What Is the Real Meaning of Booting a Computer?
Booting
When starting a computer, we say that it boots. This seems to come from bootstraps, the parts used to pull boots on more easily. Here, bootstraps are not shoelaces.
Bootstrapping - Computing https://en.wikipedia.org/wiki/Bootstrapping#Computing
Then why, and through what process, did the computer boot process come to be called bootstrapping? It seems the exact facts are not known.
There are several theories. First, there is a famous paradoxical expression in English, “Pull oneself up by one’s bootstraps”. At first glance it seems possible, but in reality it is impossible; it is used to mean an absurd and unrealizable method.
Later, this phrase began to be used with another meaning. Around 1922, it was reportedly used to mean a way to improve oneself independently without help from others.
Bootstrapping - Etymology https://en.wikipedia.org/wiki/Bootstrapping#Etymology
Tall boots may have a tab, loop or handle at the top known as a bootstrap, allowing one to use fingers or a boot hook tool to help pulling the boots on. The saying “to pull oneself up by one’s bootstraps”[3] was already in use during the 19th century as an example of an impossible task. The idiom dates at least to 1834, when it appeared in the Workingman’s Advocate: “It is conjectured that Mr. Murphee will now be enabled to hand himself over the Cumberland river or a barn yard fence by the straps of his boots."[4] In 1860 it appeared in a comment on philosophy of mind: “The attempt of the mind to analyze itself [is] an effort analogous to one who would lift himself by his own bootstraps."[5] Bootstrap as a metaphor, meaning to better oneself by one’s own unaided efforts, was in use in 1922.[6] This metaphor spawned additional metaphors for a series of self-sustaining processes that proceed without external help.[7]
The Real Meaning of Bootstrapping
In summary, it seems to have been used with two broad meanings.
- An impossible or foolish method
- A method of improving oneself independently
Now consider the boot process of early computers.
- In a computer with only CPU/RAM/IO
- Immediately after power is turned on, RAM contains no program data.
- A loading program is needed to load a program from external storage.
- Another loading program is needed to load the loading program into memory.
Because this situation occurs, the computer cannot operate satisfactorily by itself at all. This situation recalls the first meaning of “Pull oneself up by one’s bootstraps”.
In practice, code was written one byte at a time using built-in toggle switches and then executed after input was complete. There were probably also cases where code was written to read data from external storage such as punch cards or tape, load it into RAM, and then execute the loaded content.
If there is a mechanism that automatically loads a program into RAM from external storage, then when power is turned on and a basic button is pressed, a dedicated circuit reads data from the external storage. After loading the program from external storage into RAM, the CPU is initialized and processing starts from the default memory address. If necessary, another program is loaded from another input device to perform more complex processing. This recalls the second meaning of “Pull oneself up by one’s bootstraps”.
Wikipedia also explains it in this sense. https://en.wikipedia.org/wiki/Bootstrapping#Computing
All of the above is speculation, but in the early days of computers there were probably many situations like this.
People working in the field at the time may have felt, “This really is a pull itself up by its bootstraps situation.”
Perhaps that is why the word bootstrapping started to be used casually and gradually took root.