dominant. And the same when you see internal videos from other big tech enterprises, all those nerds are running... Ubuntu on ThinkPads! And the ISS.
Those nerds like their ThinkPads so much, that Ciro has seen some acquaintances with crazy old ThinkPad machines, missing keyboard buttons or the like. They just like their machines that much.
ThinkPads are are also designed for repairability, and it is easy to buy replacement parts, and there are OEM part replacement video tutorials: https://www.youtube.com/watch?v=vseFzFFz8lY No visible planned obsolescence here! With the caveat that the official online part stores can be shit as mentioned at Section "Lenovo".
Further more, in 2020 Lenovo is announced full certification for Ubuntu https://www.forbes.com/sites/jasonevangelho/2020/06/03/lenovos-massive-ubuntu-and-red-hat-announcement-levels-up-linux-in-2020/#28a8fd397ae0 which fantastic news!
The only thing Ciro never understood is the trackpoint: https://superuser.com/questions/225059/how-to-get-used-of-trackpoint-on-a-thinkpad Why would you use that with such an amazing touchpad? And vimium.
Model B V 1.1.
SoC: BMC2836
Model B V 1.2.
SoC: BCM2837
Serial from
cat /proc/cpuinfo
: 00000000c77ddb77