Autosave: 2024-10-28 15:52:09

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---
tags: [world-wide-web, internet]
created: Monday, October 28, 2024
---
# 3f1b9fe5_motivation_Berners_Lee
TBL describes his motivation in creating the WWW as the desire to marry two
separate concepts/technologies: hypertext and the Internet, after both had come
of age.

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---
tags: [internet, ARPANET, ARPA]
created: Monday, October 28, 2024
---
# 4a3dc316_key_figures_ARPANET
- [Paul Baran](385af4b4_Baran_distributed_networks.md) for his work at RAND on
distributed networks as an alternative to the extant
centralised/de-centralised phone networks.
- Donald Davies at the UK Physical Laboratory for developing ideas on
#packet-switching, similar to but derived independently of Baran's work.
- Bob Kahn as the principle designer of the ARPANET, who with Vint Cerf, wrote
the TCP/IP protocols. Became director of the Information Processing Techniques
Office within ARPA/DARPA.
- Vint Cerf was head of the International Networking Group and worked on the
Network Control Protocol (the first protocol for packet switching using the
IMPs). Later joined up with Kahn on TCP/IP and the network of packet-switching
networks (early internet).

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---
tags: [internet, ARPANET]
created: Sunday, October 27, 2024
---
# 4da22434_from_ARPANET_to_Internet
By the mid-1970s many additional computer networks had emerged which also used
#packet-switching.
It was the success of ARPANET as a "proof of concept" for packet-switching that
led to these additional networks being created in other countries and contexts.
Some used different modes of transmission than the #ARPANET's phone-wire based
system such as radio waves and satellites. However this created a problem: these
networks were siloed from each other and a bridge was needed to connect them.
Those working on the ARPANET steering committee (the Information Processing
Techniques Office (IPTO) within ARPA/DARPA) began to discuss what they called a
"concatenated network" or "CATENET" that would connect these different networks
together. Thus emerged the idea of a _network of networks_ or _inter-network_.
For this to work it would be necessary to construct "gateways": routing
computers that would hand-off messages from one network to another.
This required a new protocol because the Network Control Protocol was only
designed to work _within_ the ARPANET with its IMPs. Unlike the IMPs, the
gateways would not be responsible for reconstituting packets or ensuring
reliability, this would be shifted to the hosts. The protocol was the
[Transmission Control Protocol/Internet Protocol](Internet_Layer_of_Internet_Protocol.md).
TCP would be responsible for packet assembly and disassembly and IP for routing.
The "common language" of TCP/IP and the growth in networks in addition to the
ARPANET is what formed the Internet. Different commercial groups and research
enterprises inaugurated their own networks and, one-by-one, they adopted TCP and
became accessible to each other.
As the ARPANET was retired, its individual sites either became nodes within the
Internet or they split off into sub-networks such as MILNET (which was part of
the ARPANET retained for classified military communication). The IMPs were
retired in favour of TCP/IP routers.
_The ARPANET in 1973_
![](static/Arpanet_map_1973.jpg)
_The ARPANET as part of an inter-network 1977_
![](static/internetworking_1977.jpg)
_ The ARPANET in 1977_
![](static/Arpanet_logical_map,_march_1977.png)
_The Internet in 1984_
![](static/internet_1984.jpg)

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---
tags: [internet, ARPANET]
created: Sunday, October 27, 2024
---
# 82f9c228_dissolution_of_ARPANET
By 1984, the US military became concerned about the expansion of the ARPANET and
its growing non-military applications (see the film _War Games_ released in
1983!). They split the network into the _ARPANET_ for academic research and the
_MILNET_ for non-civilian users where transmission was encrypted and protected.
Throughout the 1980s, the US National Science Foundation began promoting private
networks that used the ARPANET as their _backbone_. (Private in the sense of not
publicly-funded.)
Later, these became commercial and
[subscription-based](cfbef1c4_web_precursors.md). A plethora of ..._NETS_ grew
up (NSFNET, USENET, CSNET, TELENET etc.), all based on #packet-switching, the
ARPANET nodes as the backbone and [TCP/IP](Link_Layer_of_Internet_Protocol.md)
host communication.
These networks, although accessible to the public through subscriptions,
remained unwieldy and inconsistent to access until the Web.

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@ -5,8 +5,7 @@ tags: [CPU]
# Fetch, decode, execute, store
_Fetch, decode, execute_ is the operating cycle of the CPU. We will run through
how this works with reference to the
[CPU architecture](CPU_architecture.md).
how this works with reference to the [CPU architecture](CPU_architecture.md).
## Fetch
@ -57,8 +56,7 @@ to determine which of its circuits should be used for processing.
Now the command will be executed. The operand is copied to the Memory Address
Register and then passed to the Memory Data Register and the command is carried
out by the ALU. The activities of ALU are covered in
[CPU Architecture](CPU_architecture.md#arithmetic-logic-unit)
and the notes on
[CPU Architecture](CPU_architecture.md#arithmetic-logic-unit) and the notes on
[Logic Gates](Logic_gates.md).
## Store
@ -73,8 +71,6 @@ specify where to store the result.
- Data is stored differently depending on the instruction.
- If the instruction is iterative (e.g. adding two numbers and then multiplying
by another number), the instruction will tell the CPU to store the interim
first value in the CPU's
[registers](CPU_architecture.md#registers). As
these are part of the CPU, the data can be retrieved more readily. If the
value is not expected to be used again immediately, it goes to the DRAM or
harddisk.
first value in the CPU's [registers](CPU_architecture.md#registers). As these
are part of the CPU, the data can be retrieved more readily. If the value is
not expected to be used again immediately, it goes to the DRAM or harddisk.

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@ -13,26 +13,30 @@ computer science.
![not-by-ai-badge](static/not-by-ai-alternative--light.svg)
**Build ID:** 0368f5e0-e5f8-46f2-9cd3-c028c04a15d1
**Build ID:** 8b09146b-ecca-49b4-bbdb-d619b5566ef4
**Published:** Fri 25 Oct 2024 13:28:54
**Published:** Mon 28 Oct 2024 15:52:07
### Recent edits
- [[4da22434_from_ARPANET_to_Internet]]
- [[3f1b9fe5_motivation_Berners_Lee]]
- [[4a3dc316_key_figures_ARPANET]]
- [[82f9c228_dissolution_of_ARPANET]]
- [[Fetch_decode_execute]]
- [[Secrets_or_env_vars_in_AWS]]
- [[Working_with_directories_in_Python]]
- [[File_CRUD_operations_in_Python]]
- [[File_operations_in_Python]]
- [[Reading_files_in_Python]]
- [[With_open_in_Python]]
- [[Writing_to_files_in_Python]]
- [[Error_handling_in_Python]]
- [[File_system_error_handling_in_Python]]
### All notes (475)
### All notes (479)
- [[385af4b4_Baran_distributed_networks]]
- [[3f1b9fe5_motivation_Berners_Lee]]
- [[4a3dc316_key_figures_ARPANET]]
- [[4da22434_from_ARPANET_to_Internet]]
- [[653c0b1d_host_protocols_of_ARPANET]]
- [[82f9c228_dissolution_of_ARPANET]]
- [[861cc26e_ARPA_origins]]
- [[API_Gateway]]
- [[AWS_CLI]]

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---
tags: [world-wide-web, internet]
created: Monday, October 28, 2024
---
# 3f1b9fe5_motivation_Berners_Lee
TBL describes his motivation in creating the WWW as the desire to marry two
separate concepts/technologies: hypertext and the Internet, after both had come
of age.

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---
tags: [internet, ARPANET, ARPA]
created: Monday, October 28, 2024
---
# 4a3dc316_key_figures_ARPANET
- [Paul Baran](385af4b4_Baran_distributed_networks.md) for his work at RAND on
distributed networks as an alternative to the extant
centralised/de-centralised phone networks.
- Donald Davies at the UK Physical Laboratory for developing ideas on
#packet-switching, similar to but derived independently of Baran's work.
- Bob Kahn as the principle designer of the ARPANET, who with Vint Cerf, wrote
the TCP/IP protocols. Became director of the Information Processing Techniques
Office within ARPA/DARPA.
- Vint Cerf was head of the International Networking Group and worked on the
Network Control Protocol (the first protocol for packet switching using the
IMPs). Later joined up with Kahn on TCP/IP and the network of packet-switching
networks (early internet).

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---
tags: [internet, ARPANET]
created: Sunday, October 27, 2024
---
# 4da22434_from_ARPANET_to_Internet
By the mid-1970s many additional computer networks had emerged which also used
#packet-switching.
It was the success of ARPANET as a "proof of concept" for packet-switching that
led to these additional networks being created in other countries and contexts.
Some used different modes of transmission than the #ARPANET's phone-wire based
system such as radio waves and satellites. However this created a problem: these
networks were siloed from each other and a bridge was needed to connect them.
Those working on the ARPANET steering committee (the Information Processing
Techniques Office (IPTO) within ARPA/DARPA) began to discuss what they called a
"concatenated network" or "CATENET" that would connect these different networks
together. Thus emerged the idea of a _network of networks_ or _inter-network_.
For this to work it would be necessary to construct "gateways": routing
computers that would hand-off messages from one network to another.
This required a new protocol because the Network Control Protocol was only
designed to work _within_ the ARPANET with its IMPs. Unlike the IMPs, the
gateways would not be responsible for reconstituting packets or ensuring
reliability, this would be shifted to the hosts. The protocol was the
[Transmission Control Protocol/Internet Protocol](Internet_Layer_of_Internet_Protocol.md).
TCP would be responsible for packet assembly and disassembly and IP for routing.
The "common language" of TCP/IP and the growth in networks in addition to the
ARPANET is what formed the Internet. Different commercial groups and research
enterprises inaugurated their own networks and, one-by-one, they adopted TCP and
became accessible to each other.
As the ARPANET was retired, its individual sites either became nodes within the
Internet or they split off into sub-networks such as MILNET (which was part of
the ARPANET retained for classified military communication). The IMPs were
retired in favour of TCP/IP routers.
_The ARPANET in 1973_
![](../img/Arpanet_map_1973.jpg)
_The ARPANET as part of an inter-network 1977_
![](../img/internetworking_1977.jpg)
_ The ARPANET in 1977_
![](../img/Arpanet_logical_map,_march_1977.png)
_The Internet in 1984_
![](../img/internet_1984.jpg)

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---
tags: [internet, ARPANET]
created: Sunday, October 27, 2024
---
# 82f9c228_dissolution_of_ARPANET
By 1984, the US military became concerned about the expansion of the ARPANET and
its growing non-military applications (see the film _War Games_ released in
1983!). They split the network into the _ARPANET_ for academic research and the
_MILNET_ for non-civilian users where transmission was encrypted and protected.
Throughout the 1980s, the US National Science Foundation began promoting private
networks that used the ARPANET as their _backbone_. (Private in the sense of not
publicly-funded.)
Later, these became commercial and
[subscription-based](cfbef1c4_web_precursors.md). A plethora of ..._NETS_ grew
up (NSFNET, USENET, CSNET, TELENET etc.), all based on #packet-switching, the
ARPANET nodes as the backbone and [TCP/IP](Link_Layer_of_Internet_Protocol.md)
host communication.
These networks, although accessible to the public through subscriptions,
remained unwieldy and inconsistent to access until the Web.

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@ -5,8 +5,7 @@ tags: [CPU]
# Fetch, decode, execute, store
_Fetch, decode, execute_ is the operating cycle of the CPU. We will run through
how this works with reference to the
[CPU architecture](CPU_architecture.md).
how this works with reference to the [CPU architecture](CPU_architecture.md).
## Fetch
@ -57,8 +56,7 @@ to determine which of its circuits should be used for processing.
Now the command will be executed. The operand is copied to the Memory Address
Register and then passed to the Memory Data Register and the command is carried
out by the ALU. The activities of ALU are covered in
[CPU Architecture](CPU_architecture.md#arithmetic-logic-unit)
and the notes on
[CPU Architecture](CPU_architecture.md#arithmetic-logic-unit) and the notes on
[Logic Gates](Logic_gates.md).
## Store
@ -73,8 +71,6 @@ specify where to store the result.
- Data is stored differently depending on the instruction.
- If the instruction is iterative (e.g. adding two numbers and then multiplying
by another number), the instruction will tell the CPU to store the interim
first value in the CPU's
[registers](CPU_architecture.md#registers). As
these are part of the CPU, the data can be retrieved more readily. If the
value is not expected to be used again immediately, it goes to the DRAM or
harddisk.
first value in the CPU's [registers](CPU_architecture.md#registers). As these
are part of the CPU, the data can be retrieved more readily. If the value is
not expected to be used again immediately, it goes to the DRAM or harddisk.