Explaining Hard Drive Technologies: SMR, HAMR, ePMR & more!

[@johncundiff7075]

Wow, wake up Sunday morning and learn more about hard drives in 16 minutes than I personally knew in the last 16 years!! Mr. Barnatt has another hit on youtube!! Great video Sir!

[@rafleggy2fast486]

Let me echo that sentiment! Eating breakfast and learning about HDDs and how the state of the art is so amazing while Mr. Barnatt casually explains it to us :D Love this channel.

[@theslowmoguys]

I never fully understood SMR until watching the animation in this video 👌

[@Mae-nr7wr]

i love the giant rack NAS you guys have

[@iandron7119]

The first computer I used had a 10MB hard drive option. We couldn’t afford that so we had to stick to twin floppies. Mind-blowing video, Chris.

[@Reziac]

Worse -- 360k floppies!

[@IvyMike.]

Me to, my 486DX2 had a 10MB HDD, which was massive at the time, when game where mere KB is disk space.

[@jwo7777777]

Cassette tape storage ... FTW!!!

[@daveac]

I think I pretty much followed all of that - a tribute more to your skills in explaining Chris - than my somewhat limited skills in following! Thanks!

[@Count.Dracula46]

The greatest computer related channel in the history of KZbin. Thank you so much Professor.. ❤

[@OleMose]

Once again I became a wiser man after watching a video from your hand. Thank you Chris.

[@rivertees]

Hi Chris. The first hard drive I came across in the late 1980's was a 300MB. The drive itself was the size of a washing machine, it had 12 platters, the top and bottom surfaces not used, two were position reference surfaces and 20 data surfaces. The 'Disk Packs' were also replaceable and had to be left to come up to temperature dependent on a formula based on the outside temp and the computer room temp. There were 22 W/R heads, it was sight to see. Thanks for the update, truly educating.

[@Reziac]

My high school had one of similar description, but this was from the 1960s and held a whopping 5mb!!

[@JamaicaWhiteMan]

Best explanation I've heard so far on SMR. I finally understand the mechanics of it. Many thanks.

[@Chris.Brisson]

It is good to remember that all hard drives fail; it's just a matter of time. Keep shuffling those digital bits to fresh media from time to time.

[@redpheonix1000]

Sometimes on forums people will ask "what's the best or most reliable hard drive". That doesn't really exist, any drive can fail at any time for any reason, so instead, have a solid backup plan.

[@anthonywalker6268]

SSD's also have a limited writes.

[@albyboy4278]

​@@anthonywalker6268 and after 6 months without power SSD's star to lose bits ;)

[@arch1107]

do not forget the 3 2 1

[@alanthornton3530]

@@redpheonix1000 That's the best advice you can give :)

[@deechvogt1589]

Crhirs, I always love these explainers on the underlying technologies that drive the advancement of devices in the computing space. Thanks again for another wonderful and educational video. Cheers!

[@alanthornton3530]

Thanks Chris for the thorough explanation, I'd never heard of some of the technologies that you've mentioned, I'm totally amazed. I needed a new HDD for backups as my last drive had failed, after a lot of research I chose to buy a WD 2 TB model, I'd read about SMR so wasn't entirely sure about this. I ordered one that was stated as CMR, on receipt I checked the serial number it was an SMR drive, I wasn't best pleased so contacted the store who told me it was an error on their website they told me it was perfectly adequate for backups. Another happy Sunday afternoon :)

[@Praxibetel-Ix]

Hi, Alan! :)

[@alanthornton3530]

@@Praxibetel-Ix Morning Ford I hope everything's fine with you? I thought you do with some Duckies & a virtual hug 🦆🦆🦆🦆🦆🫂;)

[@Praxibetel-Ix]

@alanthornton3530 Things are a-ok on my end! I got a very exciting electronic thing coming today; a rechargable Roku remote with backlighting and a microphone. I'm almost 24 and here I am excited about getting a new remote. 😂🤗🦆

[@alanthornton3530]

@@Praxibetel-Ix There's nothing wrong with getting excited about a delivery, I do too especially if it's something to do with electronics or computer bits. ;)

[@Praxibetel-Ix]

@alanthornton3530 I usually get excited if it's a DVD/CD/Blu-ray or a plushie. The hardest part is waiting for the stuff to be delivered once it's "out for delivery"!

[@perrymcclusky4695]

Hurray, today I learned something about hard drives that wasn't "hard" to understand. Definitely, the technology covered in this presentation puts a new "spin" on data storage. Looking forward to your next video!

[@martinjones1390]

These drives are currently 3.5 inch form factor. Would be a hoot if manufacturers had to go back to 5.25 inch drive cases to increase capacity per platter. They would have to dust off all of the old tooling to make bigger enclosures. Would then be all sorts of issues with mounting larger sized drives all over the place. (Luckily I still have an old Fractal Design case which will accomodate 5.25 inch devices. 😁)

[@Reziac]

I had a similar thought. I'd rather have a double height drive than questionable data integrity. I've begun hoarding old cases with proper drive bays myself.

[@youreds91]

Quantum had one out in the early 2000s called the Bigfoot IIRC.

[@quantumleaper]

Think about using a 12 or 24-inch platter, as IBM did in 1956 when they had 50 disk and 24-inch platters with a whole 3.75MB of storage. What storage would be with today's tech using platters of that size and number?

[@JohnDunne001]

The differences in these drives has been an unanswered question I keep forgetting to take the time to understand - no longer! Thanks for another great video EC :D

[@edengilbertofficial]

Ahh finally 😊 my Day is officially fixed 🤝🏽 fresh upload

[@ExplainingComputers]

:)

[@therealdebater]

Excellent video, which really gives us the low-down on these technologies. Of course, besides the leaps ahead in capacity, the other side of the coin is performance. And performance is a complex subject now, since there are different application with different requirements. One drive may be fast at bursty writes but poor at sustained, another drive may be the other way around. These new huge drives might turn out to have some caveats in actual use. Keep blasting it, Chris!

[@Colin_Ames]

Very interesting, as always. I never expected to see hard drives with these capacities, but here they are. A far cry from the 20MB MFM drive I had in 1988.

[@g-r-a-e-m-e-]

I started with a 10MB hard disc in 1986. I was impressed, but within a year it failed.

[@markwhidby5148]

Great video. I notice Seagate didn't use an acronym for Superlattice Platinum Alloy Media...

[@Ollital]

I can't believe that my first hard drive had only 42MB capacity in 1989.

[@ExplainingComputers]

It is amazing how things have evolved.

[@volvo09]

I love the sounds those old drives made. I had a 42mb Seagate in an 8088 system. You could feel it rumble the desk a bit when accessing data.

[@Ollital]

@@volvo09 I had the ST-251N connected to my Amiga 500 running my bbs.

[@ImpInaBox]

I can believe that. My first hard drive was a 5.25MB 'Winchester disk' in an LSI11 based microprocessor development system. Could count as luggable if there were two of you! 🙂

[@UniverseGd]

Finally good news for HDD sector that will hopefully stay competitive in storage business.

[@andy.3407]

Thank you for a wonderful presentation on hard drive technology…. I really look forward to your weekly videos!

[@heechanlee6589]

Never noticed HHD still evolving! And Chris still keep reading the trend. Nice video!

[@volvo09]

36TB!!! Holy moley!!

[@ExplainingComputers]

And HAMR is just getting started . . .

[@Ibrahimdude]

36TB. Yeah You can Put Almost Every Videos Of Explaining Computers All In One😂

[@arch1107]

@@Ibrahimdude the 3 2 1 will become more complicated there

[@wikwayer]

But for what price

[@FlyboyHelosim]

Imagine trying to fill one at HDD write speeds...

[@josemanuelsenoransrodrigue9102]

Thanks for the new video. Storage is always interesting

[@rgbii2]

Thanks Chris for the video, never new about the CMR & SMR.

[@matthewhickok4421]

I thought I knew everything about hard drives (modern and current) but you filled in some gaps and I learned some new things! I always appreciate that. I personally own a couple of "Zip" drives and several zip-disks that are destined for the land-fill. A technology that I have always found fascinating was "Magneto Optical" drives. For some reason they never caught on in the US. I wonder why. Let me pop over and see what they cost... Oh... now I get it.

[@ronm6585]

Very interesting tech. Thank you.

[@rogerbarton1790]

Excellent descriptions. I started out as a computer engineer in 1970 working on 60MB hard drives the size of a washing machine, 3 phase mains supply, 11? inch diameter platters and 11? platters/pack. 80MB drives were just being released and we though it couldn't get any better

[@louisbaudry1106]

Has Christopher received the honor of knighthood? He truly embodies the essence of British spirit in the year 2025.

[@robertbox5399]

He doesn't live in London. Midlands are not great for awards of this nature.

[@PS_Tube]

Greetings Chris B. This video is the gold standard of explaining technology. Such comprehensive discussion of Harddrive technology! 👏🏼👏🏼👍🏼

[@ypat90]

What would do without Mr. Barnatt to unravel for us the letter soup, this time around hard drives technology? I was aware of the CMR vs. SMR debate. I had not so much paid attention to the fact that at least 8 main techniques existed today, with more to come. Great idea to tackle the issue, Chris.

[@jarozlawus]

ASMR drive, that's something new Chris ;D

[@lionelreesable]

Thank you, Chris, that was a very informative video. Best wishes.

[@gregholloway2656]

Great explanation, Chris! In 1990 I had a PC with a 60 MB drive. I can still remember using Norton’s tools to test the speed of it, at 260 kB/s. So, in 35 years, the storage capacity has increased roughly 1M times, but the speed has only increased 1000 times. I find that interesting.

[@woodwaker1]

I knew hard drives have been getting larger storage capacity, but not how it was accomplished, thanks so much for explaining this it detail. I remember my first hard drive a 32 mb that was over $300. What progress has been made!

[@niallwood]

As always, an incredibly detailed and concise video! I always assumed a hard drive, was just a hard drive - but clearly not! I agree that HDDs are here to stay, in the same context that Magnetic Tape is still used for backup and data centre storage solutions. The consumer, will likely fully transfer to SSDs, but on enterprise scale and beyond, I see the HDD and Tape's here to stay.

[@P.J.McLaughlin]

My first hard drive was a card that slotted into an IBM PC. It was 10M Bytes capacity and I thought to myself "no way I'll ever fill this up or need any more'". Ah we were such adorable computer children back then.

[@Aruneh]

Excellent video! And to think this morning I was playing around with getting a PC running with a 1080MB SCSI drive and here you are talking about 30+ TB!

[@keithlambell1970]

Thank you for your excellent summary of a complicated subject.

[@stephenhargreaves9011]

I predict that this won't be one of your best performing videos, but personally, I found it fascinating. How long before the big three manage to make a stable HD that will store each bit in a single atom.

[@sharonwolff1]

I think it will be a slow burn one. I can see people 6 month or a year from now watching it. I don't know from a cash generating point of view, how that works though.

[@davidhardaker192]

Let's hope manufacturers can equally increase their warranties, as 5 or 3 years guarantees of old seem to have slipped to 1 or 2 years on consumer models.

[@esra_erimez]

I think we should measure drive capacity by how many images of ducks they can store on them. 🦆🦆🦆

[@alanthornton3530]

Absolutely :)

[@Ibrahimdude]

So Many To Learn About HDD Technology 👍

[@wikwayer]

Another good video sir barnatt 👏

[@teemdcu5978]

WD's Employee in Thailand received considerable high wages for HD read and write head placement(manually) , Patience is absolutely necessary - as of everything in our life.

[@ouijim]

Fascinating, trying to keep up since retirement 2014 ; ) Thank You

[@judsonleach5248]

Taking a survey Sir! Am I the Only super nerd with Zero Interest in the Super Bowl Today? I'd have more fun watching paint dry!

[@Praxibetel-Ix]

Hiya, fellas! You're not alone here; I don't care much about the Super Bowl but I might catch the halftime show.

[@FlyboyHelosim]

As much as I love and still use hard drives, I cannot begin to imagine the pain of writing 30+ TB to one. The last time I had to backup just a few hundred GB had me questioning my life, or rather redundancy, choices.

[@LionwoodRetroStudio]

Interesting that these are still magnetic technology.

[@Evergreen64]

I would love to see one of those "nanophotonic" lasers!

[@pAceMakerTM]

Fascinating stuff! Thanks!

[@sbc_soc_tinkerer]

Blessed Sunday greetings everyone!

[@ExplainingComputers]

Greetings!

[@LZeugirdor]

Always was curious about this. One of the things I was told was that CMR was preferred for RAID and enterprise setups due to vibration. Using something like SMR would cause data corruption eventually and is slower. I'm not sure how particularly true that is but I've always preferred CMR because it seems like it would have less issues. I like your videos a lot, really appreciative of how in depth you go into this stuff and the format of your videos. It's like a mini class but straightforward, interesting and fun.

[@udirt]

sounds like they kinda muddled the info, but you DO have TBW ratings for SMR drives which is kinda dreadful. And they aren't super high really - lower than high endurance enterprise SSD. Not sure if one _has_ to expect a failure, but they'll be a problem for anything that has a constant data intake (backup servers spool areas where you got a few 100TB of disk and then stage down to tapes, or backup servers without disk, too. it's definititely something you need to plan for, once they've been filled it'll be icky. no idea really how vibration might play in there - the cloud shops that had the SMR archive drives also had 1000s of them and usually in worse quality chassis, they would have had to see issues. The stable performance would always be a good argument. You'd be doomed if you use SMR in a tiered storage. The rest, really idk.

[@IvyMike.]

Absolutely fascinating Chris, thank you so much.

[@markwhidby5148]

I remember in my first (and only!) job, at the end of the 70s, working with mainframe disk packs - the drives were the size of washing machines. If I remember correctly their capacity was only a few hundred Mb. A few years down the line, a 9Gb external hard drive generated quite a bit of excitement in our office. By the time I retired the Computer Science department were giving (for keeps) a Raspberry Pi to their students. Computing through the ages!

[@neilshobbyhq]

Very interesting Chris, thanks

[@NicolasChapadosGirard]

That is always interesting to know. We will talk about this in another 5 years then!

[@danielivanov930]

Louis Rossman said in one of his videos that WD Ultrastar hdd's are build as tanks and were manufactured in one of the Hitachi factories . WD accuired Hitachi . I've heard they were very reliable hdd's . I got one from 2008 that still works and has lots of hours under his belt . My WD black external hdd works fine so far too . 🙂👍

[@farhanrejwan]

wd drives are really durable, even the regular ones. my 10 y/o i3-4th gen laptop, which my dad uses now, also has a 500 gb wd hdd in it (been there since purchase, was never changed). the drive survived a few laptop-fallen-from-hand-while-running, and now shows S.M.A.R.T. fail error at boot, but still giving decent performance like nothing has happened to it at all. (yes the error means it can suddenly fail at any time, but it doesn't have any important data in it anymore.) even my current laptop has a wd drive, which is a little more than 2 years, is still running fine with a few sectors damaged (i slipped on a wet floor with the laptop in my backpack, that's where i suspect the hdd got damaged internally somehow).

[@udirt]

it was IBM -> Hitachi -> HGST -> WD The quality goes all the way back to IBM back then. Beware the SSDs though, WD killed off the 'real' HGST SSDs and only left the ones by STEC (also eaten by HGST earlier) and another vendor they ate. I still think Hitachi was not very smart selling these juwels at the time.

[@farhanrejwan]

@@udirt IBM is not only very good with researching and inventing world-changing technologies, but also very good at having them overtaken by other companies 😂 my guess is, the same is gonna happen with their latest invention - quantum computers.

[@lavina58]

Thanks 👍👌😀🍀🙌🙏

[@ExplainingComputers]

Welcome 👍

[@GYTCommnts]

1) Breathtaking technology! Thanks for explaining this complex stuff so clearly! I watched the video 3 times already and saved it in my list for future reference! 2) Is difficult to know which desktop HDDs models are CMR/PMR or SMR. The companies don't publish this reference for models easily, and that's not a good practice IMHO. 3) Drinking game: drink every time you hear "M-R" (just joking! DON'T DO IT! 😄).

[@user-retrofit]

Thanks, I learn alot from this video

[@BeOurBee]

Whoops! Slight flub at about <a href="#" class="seekto" data-time="195">3:15</a> , meant Terabytes but said Gigabytes. Not to worry, I've done the same thing before... in text, where I really have no excuse! Sorry to see AI creeping into the search results for technology issues (or at least I assume that's what prompted the mention). All of that electricity just to put bad information out there and keep from writing working people's paychecks. Thanks for taking the time to get this sorted out into an easily digestible format.

[@MichelMorinMontreal]

An other Master class... Thank you so much!

[@ronnierush9379]

Great video, you really don’t want to lose that huge amount of data without a few more backups kept in different locations. 3-TB is plenty for me 😀

[@Error42_]

Great video, I often forget which technology all the acronyms are for. You did miss PMT though, that's when SMR is in a bad mood and the write rate drops to 10MB/s because the write buffer area is full 😆 But jokes aside, this can be a problem. SMR is great for backups and archiving but it isn't possible to fill it as quickly in one go. I've seen people get caught out trying to run new year end backups to these things and wonder why the backup is still running 3 days later!

[@rsb3609]

The amount of engineering is absolutely astounding, it is beautiful,and makes me very happy.🙂

[@MikeBob2023]

Thank you, Mr. Barnatt! 🙏🏼👍🏼😊

[@udirt]

nice! so much insane technology in the disk heads these days... remember having to type in bad block tables for MFM/RLL drives?? I only had to do that a few times since IDE had already landed - but it was really a strange procedure, especially looking for any really finding that piece of paper with the list taped to the drive. and now look what those SMR drives have to do internally to even know where they put their data. 🙂 I'm glad the append block sizes are fixed that way there's at least some hope left for data recoveries but oh wow that would be annoying to have to do.

[@k4be.]

And I've once thought the 40 GB hard drive I've then just bought for my new computer is HUGE and pretty impossible to fill.

[@jamesdye4603]

I'm glad I watched the video to the end before commenting, because I was wondering about solid state phasing out mechanicals. I didn't know that development of spinners was still going on. I use SSD's as boot drives but for storage I still use mechanical drives.

[@trevorford8332]

In the 90s I was using a brother computer, it only had a 20 mb hard drive which was huge for the time. How times have changed. A 36 terabyte hard drive makes it look gigantic.

[@thewatcher5271]

Hey Man, I Swear I Was Going To Ask You When You Thought PB HDD Would Show Up Before You Said It. I So Enjoy Your Sunday Lectures On Computer Science. So Much Has Changed In 35 Years. My First Computer Had No Hard Drive, Two Floppy Drives & 640k RAM. Thank You. (Comment #119)

[@lawrenceallwright7041]

A microwave generator in the write head? Surely this is science fiction, that's impossible! Thank you as always for teaching us about the stuff that we would otherwise blindly buy from the cheapest available vendor of the Interweb.

[@saurabhsrivastv]

good for study materials

[@aldntn]

The first 1MB drive I saw was a full size 5.25. In our engineering group we puzzled over how one could possibly need that much storage.

[@brianwood5220]

And I thought SSD's were the future. They'll never get an SSD to be as cost effective as an HDD is. The seem to have given up trying, instead they are trying to increase the ability of HDD's to store more and more data. Really interesting this week, Chris. Thanks for sharing with us.

[@fuxart1224]

Excellent as usual. It would be nice to compare longevity and reliability of this system. I remember a video where you talked about it with memory media in general, that's where I learned about cmr and smr. If I remember correctly cmr is more reliable. Three different technologies: to me mamr is the winner...seems less prone to failure. WD damaged its reputation with smr..

[@nonoyorbusness]

Well amazing I remember the 10mb drives that were about the size of four house bricks!

[@macoustra1]

Thank you for finding new words I can bamboozle opponents with whilst playing Scrabble!

[@davidrichardson2681]

Hi Chris, you did not give any information on speeds. With higher density/multi platters, the drives would be able to read/write faster. Are they all still SATA at 600 MB/s? Very interesting all the same.

[@jonathane9403]

Thank you for another great video! I have a nvme drive on my system with ssd back up drives and one large mechanical drive for video and other large file back up's.

[@rickharold7884]

thats so impressive. amazing.

[@classicsamusaran3817]

Is it possible to prevent the demagnetization of HDDs 2.5" or is the demagnetization of HDDs an inevitable phenomenon caused by storage conditions (humidity and temperature of my room storage)?

[@cutlow1383]

And I thought it was chipmunks storing all those bits.

[@liliwinnt6]

<a href="#" class="seekto" data-time="135">2:15</a> the Maxtor 2F040L0 is a slim/low-profile hdd there is only one platter inside the disk, and it has only one working side thus it has only one read/write head

[@pedroanitelli]

<a href="#" class="seekto" data-time="180">3:00</a> I know this is obvious knowledge for most people here, but I didn't know you could stack platters like this, even less there are drives filled with helium! (I always had simple HD's and never cared to research about it)

[@legojenn]

Talking about HDD feeds my ADHD.

[@joshuaa3075]

The first pc I used that had a hard drive was 60mb. I remember hearing a teacher talk about getting a 10mb. Computers that did not have graphic/pictures could store a lot of data on very minuscule drives by today’s standards.

[@liliwinnt6]

<a href="#" class="seekto" data-time="52">0:52</a> ha, the classic WD 1-platter hdd

[@zetectic7968]

The reports of the death of HDD have been exaggerated for years. Back in the '90's I told my older brother I had bought a new PC with a 1.2GB HDD. His response was "you'll never be able to fill it up!" 🤣

[@thesidneychan]

12 seconds ago no views? Bro fell off. just kidding. I couldn't be happier clicking immediately on a new Explaining Computers upload! I think it's very important for people to know about SMR and its limitations. External portable HDD are no longer viable as working drives (for video editing) compared to how it was back in the early 2010s.

[@thiagoreis5208]

muito bom , valeu pela aula mestre

[@andygardiner6526]

Interesting to see how many comments reference 40 or 100MB disks from history and think they were small, despite being 10x the capacity of previous incarnations! Perhaps it would be nice to do an historic overview of the advance of computer technology at some point?

[@arch1107]

lasers, microwaves, shingles, it is alot to learn but tbh i only see a future for hard disks on servers or big nas units where ssds cant compete in size and price on home desktops i do not recomend or install anymore those hard disks, noisy, generate heat and consume lots of power, too slow for games i barely use external hard disk drives, and only for backups

[@AlRoderick]

It's interesting to think that spinning platter hard drives may go the way of magnetic tape, hardly ever used by end users but still absolutely vital to the infrastructure of the Internet. I think the most recent machine I used on a day-to-day basis that had a spinning platter hard drive on it was a PS4, everything else is all ssds and memory cards.

[@Ancientreapers]

<a href="#" class="seekto" data-time="765">12:45</a> Yeah that Seagate stuff I read about a while ago. Impressive. <a href="#" class="seekto" data-time="941">15:41</a> Hard drives are like cars. They're old technology but everyone can't live without them. I've got hard drives going back to the 80s that are still fine. I check them every now and again and so far so good. On my current system, I still use the hard drive to install the games and some apps. The NVMe is strictly for booting. They have a limited read and write cycles. You need to trickle charge them every now and again or you could risk data degradation. I also still have optical drives. I keep seeing articles and people rather making fun of who needs an optical drive anymore. I have a ton of physical media and many others do too. That's who still need those. Now floppy drives, that's a different story.

[@dnoodspodu1159]

<a href="#" class="seekto" data-time="971">16:11</a> Will you remember this vague prediction of yours and put it in the year 203X in the Explaining Computers video about first 1PB HDD models? I remember the strict need [that made me jump a little ahead of what I could afford at that time] which made me buy my first 1TB HDD tribe. I also remember the reason behind me acquiring first 1 TB SSD and for 1TB M.2. I wonder what it will be for 1PB. I am guessing that some AI related private data which I will use to e.g. replace Anne Hathaway in the Movie Interstellar with an avatar of actress Natalie Portman but acting in a manner of Sandra Bullock in the movie Gravity

[@markshade8398]

In the kid 90s there were huge "full height" 5 1/4" drives with 10 platters. But the platters were MUCH thicker thank today, spun much much slower and only measured in megabytes, not gigabytes. They could just about heat a room too because of the heat they generated. And they weighed a ton!

[@hankhulator5007]

Hi, nice explanation (as if it was not complicated enough :/). At another level, one can regret that every new technology nowadays is based upon ephemeral storage, take photos, digital is good because you can multiply the shots to get the one good picture and it costs nothing to do so, but you'll need several copies on several medium to make sure you'll be able to re-read them in several years, not to mention that medium and tech will change in this laps of time - on the other side, silvery pictures do not degrade easily and their negative, if shelved correctly, can last at least a century while costing only the temperature and humidity control, which is much less than changing tech to stay up to date and transfer from old to new. It is far from sure this kind of bargain was a real good one for the end users…

[@saurabhsrivastv]

please talk about new glass substrate storage