Memory & Storage: Crash Course Computer Science #19

Pre-order our limited edition Crash Course: Computer Science Floppy Disk Coasters here! store.dftba.com/products/comp...
So we’ve talked about computer memory a couple times in this series, but what we haven’t talked about is storage. Data written to storage, like your hard drive, is a little different, because it will still be there even if the power goes out - this is known as non-volatile memory. Today we’re going to trace the history of these storage technologies from punch cards, delay line memory, core memory, magnetic tape, and magnetic drums, to floppy disks, hard disk drives, cds, and solid state drives. Initially, volatile memory, like RAM was much faster than these non-volatile storage memories, but that distinction is becoming less and less true today.
CORRECTION: AT 5:00 we say "around 9 kilobytes" when we should have said "kilobits".
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[@AudioGardenSlave123]

Insane how difficult the climb to modernity has been in all aspects.

[@jamespilcher5287]

"you may recognise this as a save icon but these were once physical objects" OH COME ON! When did I become prehistoric?! :)

[@enoque2479]

James Pilcher I never saw a floppy disk in real life '-' I'm 16 btw

[@Huntracony]

Enoque Sousa, I occasionally used them, and I'm 18.

[@IceMetalPunk]

Enoque Sousa I don't like you now...

[@rydohg]

I've only seen floppy disks in videos and as a save icon. I'm 16

[@bearianna]

James Pilcher i was born in the 90's and i also remember seeing physical floppy disks, although they were slowly becoming less common

[@olympiawa]

You know you're old when you hear a kid say, "oh you 3D printed the save icon" lol. Whoever was the first person to say that deserves a high five.

[@aboxinspace]

I once overheard a little boy calling the floppy disk icon the "Transformer save button", so yep.....

[@kelliefay7625]

Carrie, you talked about Floppy disks like they were fossils. I suddenly feel very very old.

[@jamespilcher5287]

Kellie Fay it puts me in mind of Back To The Future II - "you mean you have to use your hands?! It's like a baby's toy!"

[@rev.davemoorman3883]

And she didn't even have an 8" or 5.25". Those REALLY flopped!

[@beretperson]

Right? I don't recognize them from the save icon, I recognize them from HAVING USED THEM FOR STUFF

[@kelliefay7625]

Rev. Dave Moorman I was about to say "raise your hands if you used the 5.25 floppies. 😄

[@zavi3rz]

I used them to install Chip's Challenge in Windows 3.1... Oh boy my age....

[@francoislacombe9071]

I learned to program in FORTRAN on punch cards. I think Fred Flintstone was attending the same school.

[@MrBratkenSolov]

Remember when there were no wheels?

[@donreyes6653]

That was the best, most witty and smart, patreon showtout I’ve ever heard! 😆

[@donaldbustell3787]

Re: SAGE program at 1:20 - I worked on ASUPT - Advanced Simulator for Undergraduate Pilot Training - which the US Air Force brought on line in 1973. It was the first flight simulator to have a computer generated visual display. The computers (there were three) had core memory, mag tapes, and a disk drive with a stack of nine interchangeable 12 inch metal plates. It was programmed on cards in a combination of FORTRAN and the dialect of assembly for that machine. I don't recall the exact number of cards in the total load, but I seem to remember it was more than the 63500 you quoted for SAGE. For what it's worth, the research we did on that machine to find out the best way to use simulators for pilot training led directly to the simulators used by airlines today to train their pilots and run annual emergency procedure check rides (think practicing engine out landings).

[@weldin]

Guys just remember that these crash course videos are intended for students, people who generally weren't around for floppy disks. They still probably know what a floppy disk is though. Of course you don't have to be watching these for test purposes. They're fun to watch on their own.

[@crashcourse]

Hey guys, you know what’s great - repurposing obsolete technology. We here at Crash Course HQ like floppy disk coasters so much, that we thought you might like some too. So we made a batch of limited edition Crash Course Comp Sci Floppy Disk Coasters!* Limited because, well, floppy disks are kinda tough to come by these days. So if you too want to say goodbye to cup rings and hello to low-density storage media follow the preorder link here! store.dftba.com/products/computer-science-coasters *some assembly required

[@dankmemes-su5fk]

Veterinary!!! I know you see me -_- !!!

[@IceMetalPunk]

If floppy disks are obsolete, then I'm an old man, so logically, floppy disks cannot be obsolete. Logic!

[@Hartono25277]

can I use the floppy coaster for recording data?

[@MakeMeThinkAgain]

I was hoping you were going to say you would take all our old floppies. I have boxes of them.

[@AnonymousFreakYT]

Need a donation of a few hundred more floppy disks? And/or can I download and/or buy just the labels to apply to my own floppies?

[@jecelassumpcaojr890]

"Unpunching a hole is hard", but far from impossible. My university was still using punch cards in 1980 (replaced with terminals the following year) and the lines for the punch machines would get silly near course deadlines. So I had a bag of holes collected from the punch machines (on days they weren't so busy), a razor and one reference card with all the characters punched in it. Adding a few holes and eliminating a few from a card could be done in a minute instead of waiting hours in line for a free machine.

[@ishbanyadav]

This is really helpful for Computer Science students!

[@jacjessie]

TRUE!

[@amvapprentice1333]

Really helpful! ;D

[@paulvotaw3886]

And random photographers who wondered their pictures were actually stored in tiny little bits of seeming magic!

[@General12th]

I, uh, hope it is. That's the point.

[@MegaMoma]

Yeah if they want to know how it came around, there is little no no information on how modern ram works

[@oslonorway547]

Oh boy, back when you ask a coworker if they had a _"Floppy disk"_ or a _"Hard disk"_ .

[@EvanRustMakes]

I have a hard disk ( ͡° ͜ʖ ͡°)

[@ganaraminukshuk0]

I have an SSD. What does that mean?

[@maklasik]

First S stands for solid. Not sure if it supposed to be that way. You should check yourself bro

[@ramsofsteel3359]

Ganaram Inukshuk solid state drive

[@farhanmahalludin]

Someone in this thread doesn't get the joke.

[@brandonbodine]

Thanks for another great episode! The mix of history and technical detail is just wonderful. Keep them coming please.

[@SamCridlin]

In the early 2000s I worked in a data center that made good money by using 2 tape drives to move cold storage reels to DAT. I have lived through way too many memory formats. Your coasters look way too familiar! Carrie, great series and episode!

[@jameswhitfield618]

the last 8 columns of the punch card used to number the cards in order. So, if that breeze came a long the, card puncher could be used to sort them back into the right order. They did have some smarts back then. love your stuff.

[@donfitzsimons6673]

Your right. The video even briefly showed a sorter working. Conventionally, the sequence id number was in the right-most columns.

[@varana]

Nonetheless, manually re-sorting a few thousand punch cards is kind of annoying.

[@General12th]

If anything, it sounds like they had more smarts back then than we do now.

[@donniedarko1345]

Currently studying computer science. This blows my mind!

[@HenleyBailey]

This series needs more views, really well put together.

[@pinklady7184]

You are a great tutor, Carrie. Thanks for making this tutorial.

[@FortyTwo42]

CrashCourse ROCKS! Hope our videos will reach your quality someday :)

[@zenujong4027]

:D

[@9x14S]

Meh, just another channel doing spam secretly

[@TheDrFunkenstein]

This series is the best. Carrie Anne you are amazing!

[@enjoythelife1]

I felt so old when you tslked about floppy disk not existing anymore. I mean, It wasn't that long ago. I think I used them 12 years ago.

[@owlredshift]

I'm really glad I didn't need to use floppy disks in 2005. Jesus dude, CDRW drives were $20 even back then, CDs were a dollar.

[@enjoythelife1]

Curly G Cradle Rock I live in a third world country and I only stored word documents for only one use. Also a CD burner wasn't that common in the day. So floppy disk was the best options for my needs

[@mother-fng-bonswa3612]

yea.. its a bit dum. some stores you can still buy them, and they are still used in many professional equipment

[@quadrplax]

Sounds about the same as when I was last regularly using them to transfer files. I have even used them in the past few years for plop boot manger so I could boot old PCs off a USB stick.

[@AltFromTheLimbo]

@@owlredshift I already got no CDROM by 2006)digital only

[@kamildawood4805]

Wow! This video is very educational and explained amazingly well!.. there were other information i dint find in other videos about history of memory but found in yours.. Thanks a lot!!

[@kyloshalo6440]

I've a test on digital systems design on Friday. I love this lady!

[@ryanbananahands7545]

*read in Grandpa voice* Back in my day we used to use compact disks to store memory! We did things right back then. Ahhhh, I miss the old days.

[@AdrianLikesFlags]

I work for IBM Storage and am really happy to see this episode! :D

[@Roulden]

Lots of cool and neat stuff that lead us to where we are now in the information age. Thanks for the video!

[@brianhack5806]

Even in the early 2010s, the US Navy still had, and was training people on, equipment that was using the massive hard disks of the past. A removable spindle part, with the entire unit (about as tall as me) being the rest of what we would consider a hard drive (the headers and stuff).

[@brianhack5806]

I think it was in 4th, 5th, or 6th grade that the teacher had us watch a video about penguins on a LaserDisc. ...Was supposed to be the future, but then they made DVDs. This was in the mid-1990s, so looking back on this it is a bit amusing that they thought LaserDiscs would become more common.

[@8BitEggplant3]

It's really interesting to me thapt the development of magnetic memory paralleled that of early audio recording from drums to disks.

[@ilikebreathingtoo]

Thanks for the episode, great information!

[@benaaronmusic]

I suppose 10 or 20 years from now, kids will still be learning from these awesome Computer Science videos and it will feel more like the floppy disk really was an ancient fossil.

[@tomstieve]

Love Crash Course. Thank you!

[@blackbear92201]

Great video. Thanks for posting!

[@martbarnav1787]

"If you have that much money to drop, did you know that CrashCourse is on patreon" lol that got me.

[@AungWinHtutGH]

Thank you so much, I will explain my students about that!

[@urvashisharma7415]

thank you so much for this video..it was of tremendous help

[@lylejohnson7591]

I remember when you could buy floppy discs for a dollar with programs you could try before you might want to buy the original. The little cards on Star Trek that Spock used was a prediction of floppy discs.

[@kd1s]

I was in college in the early 1980's and took a PL/I course. It was on punch cards - how archaic even then.

[@blazebluebass]

Fantastic episode!

[@zerg6205]

A fantastic watch!

[@Randalfien]

You're awesome, great video! :D

[@bautistakeithcharles3302]

I have a lot of catching up to do in this series. Time to binge watch from square one ....

[@mathematicalmatt]

But how are solid state storage technologies of today not volatile?

[@Huntracony]

Yeah, I really wished they'd answer that.

[@ShaunDreclin]

Matthew Hoiland I would love an explanation for that, I understand cds and hdds and ram easily enough, but ssds are still magic to me.

[@notmyname8348]

I think they use a special type of transistor that somehow get stuck so when you turn off your computer inside the SSD there's still electricity in there

[@IceMetalPunk]

en.wikipedia.org/wiki/Flash_memory#NAND_flash To greatly oversimplify, they use the classic gates we saw earlier in this series, but with a type of transistor that has resistive material around it, holding the charge "in place" unless a stronger charge overwrites it.

[@stachowi]

Solid state memory (e.g. flash memory) uses a floating gate transistor to trap electrons. There are lots of videos on youtube how it exactly works (it's technical and requires "quantum tunneling". But it's non-volatile because once the electrons are trapped, you don't need to supply power to retain the memory.

[@kimiyya1]

Carrie Anne Philbim, a computer genius and great tutor. Thanks. How I after this series you can teach us programming!

[@danmaster333]

Love this series, keep up the good work!

[@CarthagoMike]

I remember the times we used floppy disks. Damn, I feel old now.

[@kurichan142]

5:56 "If you have that kind of money to drop, did you know that CrashCourse is on Patreon? Wink wink-" *Stop. I'm laughing too much.*

[@fabienleguen]

Thank you for this nice videos playlist ! I am enjoyed and interested with every single episode. About this one, I can't find the episode where you spoke about solid state memory ? This is not #15. Which one is it ?? Thanks

[@greyareaRK1]

Great show. Wonderful host.

[@Anonymous-qw]

I've used IBM mainframe DASD since the mid 1980s as a programmer and knew how it worked in theory but never seen the read write heads actually working on the stacks of disks before. I remember seeing laser disks on the BBC TV show tomorrow's world when I was a kid in the 1970s.

[@CiszHelion]

9kb is wrong, its around 1kb. ;) 5:00

[@tamyboy1]

Great video!

[@tylerpeterson4726]

I heard that libraries in programming came originally from the era of punch cards with people putting together useful pieces of code into a repository where computer scientists at their university could check out that block of punch cards to use in their program.

[@pedromartins3783]

You sound so passionate!!!

[@00buck80]

Very good presentation

[@firestar1056]

It would be a shame if someone where to sneeze in the room with all my punch cards.... luckily I actually use SSD

[@Arnab913]

I first liked, then watched to see. Love you Anne...

[@mobluse]

I think Flash and SSD weren't explained in this episode. I've heard they work with trapped electrons, but it would be interesting to know in more detail.

[@laurentsmohr1803]

+1

[@cholten99]

I love how, along with the usual students, there's a lot of us folks in the comments who were learning about computers in the 70s and 80s. Next episode on cache invalidation? ;-)

[@raney150]

Floppys were definitely used after the mid 90s. I remember using them in school and at home when I was a kid back in the late 90s/early 2000s

[@NickBriz]

oh H311 yes! just pre-ordered those floppies!

[@deltakid0]

Really good memory hierarchy pyramid chart 8:53

[@EMAngel2718]

Something that should be noted about SSDs is that they're different from normal ICs in that the storage process involves essentially pushing electrons with really high force into and out of materials with really high resistance. The resulting electrostatic fields turn field effect transistors on or off, without needing moving electrons.

[@danieljebadoss3084]

Very useful

[@lordsnape13]

The title of this video should be " HISTORY OF COMPUTER MEMORY & STORAGE"

[@23trekkie]

Floppy disks old? I remember Commodore 64 and games recorded on cassette tapes! It makes no wonder why I don't remember C64 having any RPG or RTS games, considering that C64 had no hard drive (all it had was RAM and ROM memory) to save game record on it.

[@chbrules]

I saw the RAMAC 305 in action at the computer history museum up near the CA bay area. It was neato! In fact, I think I have a vid of it on my "channel" somewhere (got a lot of car vids lol)

[@TheTwick]

My first programs and data were stored on punch cards. The saving grace of dropping a stack of cards were good old rubber bands - two if you were especially paranoid. I've seen people drop large stacks of loose cards and cry and cry....

[@Giraffinator]

I feel superior to others for having a childhood that coincided with the tail-end of the floppy disk lifetime.

[@IngLauraDuarte]

Love this videos!!!

[@DjangoLowe]

You should have touched on the people that make music with old floppy drives, That would have been fun.

[@nimalkumarasinghe4970]

Thanks a lot ❤❤🙏🙏

[@angeldude101]

I only have floppy disks in my house because my dad was interested in computers when he was younger. I don't remember ever actually using one though. You mentioned that SSDs use the same technology that we already talked about, but wasn't that volatile? Can you please elaborate how flash memory works and why it's non-volatile?

[@MediPL]

At around 4:55 you mention that 9216 bits is 9 kilobytes, it's 9 kilobits.

[@tomcombe4813]

You're right it would be 9216÷8=1152 or just over one kilobyte

[@fujoshipeanut5074]

I remember trying to save word docs with loads of clip art on a floppy disk but was so confused as to why I could never save even one document while my mum was able to save lots of word docs with no pictures 😂 Eventually it clicked

[@unidorsalicosahedron7416]

11:00 Sure, the seek times may be slow by comparison, but the fastest consumer SSDs out there are about as fast in terms of bandwidth.

[@zakunknown9737]

thanks C.A.!

[@nayotauhura4405]

I worked with punch cards, and still I have nightmares of the punch machine spitting out cards in the air. Each batch job took us 9 hours to run.

[@deshantdevkota2563]

Thanks

[@Sordatos]

I'm a bit disappointed that she didn't point out that we could recognize the magnetic drums as the "loading" LED in modern computers.

[@Choprajigayak]

She Looks like a Real Sheldon's Sister! British | Big Bang Theory| I was working on ServiceNOW Storage discovery and I landed up here. Lots of hard work she's done. God Bless and keep making great videos!

[@imofage3947]

You guys should get your theme for this series played on Floppotron!

[@pummisher1186]

I remember when XP required me to install a SATA driver via a floppy (and no other way!!!) just so I could actually use my C drive. After my floppy drive died, it was easier to just install Vista which had all that built in.

[@mr.wetdream5277]

I was a senior in high school in 2008, we still used floppy disk

[@jecelassumpcaojr890]

The use of "memory" and "storage" in the video is the most popular, but is not universal. Von Neumann liked to use biological terms like "memory" and "organs" when describing computers but many people preferred "storage" and "subsystems" to avoid misleading analogies. IBM often (but not always) used "storage" to mean the same things that other companies called "memory".

[@icedragon769]

The editing introduced a continuity error. There's a callback to the "one cent per bit" factoid at 9:28 but it isn't introduced until 10:53

[@ar2_]

i hope this channel continues to eternity

[@TheNethIafin]

4:57 - 9 kiloBITs

[@ammarsyaf3035]

I tell ya you need to break for awhile after 5minute of video. The information surge my brain quickly filling the buffer

[@mattfromeurope]

*sigh* I still remember swapping 5 1/4 " floppies on my dad's C64 about 25 years ago...

[@AlohaBlockchain]

I play this when I can't sleep.

[@tacozmacleo]

I... I... Still have Floppy Disk with programs on, both in 3½ and in 5 3/4 versions.... :-| Just loooong time since I had a computer that could take the Drives! :'(

[@kumardua5898]

Hi..Could you please tell me how do we technically explain transferring the data from one memory to another. Do we short the circuit between two points and the voltage becomes same at both points. Please advise...Thanks !

[@djlapio93litlebro]

You forgot to mention Williams tube and Selectron tube!

[@charlieharper92]

4:48 : 9x1024 Bit = 9 kBit which is about 1,2 kByte

[@russemerson4872]

The mention of drum memory sparked a recollection of something I read a number of years ago - The Story of Mel: www.catb.org/jargon/html/story-of-mel.html Fascinating look at early programming.

[@DrunkCat1337]

Don't forget: Disk is magnetic, Disc is optical. e.g. Floppy Disk, Compact Disc

[@philward2098]

Now I feel ancient. i remember floppys like yesterday

[@jonathanrys6921]

Damn, I totally have some old floppy disks and I need coasters.

[@willbrine1404]

ugh, this video has made me contract a case of the olds. 👍🏽