Memory & Storage: Crash Course Computer Science #19
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Күн бұрынPre-order our limited edition Crash Course: Computer Science Floppy Disk Coasters here! store.dftba.co...
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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@jamespilcher5287 7 жыл бұрын
"you may recognise this as a save icon but these were once physical objects" OH COME ON! When did I become prehistoric?! :)
@enoque2479 7 жыл бұрын
James Pilcher I never saw a floppy disk in real life '-' I'm 16 btw
@Huntracony 7 жыл бұрын
Enoque Sousa, I occasionally used them, and I'm 18.
@IceMetalPunk 7 жыл бұрын
Enoque Sousa I don't like you now...
@rydohg 7 жыл бұрын
I've only seen floppy disks in videos and as a save icon. I'm 16
@bearianna 7 жыл бұрын
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 6 жыл бұрын
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 6 жыл бұрын
I once overheard a little boy calling the floppy disk icon the "Transformer save button", so yep.....
@AudioGardenSlave123 7 жыл бұрын
Insane how difficult the climb to modernity has been in all aspects.
@francoislacombe9071 7 жыл бұрын
I learned to program in FORTRAN on punch cards. I think Fred Flintstone was attending the same school.
@MrBratkenSolov 4 жыл бұрын
Remember when there were no wheels?
@kelliefay7625 7 жыл бұрын
Carrie, you talked about Floppy disks like they were fossils. I suddenly feel very very old.
@jamespilcher5287 7 жыл бұрын
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 7 жыл бұрын
And she didn't even have an 8" or 5.25". Those REALLY flopped!
@beretperson 7 жыл бұрын
Right? I don't recognize them from the save icon, I recognize them from HAVING USED THEM FOR STUFF
@kelliefay7625 7 жыл бұрын
Rev. Dave Moorman I was about to say "raise your hands if you used the 5.25 floppies. 😄
@zavi3rz 7 жыл бұрын
I used them to install Chip's Challenge in Windows 3.1... Oh boy my age....
@donreyes6653 4 жыл бұрын
That was the best, most witty and smart, patreon showtout I’ve ever heard! 😆
@donaldbustell3787 7 жыл бұрын
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).
@jecelassumpcaojr890 7 жыл бұрын
"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.
@weldin 7 жыл бұрын
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.
@oslonorway547 7 жыл бұрын
Oh boy, back when you ask a coworker if they had a _"Floppy disk"_ or a _"Hard disk"_ .
@EvanRustMakes 7 жыл бұрын
I have a hard disk ( ͡° ͜ʖ ͡°)
@ganaraminukshuk0 7 жыл бұрын
I have an SSD. What does that mean?
@maklasik 7 жыл бұрын
First S stands for solid. Not sure if it supposed to be that way. You should check yourself bro
@ramsofsteel3359 7 жыл бұрын
Ganaram Inukshuk solid state drive
@farhanmahalludin 7 жыл бұрын
Someone in this thread doesn't get the joke.
@jameswhitfield618 7 жыл бұрын
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 7 жыл бұрын
Your right. The video even briefly showed a sorter working. Conventionally, the sequence id number was in the right-most columns.
@varana 7 жыл бұрын
Nonetheless, manually re-sorting a few thousand punch cards is kind of annoying.
@General12th 5 жыл бұрын
If anything, it sounds like they had more smarts back then than we do now.
@SamCridlin 7 жыл бұрын
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!
@brandonbodine 7 жыл бұрын
Thanks for another great episode! The mix of history and technical detail is just wonderful. Keep them coming please.
@ishbanyadav 7 жыл бұрын
This is really helpful for Computer Science students!
@jacjessie 6 жыл бұрын
TRUE!
@amvapprentice1333 6 жыл бұрын
Really helpful! ;D
@paulvotaw3886 5 жыл бұрын
And random photographers who wondered their pictures were actually stored in tiny little bits of seeming magic!
@General12th 5 жыл бұрын
I, uh, hope it is. That's the point.
@MegaMoma 5 жыл бұрын
Yeah if they want to know how it came around, there is little no no information on how modern ram works
@pinklady7184 7 жыл бұрын
You are a great tutor, Carrie. Thanks for making this tutorial.
@crashcourse 7 жыл бұрын
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 7 жыл бұрын
Veterinary!!! I know you see me -_- !!!
@IceMetalPunk 7 жыл бұрын
If floppy disks are obsolete, then I'm an old man, so logically, floppy disks cannot be obsolete. Logic!
@Hartono25277 7 жыл бұрын
can I use the floppy coaster for recording data?
@MakeMeThinkAgain 7 жыл бұрын
I was hoping you were going to say you would take all our old floppies. I have boxes of them.
@AnonymousFreakYT 7 жыл бұрын
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?
@enjoythelife1 7 жыл бұрын
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 7 жыл бұрын
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 7 жыл бұрын
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 6 жыл бұрын
yea.. its a bit dum. some stores you can still buy them, and they are still used in many professional equipment
@quadrplax 5 жыл бұрын
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 4 жыл бұрын
@@owlredshift I already got no CDROM by 2006)digital only
@donniedarko1345 5 жыл бұрын
Currently studying computer science. This blows my mind!
@HenleyBailey 6 жыл бұрын
This series needs more views, really well put together.
@FortyTwo42 7 жыл бұрын
CrashCourse ROCKS! Hope our videos will reach your quality someday :)
@zenujong4027 7 жыл бұрын
:D
@ryanbananahands7545 7 жыл бұрын
*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.
@kurichan142 4 жыл бұрын
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.*
@mathematicalmatt 7 жыл бұрын
But how are solid state storage technologies of today not volatile?
@Huntracony 7 жыл бұрын
Yeah, I really wished they'd answer that.
@ShaunDreclin 7 жыл бұрын
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 7 жыл бұрын
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 7 жыл бұрын
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 7 жыл бұрын
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.
@brianhack5806 6 жыл бұрын
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.
@AdrianLikesFlags 7 жыл бұрын
I work for IBM Storage and am really happy to see this episode! :D
@brianhack5806 6 жыл бұрын
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).
@kyloshalo6440 6 жыл бұрын
I've a test on digital systems design on Friday. I love this lady!
@martbarnav1787 4 жыл бұрын
"If you have that much money to drop, did you know that CrashCourse is on patreon" lol that got me.
@TheDrFunkenstein 7 жыл бұрын
This series is the best. Carrie Anne you are amazing!
@lylejohnson7591 4 жыл бұрын
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.
@CiszHelion 7 жыл бұрын
9kb is wrong, its around 1kb. ;) 5:00
@kd1s 7 жыл бұрын
I was in college in the early 1980's and took a PL/I course. It was on punch cards - how archaic even then.
@benaaronmusic 7 жыл бұрын
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.
@CarthagoMike 7 жыл бұрын
I remember the times we used floppy disks. Damn, I feel old now.
@bautistakeithcharles3302 7 жыл бұрын
I have a lot of catching up to do in this series. Time to binge watch from square one ....
@mobluse 7 жыл бұрын
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 5 жыл бұрын
+1
@firestar1056 7 жыл бұрын
It would be a shame if someone where to sneeze in the room with all my punch cards.... luckily I actually use SSD
@8BitEggplant3 6 жыл бұрын
It's really interesting to me thapt the development of magnetic memory paralleled that of early audio recording from drums to disks.
@EMAngel2718 7 жыл бұрын
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.
@kamildawood4805 5 жыл бұрын
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!!
@cholten99 7 жыл бұрын
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? ;-)
@23trekkie 7 жыл бұрын
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.
@Anonymous-qw Жыл бұрын
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.
@TheTwick 7 жыл бұрын
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....
@raney150 6 жыл бұрын
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
@tylerpeterson4726 7 жыл бұрын
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.
@deltakid0 5 жыл бұрын
Really good memory hierarchy pyramid chart 8:53
@kimiyya1 7 жыл бұрын
Carrie Anne Philbim, a computer genius and great tutor. Thanks. How I after this series you can teach us programming!
@lordsnape13 4 жыл бұрын
The title of this video should be " HISTORY OF COMPUTER MEMORY & STORAGE"
@pedromartins3783 6 жыл бұрын
You sound so passionate!!!
@Roulden 7 жыл бұрын
Lots of cool and neat stuff that lead us to where we are now in the information age. Thanks for the video!
@DjangoLowe 7 жыл бұрын
You should have touched on the people that make music with old floppy drives, That would have been fun.
@Giraffinator 5 жыл бұрын
I feel superior to others for having a childhood that coincided with the tail-end of the floppy disk lifetime.
@fabienleguen 7 жыл бұрын
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
@nayotauhura4405 7 жыл бұрын
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.
@jecelassumpcaojr890 7 жыл бұрын
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".
@angeldude101 7 жыл бұрын
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?
@AungWinHtutGH Жыл бұрын
Thank you so much, I will explain my students about that!
@MediPL 7 жыл бұрын
At around 4:55 you mention that 9216 bits is 9 kilobytes, it's 9 kilobits.
@tomcombe4813 6 жыл бұрын
You're right it would be 9216÷8=1152 or just over one kilobyte
@Sordatos 7 жыл бұрын
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.
@icedragon769 7 жыл бұрын
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
@imofage3947 7 жыл бұрын
You guys should get your theme for this series played on Floppotron!
@tacozmacleo 7 жыл бұрын
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! :'(
@zerg6205 7 жыл бұрын
A fantastic watch!
@Choprajigayak 4 жыл бұрын
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!
@peka2478 4 жыл бұрын
cant unpunch a hole? she explained the process of putting tape over them in a previous video, no?
@chbrules 7 жыл бұрын
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)
@pummisher1186 7 жыл бұрын
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.
@Randalfien 7 жыл бұрын
You're awesome, great video! :D
@TheNethIafin 7 жыл бұрын
4:57 - 9 kiloBITs
@victor555117 7 жыл бұрын
Wow, even she called the intel SSD a harddrive @10:35
@DrunkCat1337 6 жыл бұрын
Don't forget: Disk is magnetic, Disc is optical. e.g. Floppy Disk, Compact Disc
@sakib2249 5 жыл бұрын
but how this SSD work. how these disks are non-volatile?
@djlapio93litlebro 7 жыл бұрын
You forgot to mention Williams tube and Selectron tube!
@greyareaRK1 7 жыл бұрын
Great show. Wonderful host.
@DeliveryMcGee 7 жыл бұрын
My first computer (a ten-year0old Tandy TRS-80) used a Compact Cassette instead of a disk drive. It was finicky, you had to adjust the gain/volume just so to make the computer read it. Apparently a bit later there was a little-used system to use VHS tapes for cheap tape backup, but it was even more finicky because of all the extra stuff going on in a VCR with the helical scan head and whatnot. Googling trying to find it, it seems the Arduino crowd are still toying with the idea, just because of the silliness of it -- I mean, you could put a full Arduino system with a multiple-terabyte SSD in a VHS tape's shell. (Which actually sounds like a fun project, I've seen Arduino/RasPi-based NES emulators in an NES cart, why not put the video-playing machine in a VHS cassette?)
@NickBriz 7 жыл бұрын
oh H311 yes! just pre-ordered those floppies!
@charlieharper92 7 жыл бұрын
4:48 : 9x1024 Bit = 9 kBit which is about 1,2 kByte
@blackbear92201 5 жыл бұрын
Great video. Thanks for posting!
@tomstieve 7 жыл бұрын
Love Crash Course. Thank you!
@NoahNobody 7 жыл бұрын
Floppy disk: "It was once a real physical object" Damn, do I feel like a dinosaur when people say things like that :D
@urvashisharma7415 6 жыл бұрын
thank you so much for this video..it was of tremendous help
@ilikebreathingtoo 6 жыл бұрын
Thanks for the episode, great information!
@unidorsalicosahedron7416 5 жыл бұрын
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.
@fujoshipeanut5074 4 жыл бұрын
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
@luxurious0346 7 жыл бұрын
ANOTHER LEVEL OF ABSTRACTION
@mr.wetdream5277 6 жыл бұрын
I was a senior in high school in 2008, we still used floppy disk
@osamagardazi1297 5 жыл бұрын
I have a question . Why there are so many short terms memories available ? Why not only one ? Why so many like Ragisters , Cache and Ram . Need your help and waiting for your reply 🙄
@emlun 7 жыл бұрын
Were punch card sequences like the SAGE program not numbered? Efficient sorting algorithms existed at the time, so that would make it lot easier to return the cards in order in case of an accident. Sure, 100 000 manual algorithm steps is still a lot of work, but a lot less than trying to sort out the mess with no guidance.
@varana 7 жыл бұрын
They were numbered, but it's rather inconvenient even with that.
@happyfakeboulder644 5 жыл бұрын
several times in the video (i posted this after hearing 6:47) where she said "-bytes" when she should have said "-bits" DIVIDE BY 8 OR END WITH BITS INSTEAD OF BYTES
@happyfakeboulder644 5 жыл бұрын
7:38 finally, you did it correctly
@Pfhorrest 7 жыл бұрын
Is that "hard drive" around 10:35 really a hard drive if it's not using hard disks inside of it? It's an SSD, not a hard drive.
@00buck80 5 жыл бұрын
Very good presentation
@blazebluebass 7 жыл бұрын
Fantastic episode!
@akhiljalan11 Жыл бұрын
At 4:58, should 9216 bits equal 9 Kilobits? (not bytes)
@pianomanpj 7 жыл бұрын
Anyone else notice that "circuit" is spelled incorrectly on the chart at roughly 11:21? It's spelled "curcuit". Whoops!
@AlohaBlockchain 4 жыл бұрын
I play this when I can't sleep.
@danieljebadoss3084 5 жыл бұрын
Very useful
@huge_aubergine 7 жыл бұрын
But aren't those acoustic delay lines power dependent? They were used for the same purpose as we use RAM today, right?
@memelordbatgrootnyoda7360 7 жыл бұрын
One time in my computer class, I got confused between Moore's Law and Murphy's Law
@mbyb6817 7 жыл бұрын
Not to be pedantic, but I computed the size of the "largest punch card based application" to be approx 7,15 MB and not 5MB as reported in the video. Did I calculate it wrong?
Дима Масленников
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Branch Education
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