Registers and RAM: Crash Course Computer Science #6


Take the 2017 PBS Digital Studios Survey: Today we’re going to create memory! Using the basic logic gates we discussed in episode 3 we can build a circuit that stores a single bit of information, and then through some clever scaling (and of course many new levels of abstraction) we’ll show you how we can construct the modern random-access memory, or RAM, found in our computers today. RAM is the working memory of a computer. It holds the information that is being executed by the computer and as such is a crucial component for a computer to operate. Next week we’ll use this RAM, and the ALU we made last episode, to help us construct our CPU – the heart of a computer.


In our 16×16 Latch Matrix graphic, we inadvertently left off the horizontal row access line above the top row of latches. As a result, the highlighted line for the row at address 12 should actually be one line higher.

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  1. Mi Ku says

    I’ve been trying to learn that for ages and watched hundreds of videos and nobody explained it that clearly as you and I finally understand it. Thanks

  2. Peter Roman says

    How do you build a ram stick with matrices that small

  3. SinkBoat says

    “Another level of abstraction” -Anna

  4. Sniper Hawk Gaming says

    rip ppl who skipped to this video to know how memory works thinking this is a babies course…

  5. Rubens Alves says

    9:57 What does she mean by accessing any memory location in a "random order"?

  6. Karan Nehra says

    Are simple wires used in these logic circuits.
    How are you looping the output in the input wire? ( refer time in this video) 1:34

  7. Edbert says

    This is kinda confusing to me… and the explanation is kinda too fast…

  8. Tristan says

    For me the multiplexer doesn’t seem to cover all possible 256-bit numbers. For example, if column 1 is required for one bit, and row 3 for another bit, then automatically the bit located at row 3 column 1 will also activate, even if I don’t want to. How does this work?

  9. Abhishek shah says

    This taught me more about registers than my electronics professor ever bothered too.

  10. Bhavesh Kumar says

    I want to know that from where u studied it all…

  11. Thomas` Bouasli says

    doesn't that loop to store a 1 require the electrons to be constantly flowing? how does that work without power?

  12. Matthew Ascough says

    i hate this

  13. Romeo peter says

    The layers of abstraction gets really complex. I applaud the geniuses that have contributed to the development of computer data storage over the many years.

  14. 아네모네 Anemone says

    I found there is a problem 02:06
    Anne says Or gate can save 1, but if you again put 0,0 in A and B the output becomes 0. It is changable.

  15. Jonathan Wögerbauer says

    Actually its a decoder not a mux or?

  16. Rama Satya says

    Thank you very much. One cannot ask for a better explanation for these.

  17. Sauvik says

    Brilliant! I am learning more from 1or 2 of these 10 min videos , than I learnt in allmost months while I was in engineering college. it's mind blowing when I think about it!

  18. Filip Hedman says

    You explain this way too fast for me to understand anything but it was good anyways.

  19. Khaled Sallam says

    I've struggled so much with my software for embedded systems course because these basic concepts were unclear to me. Few minutes into the video and a huge bulb lit up in my brain and I had this AHHAAAA moment! Thank you

  20. eddiehimself says

    "The Persistence of Memory" hehe

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