Autosave: 2025-01-16 07:08:09

neuron/7f1b1cb6-21bf-4030-bc1f-2652dc5970ea/AWS_SQS.md

@@ -48,7 +48,7 @@ to the dead letter queue (DLQ) and remove it from the main queue.
 ![SQS deadletter example](static/SQS-deadletter.png)
 
 If the DLQ reaches a certain threshold this can trigger additional handling such
-as raising an Alert in [CloudWatch](./AWS_CloudWatch.md) or other monitoring
+as raising an Alert in [CloudWatch](AWS_CloudWatch.md) or other monitoring
 tool.
 
 Note that a DLQ is not a distinct entity within the SDK, it is just another SQS

neuron/7f1b1cb6-21bf-4030-bc1f-2652dc5970ea/Boot_process.md

@@ -65,7 +65,7 @@ The de facto standard boot loader for Linux is GRUB: Grand Unified Boot Loader.
 
 You see the GRUB default menu when you first start a Linux machine. It will
 offer you various options for loading your installed OS or other OSs. GRUB is a
-[filesystem](./Filesystems.md) like the main disk. If you press `e` in this
+[filesystem](Filesystems.md) like the main disk. If you press `e` in this
 screen you can view and edit specific boot parameters. Pressing `c` gives you
 access to the GRUB command line interface. This allows you to interact with GRUB
 in the same way as you would with any other filesystem, allowing for advanced
@@ -88,7 +88,7 @@ configuration.
 
 ## Boot diagnostics
 
-Linux keeps a log of the boot process as part of the [journal](./journald.md)
+Linux keeps a log of the boot process as part of the [journal](journald.md)
 log of everything that happens on disk. We can use the command `journalct -k` to
 view the diagnostics generated during the boot. Here is a selection:
 

neuron/7f1b1cb6-21bf-4030-bc1f-2652dc5970ea/DRAM_and_SRAM_memory.md

@@ -5,7 +5,7 @@ created: Friday, July 12, 2024
 
 # DRAM and SRAM memory
 
-There are two types of RAM memory: [SRAM and DRAM](./DRAM_and_SRAM_memory.md).
+There are two types of RAM memory: [SRAM and DRAM](DRAM_and_SRAM_memory.md).
 
 ### DRAM
 

neuron/7f1b1cb6-21bf-4030-bc1f-2652dc5970ea/Dates_in_Python.md

@@ -91,7 +91,7 @@ formatted_datetime = some_datetime.strftime('%Y-%m-%d %H:%M:%S')
 print("Formatted datetime:", formatted_datetime)
 ```
 
-Express a [unix timestamp](./Time_and_computers.md) as DD-MM-YYYY:
+Express a [unix timestamp](Time_and_computers.md) as DD-MM-YYYY:
 
 ```py
 def convert_timestamp(timestamp):

neuron/7f1b1cb6-21bf-4030-bc1f-2652dc5970ea/Internet_Layer_of_Internet_Protocol.md

@@ -18,7 +18,7 @@ The Internet Layer utilises the **Internet Protocol** to determine how devices
 will be publicly identified to devices on other networks and how different
 devices on the same local network will be distinguished from outside of this
 network. This is achieved through
-[Internet Protocol (IP) addresses](./IP_addresses.md).
+[Internet Protocol (IP) addresses](IP_addresses.md).
 
 ## Packets
 

neuron/7f1b1cb6-21bf-4030-bc1f-2652dc5970ea/Link_Layer_of_Internet_Protocol.md

@@ -7,7 +7,7 @@ created: Tuesday, August 06, 2024
 
 > The Link Layer is the lowest level of the network stack that makes up the
 > Internet Protocol Suite. It is concerned with the physical and logical
-> connections between [hosts](./Network_hosts.md) on the same local network.
+> connections between [hosts](Network_hosts.md) on the same local network.
 
 The physical and logical connections are known as **Links**.
 

neuron/7f1b1cb6-21bf-4030-bc1f-2652dc5970ea/MAC_addresses.md

@@ -8,7 +8,7 @@ created: Tuesday, August 06, 2024
 A Media Access Control (MAC) address is a physical address in contrast to, say,
 an IP address which is logical.
 
-Each device on a [local network](./Link_Layer_of_Internet_Protocol.md) has a MAC
+Each device on a [local network](Link_Layer_of_Internet_Protocol.md) has a MAC
 as a unique identifier. It is a hardware-based, physical attribute of the
 device, typically permanently encoded onto a non-volatile memory chip attached
 to the ![network_card](static/Network_card.md).

neuron/7f1b1cb6-21bf-4030-bc1f-2652dc5970ea/Magnetic_tape.md

@@ -6,7 +6,7 @@ created: Monday, September 23, 2024
 # Magnetic tape
 
 Used for data storage in early digital computers (broadly from the
-[UNIVAC](./The_History_of_Computing_Swade.md)) era until the mini-computer era.
+[UNIVAC](The_History_of_Computing_Swade.md)) era until the mini-computer era.
 
 While the UNIVAC was not the first to use magnetic tape, it popularised the
 method due to its success and high profile.

neuron/7f1b1cb6-21bf-4030-bc1f-2652dc5970ea/Monitor_DNS_resolution_and_internet_connectivity_script.md

@@ -17,7 +17,7 @@ created: Monday, January 13, 2025
 done
 ```
 
-See [ping](./Ping.md) for more details on what this is doing.
+See [ping](Ping.md) for more details on what this is doing.
 
 The `host` command contacts a DNS server and does a reverse lookup for the
 IP-address of the human-readable domain name.

neuron/7f1b1cb6-21bf-4030-bc1f-2652dc5970ea/Network_card.md

@@ -10,12 +10,12 @@ _network adapter_ is the hardware device that allows a computer to connect to a
 network.
 
 They are the physical interface between the computer and the network
-[link](./Link_Layer_of_Internet_Protocol.md), e.g. WiFi or ethernet.
+[link](Link_Layer_of_Internet_Protocol.md), e.g. WiFi or ethernet.
 
-They can be internal and built into the [motherboard](./Motherboard.md) or
+They can be internal and built into the [motherboard](Motherboard.md) or
 external as in the case of USB adaptors.
 
-Each network card has a unique [MAC address](./MAC_addresses.md) to identify the
+Each network card has a unique [MAC address](MAC_addresses.md) to identify the
 device on the network.
 
 Network cards on consumer-grade devices typically utilise the devices resources

neuron/7f1b1cb6-21bf-4030-bc1f-2652dc5970ea/Ping.md

@@ -6,7 +6,7 @@ created: Monday, January 13, 2025
 # Ping
 
 `ping` is perhaps the most basic network debugging tool. It sends
-[ICMP](./ICMP_Protocol.md) echo request packets to a recipient host.
+[ICMP](ICMP_Protocol.md) echo request packets to a recipient host.
 
 If the recipient receives the packet and is configured to reply, it sends an
 ICMP echo response packet in return.

neuron/7f1b1cb6-21bf-4030-bc1f-2652dc5970ea/Printing_values_in_C.md

@@ -21,5 +21,5 @@ print("%d", age)
 
 ```
 
-The `%d` is an example of a [format specifier](./zk/format-specifiers-in-c.md).
+The `%d` is an example of a [format specifier](format-specifiers-in-c.md).
 It is the decimal integer format specifier.

neuron/7f1b1cb6-21bf-4030-bc1f-2652dc5970ea/Python_package_management.md

@@ -11,6 +11,8 @@ tags: [python, data-types]
 - The alternative is the native `pip` but you have to create virtual
   environments (`venv`) to manage packages at different versions.
 
+## venv
+
 To make use of virtual environments in `pip` you have to create the virtual
 environment before installing anything:
 
@@ -37,6 +39,20 @@ Now you can install packages:
 pip [library_name]
 ```
 
+### Using venv after a system upgrade
+
+If you update your system's version of Python, this can cause `venv` to stop
+working. Resolve as follows:
+
+```
+deactivate  # leave venv env if in it
+rm -rf venv  # remove venv
+python -m venv venv # reinstall venv
+source venv/bin/activate
+python -m ensurepip --upgrade # explicitly install pip
+pip install - e.
+```
+
 ## requirements.txt
 
 The `requirements.txt` file is similar to the `package.json` in Node projects.

neuron/7f1b1cb6-21bf-4030-bc1f-2652dc5970ea/Register_and_cache_memory.md

@@ -36,4 +36,4 @@ principle that what has been previously used by the CPU will be requested again
 soon. If the CPU has just asked for an instruction at memory location 555 it's
 very likely that it will next ask for the one at 556, and after that the one at
 557 and so on. The cache's controller circuits therefore go ahead and fetch
-these from slow [DRAM to fast SRAM](./DRAM_and_SRAM_memory.md).
+these from slow [DRAM to fast SRAM](DRAM_and_SRAM_memory.md).

neuron/7f1b1cb6-21bf-4030-bc1f-2652dc5970ea/Resistance.md

@@ -4,7 +4,7 @@ tags: [physics, electricity]
 
 # Resistance
 
-- Resistance is opposition to the flow of [current](./Current.md).
+- Resistance is opposition to the flow of [current](Current.md).
 
 - Different materials have different levels of resistance. For example glass and
   rubber are excellent resistors whereas silver and copper offer little

neuron/7f1b1cb6-21bf-4030-bc1f-2652dc5970ea/SAM.md

@@ -8,8 +8,8 @@ SAM stands for **serverless application model**. It is a framework developed by
 AWS to simplify the process of building, deploying and managing serverless
 applications. It provides a concise syntax for defining the components of a
 serverless application, such as
-[Lambda functions](zk/Lambda_programming_model.md),
+[Lambda functions](Lambda_programming_model.md),
-[API gateway](/zk/AWS_API_Gateway.md) and database tables.
+[API gateway](AWS_API_Gateway.md) and database tables.
 
 The SAM infrastructure is defined in a YAML file which is then deployed to AWS.
 SAM syntax gets transformed into CloudFormation during the deployment process.
@@ -119,7 +119,7 @@ HelloWorldFunction:
           Method: get
 ```
 
-This details the location of the [handler function](/Lambda_handler_function.md)
+This details the location of the [handler function](Lambda_handler_function.md)
 which is contained at the path `hello-world/app.js`:
 
 ```js
@@ -239,7 +239,7 @@ receive one file as an input. The packaging process consists in creating that
 single file.
 
 The packaging proces will first archive all of the project artefacts into a zip
-file and then upload that to [S3](zk/AWS_S3.md). A reference to this S3 entity
+file and then upload that to [S3](AWS_S3.md). A reference to this S3 entity
 is then provided to CloudFormation.
 
 ![](static/s3-package-again.svg)
@@ -261,7 +261,7 @@ to add my own naming but it doesn't comply.)
 In order to work with your application locally without actually sending requests
 to AWS and using credit, you can run a local instance.
 
-See [Local AWS Development with SAM](zk/Local_AWS_development_with_SAM.md).
+See [Local AWS Development with SAM](Local_AWS_development_with_SAM.md).
 
 ### Deploy
 

neuron/7f1b1cb6-21bf-4030-bc1f-2652dc5970ea/Terraform.md

@@ -8,7 +8,7 @@ created: Saturday, November 16, 2024
 ## Authentication
 
 Terraform will default to the currently active AWS user providing you have your
-[AWS credentials](/zk/AWS_CLI.md) set-up.
+[AWS credentials](AWS_CLI.md) set-up.
 
 ## Creating resources
 

neuron/7f1b1cb6-21bf-4030-bc1f-2652dc5970ea/The_History_of_Computing_Swade.md

@@ -563,7 +563,7 @@ that would go on to work at IBM.
 
 Donald Knuth dedicated _The Art of Computer Programming_ to the 650.
 
-It used [magnetic drum memory](./Magnetic_drum_memory.md) along with
+It used [magnetic drum memory](Magnetic_drum_memory.md) along with
 vacuum-tubes.
 
 ### IBM 1401 (1959)

neuron/7f1b1cb6-21bf-4030-bc1f-2652dc5970ea/The_kernel.md

@@ -8,9 +8,9 @@ tags:
 
 # The kernel
 
-Within the [hierarchy of the OS](./Basic_model_of_the_operating_system.md), the
+Within the [hierarchy of the OS](Basic_model_of_the_operating_system.md), the
 kernel acts as the primary mediator between the hardware (CPU, memory) and
-[user](./User_Space.md) [processes](Processes.md). Let's look at each of its
+[user](User_Space.md) [processes](Processes.md). Let's look at each of its
 responsibilities in greater depth:
 
 - process management

neuron/7f1b1cb6-21bf-4030-bc1f-2652dc5970ea/VirtualMemory.md

@@ -11,10 +11,10 @@ Virtual memory is an abstracted and idealised representation of the physical
 memory capacity of a machine that is presented to user space for its memory
 operations.
 
-When an OS implements virtual memory, [processes](./Processes.md) in
+When an OS implements virtual memory, [processes](Processes.md) in
-[user space](./User_Space.md) cannot directly read or write to the physical
+[user space](User_Space.md) cannot directly read or write to the physical
 memory. Instead they execute memory operations against virtual memory and the
-[kernel](./The_kernel.md) translates these into the actual operations against
+[kernel](The_kernel.md) translates these into the actual operations against
 the memory hardware.
 
 The main benefits:
@@ -25,9 +25,9 @@ The main benefits:
   that memory cannot be accidentally corrupted by other processes in user space.
 
 Because the physical memory is abstracted, it can be the case that the physical
-[memory addresses](./Memory_addresses.md) are non-contiguous or even distributed
+[memory addresses](Memory_addresses.md) are non-contiguous or even distributed
 accross different hardware components (such as the
-[cache](./Register_and_cache_memory.md) and [swap](./Swap_space.md)). Despite
+[cache](Register_and_cache_memory.md) and [swap](Swap_space.md)). Despite
 this, the memory addresses will appear contiguous in virtual memory. Each user
 space process is presented with the same range of available memory addresses and
 the same total capacity.

neuron/7f1b1cb6-21bf-4030-bc1f-2652dc5970ea/What_is_memory.md

@@ -14,7 +14,7 @@ the program's **instructions** and **related data**. This is the role of memory.
 The data that comprises a program is a series of bits. The basic unit of memory
 storage is a **memory cell**: a circuit that can store a single bit.
 
-[RAM](./DRAM_and_SRAM_memory.md) memory is _volatile_ : the memory is only
+[RAM](DRAM_and_SRAM_memory.md) memory is _volatile_ : the memory is only
 retained whilst the computer has a power supply and is wiped when the computer
 is rebooted. This contrasts with the memory of the harddisk which is
 non-volatile and is retained after a reboot.

neuron/7f1b1cb6-21bf-4030-bc1f-2652dc5970ea/Working_with_JSON_in_Python.md

@@ -12,7 +12,7 @@ Equivalent to `JSON.parse()` in JavaScript.
 
 Will error if the input string is not properly formatted JSON. This will be
 `json.JSONDecodeError`, a subclass of the `ValueError`
-[exception](./Error_handling_in_Python.md)
+[exception](Error_handling_in_Python.md)
 
 ## `json.dumps()`
 

neuron/7f1b1cb6-21bf-4030-bc1f-2652dc5970ea/a4601796_trapdoor_functions.md

@@ -5,7 +5,7 @@ created: Friday, December 20, 2024
 
 # a4601796_trapdoor_functions
 
-How does [public key cryptography](./bbdcb54f_public_key_cryptography.md)
+How does [public key cryptography](bbdcb54f_public_key_cryptography.md)
 achieve the feat of making the encyrpted data only decipherable in one
 direction. In other words how come the same data can be encrypted with one key
 but only decryptable by another?

neuron/7f1b1cb6-21bf-4030-bc1f-2652dc5970ea/index.md

@@ -13,12 +13,13 @@ computer science.
 
 ![not-by-ai-badge](static/not-by-ai-alternative--light.svg)
  
-**Build ID:** cd5cdd66-905b-4f1f-b8e8-3a11ad507325
+**Build ID:** 7f1b1cb6-21bf-4030-bc1f-2652dc5970ea
 
-**Published:** Mon 13 Jan 2025 20:54:48
+**Published:** Thu 16 Jan 2025 07:08:08
 
 ### Recent edits 
 
+- [[Python_package_management]] 
 - [[Ping]] 
 - [[Monitor_DNS_resolution_and_internet_connectivity_script]] 
 - [[ICMP_Protocol]] 
@@ -30,7 +31,6 @@ computer science.
 - [[Weaving_the_Web_Berners_Lee]] 
 - [[738d0481_sound_recording_as_wave_phenomena]] 
 - [[Audio_file_formats]] 
-- [[Binary_encoding_of_sound]] 
 
 
 ### All notes (517) 

neuron/7f1b1cb6-21bf-4030-bc1f-2652dc5970ea/systemd.md

@@ -12,7 +12,7 @@ tags:
 Once the [boot process](Boot_process.md) has completed and the bootloader has
 located the kernel and injected it into memory the first user space program
 runs: `init` (for _initialisation_). `init` is a [daemon](Daemons.md)
-[process](./Processes.md) that continues running until shutdown and is
+[process](Processes.md) that continues running until shutdown and is
 responsible for starting all the processes that are prerequisites for user
 space. For example: network connections, disk access, user logins etc. `init` is
 the parent of all processes: PID1. Whilst it does a lot of its work in quick

zk/Python_package_management.md

@@ -11,6 +11,8 @@ tags: [python, data-types]
 - The alternative is the native `pip` but you have to create virtual
   environments (`venv`) to manage packages at different versions.
 
+## venv
+
 To make use of virtual environments in `pip` you have to create the virtual
 environment before installing anything:
 
@@ -37,6 +39,20 @@ Now you can install packages:
 pip [library_name]
 ```
 
+### Using venv after a system upgrade
+
+If you update your system's version of Python, this can cause `venv` to stop
+working. Resolve as follows:
+
+```
+deactivate  # leave venv env if in it
+rm -rf venv  # remove venv
+python -m venv venv # reinstall venv
+source venv/bin/activate
+python -m ensurepip --upgrade # explicitly install pip
+pip install - e.
+```
+
 ## requirements.txt
 
 The `requirements.txt` file is similar to the `package.json` in Node projects.