Lesson plan
Continuous memory
The term continuous memory was coined by Hewlett-Packard (HP) to describe a unique feature of certain HP calculators whereby the calculator could internally sustain most, or in later models - all, of the contents of user memory (via battery-backed CMOS memory). Since its introduction on the HP-25C, this feature slowly evolved by model to eventually mean maintaining the contents of nearly all calculator memory, including system and scratch RAM, options, settings, flags, and other calculator state information. Before the introduction of the HP-25C in 1976, all calculator random-access memory (RAM) was volatile, i.e. its contents (esp. user data in storage registers and any user programs) were cleared when the calculator was turned off. Three early models with this improved, continuous memory - the HP-25C, HP-29C, and HP-19C - actually had the words " Continuous Memory " printed in conspicuous, white script on the bottom margin of their faceplates. The "C" in the model designations was to distinguish those models within HP's calculator product line. HP did not print this phrase on subsequent, featured models because the novelty of continuous memory had by then faded and also because it could no longer claim it as a feature unique to HP calculators (Texas Instruments would later call their identical feature "Constant Memory"). At introduction over the next 9 years (approx.…
Article summary
The term continuous memory was coined by Hewlett-Packard (HP) to describe a unique feature of certain HP calculators whereby the calculator could internally sustain most, or in later models - all, of the contents of user memory (via battery-backed CMOS memory). Since its introduction on the HP-25C, this feature slowly evolved by model to eventually mean maintaining the contents of nearly all calculator memory, including system and scratch RAM, options, settings, flags, and other calculator state information. Before the introduction of the HP-25C in 1976, all calculator random-access memory (RAM) was volatile, i.e. its contents (esp. user data in storage registers and any user programs) were cleared when the calculator was turned off. Three early models with this improved, continuous memory - the HP-25C, HP-29C, and HP-19C - actually had the words " Continuous Memory " printed in conspicuous, white script on the bottom margin of their faceplates. The "C" in the model designations was to distinguish those models within HP's calculator product line. HP did not print this phrase on subsequent, featured models because the novelty of continuous memory had by then faded and also because it could no longer claim it as a feature unique to HP calculators (Texas Instruments would later call their identical feature "Constant Memory"). At introduction over the next 9 years (approx.…
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Discussion questions
- Summarise the article in your own words. Which single claim would you verify first, and why?
- Which claim in this article is most likely to be revised as the sources update? How would you check its current status?
- If two sources disagreed about one of these facts, what would you need in order to trust one over the other?
Bibliography
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Key claims and bibliography are generated from the same tracked claims and sources as the article page.