Microcontroller by Ciro Santilli 40 Updated 2025-07-16
As of 2020's, it is basically a cheap/slow/simple CPU used in embedded system applications.
Pinto bean by Ciro Santilli 40 Updated 2025-07-16
This seems to be the "brown Brazilian bean" that many Brazilians eat every day.
Edit: after buying it, not 100% sure. This one felt smaller than what Ciro had in Brazil, borlotti beans might be closer. Pinto beans are smaller, and creamier, and have softer peel, possibly produced less natural gas.
2021-04: second try.
2021-03: did for first time, started with same procedure as borlotti beans 2021-03. Maybe 1h30 is too much. Outcome was still very good.
Intel is known to have created customized chips for very large clients.
This is mentioned e.g. at: 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.
Free:
Non-free:
  • bovet05 chapter "Memory addressing"
    Reasonable intro to x86 memory addressing. Missing some good and simple examples.
Peter Cordes mentions that some architectures like MIPS leave paging almost completely in the hands of software: a TLB miss runs an OS-supplied function to walk the page tables, and insert the new mapping into the TLB. In such architectures, the OS can use whatever data structure it wants.
After removing it:
  • the black tape used pulled out the paint in parts of the wall, and even worse small bits of plaster on some corners
  • the sticky from the blinds bits also pulled out a bit of plaster
Of course, we already knew that minimal plaster work would be needed from the start, since we have to hammer two small nails into the wall. But that level of damage might have been easily dealt with by a non-professional tenant himself. But the level I had was a bit more than I felt I should handle myself.
Figure 1.
Total Blackout Cassette Roller Blind wall damage.
Source.
Reptile by Ciro Santilli 40 Updated 2025-07-16
This being a class is bullshit because it is not a clade, notably birds are not considered reptiles, but they are clearly in the clade.
Paging is done by the Memory Management Unit (MMU) part of the CPU.
Like many others (e.g. x87 co-processor, APIC), this used to be by separate chip on early days.
It was later integrated into the CPU, but the term MMU still used.
In v4.2, look under arch/x86/:
  • include/asm/pgtable*
  • include/asm/page*
  • mm/pgtable*
  • mm/page*
There seems to be no structs defined to represent the pages, only macros: include/asm/page_types.h is specially interesting. Excerpt:
#define _PAGE_BIT_PRESENT   0   /* is present */
#define _PAGE_BIT_RW        1   /* writeable */
#define _PAGE_BIT_USER      2   /* userspace addressable */
#define _PAGE_BIT_PWT       3   /* page write through */
arch/x86/include/uapi/asm/processor-flags.h defines CR0, and in particular the PG bit position:
#define X86_CR0_PG_BIT      31 /* Paging */
Besides a missing page, a very common source of page faults is copy-on-write (COW).
Page tables have extra flags that allow the OS to mark a page a read-only.
Those page faults only happen when a process tries to write to the page, and not read from it.
When Linux forks a process:
  • instead of copying all the pages, which is unnecessarily costly, it makes the page tables of the two process point to the same physical address.
  • it marks those linear addresses as read-only
  • whenever one of the processes tries to write to a page, the makes a copy of the physical memory, and updates the pages of the two process to point to the two different physical addresses

Pinned article: Introduction to the OurBigBook Project

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