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**Footnotes and Digressions**
1. The PDP-8 does have one programmer-accessible register that isn't an even multiple of 3 bits, the single-bit "link" register, but we won't be talking more about that register in this article. The term "link" in the article does not refer to this register.
2. Thus the term [octet](https://en.wikipedia.org/wiki/Octet_(computing\)), which unambiguously refers to a group of 8 bits.
3. Yes, "versions," plural. There were actually 3 major [versions of ASCII](https://en.wikipedia.org/wiki/ASCII#History), published in 1963, 1964, and 1967. Since the original PDP-8 came out in 1965 and the PDP-8/I model came out in 1968, you can see that the development of these computers coincided quite nicely with the development of ASCII itself. Thus, the PDP-8/I is one of the first machines that were aware of 7-bit ASCII as we now understand it from inception.
3. Yes, "versions," plural. There were actually 3 major [versions of ASCII](https://en.wikipedia.org/wiki/ASCII#History), published in 1963, 1964, and 1967. Since the original PDP-8 came out in 1965 and the PDP-8/I model came out in 1968, you can see that the development of these computers coincided quite nicely with the development of ASCII itself. Thus, the PDP-8/I is one of the first machines that aware from inception of what we now think of as 7-bit ASCII.
4. The most common terminal used with PDP-8s and other machines of its era was the [Teletype Model 33](https://en.wikipedia.org/wiki/Teletype_Model_33) ASR, the latter referring to the Asynchronous Send and Receive version. Although you will commonly see this referred to as an ASR-33, that is not its [proper](https://en.wikipedia.org/wiki/Teletype_Model_33#Model_33_ASR_vis-.C3.A0-vis_ASR-33) name.
5. Remember the notation: 4096 12-bit words is 6144 bytes, but we always speak of core memory in terms of words, not bytes. It's "4k" or "4 kW", not "6 kB".
6. Pro tip: every time the third digit of an octal address goes up by 2, it is referring to a different PDP-8 page: page 1 begins at address 200₈, page 2 begins at address 400₈, etc.
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