What are Heads, Tracks, Cylinders & Sectors? [Byte Size] | Nostalgia Nerd

[@RetroGamingMuseum]

I remember using the dos commmand „park“, it was used to position the head of the harddrive away from the disk to prevent damage to the disk when the computer were turned off.

[@onlyeyeno]

@Nostalgia Nerd. Thanks for another entertaining and informative video. That said I suspect that You mixed the terms when saying (@7:09) that: "Zone bit recording was introduced which introduced different number of TRACKS PER SECTOR". Shouldn't that rather have been that it "introduced different numbers of SECTORS PER TRACK" ?? Or am I totally lost ? Best regards.

[@omairtech6711]

Yeah, I noticed that as well. This video, although well made, has quite a few subtle mistakes.

[@MellowGaming]

BRB... finding Nostalgia Nerd's house. Not seeing this lady with her shopping bags in a cart...

[@GetMoGaming]

So `cluster size` >= `sector size`? But which of these parameters (CYLINDER BLOCK CLUSTER SECTOR) are hardware-specific? i.e. not adjustable via driver/software.

[@sangamshrestha143]

It is already mid night. Watched twice to understand clearly. Very helpful video, thanks.

[@musicalentities]

Hard Drives are so interesting to me. Good video! I love this channel. :)

[@painreliever83]

You're getting better at these. Delivery has slowed down noticeably from the earlier Byte-size videos which makes it easier to follow and sound less like you're just reading out a Wikipedia article.

[@1harshchauhan]

Is it a typo at 4:26......36 tracks per sector OR 36 sectors per track?

[@Perplexer1]

4:30 "Tracks per sector" ???

[@nrjacobs2025]

yeah I caught that as well. Since a track is comprised of many sectors and each sector is of a fixed 512-byte size, the outermost track has 36 sectors and the innermost has 18 sectors

[@itsaPIXELthing]

Awesome vid, Pete! :) Cheers!

[@adityasalunkhe8156]

nice presentation, 3:45 should be *CYLINDERS* instead of *TRACKS* because here *Total number of tracks = cylinders x total heads*

[@GetMoGaming]

Do you mean it should say "tracks per surface" (== cylinders) rather than just "tracks" (== tracks per surface x platters x 2 sides )?

[@BollingHolt]

1:57 The old, four-colored Amstrad disks!!! I miss my old Amstrad!

[@Daniel15au]

Great video! In old BIOSes, I remember having to manually configure the disk settings. However, I also remember the BIOS having preconfigured settings for various hard drive types. Why did they have that? Was that just for convenience, or was there a reason behind it?

[@Nostalgianerd]

Daniel Lo Nigro after dedicated hard drive boards went out of favour, the on board ide took up the task and often held a number of CHS settings to allow correct drive communication in stead of logical block addressing compatibility. I believe.

[@Daniel15au]

Thanks for the reply! I was actually thinking of "hard drive type numbers" (eg. www.minuszerodegrees.net/5170/hdd_type/5170_hdd_type.htm) but your reply was very useful too :D

[@Nostalgianerd]

I think it's the same thing. Those numbers referred to the specific requirements for the BIOS and allowed it to drive the drive, if you will. You can see in that chart that each number refers to a drive with a differing cylinder and head count, etc.

[@ijabbott63]

The type numbers were needed for the old ST-506 / ST-412 interfaces that were a lot dumber than the later IDE/ATA and SCSI interfaces. For the later interfaces, the host controller (separate card or built in to the motherboard) could read the necessary configuration information from the disk drive itself. As disk capacities increased, physical CHS values got replaced with logical CHS values - no drive really had 255 heads although that is what they often reported! For the older interfaces, a simple type number was easier to enter than a list of configuration numbers. The drawback was the inflexibility of having a fixed list of type numbers in the BIOS settings.

[@KuraIthys]

I remember a lot of my computers had autoconfig functionality - as in the BIOS would work out the disk settings automatically. Usually this worked, but sometimes it didn't, and then you'd have to scramble to figure out what the settings actually were. Which... In the worst case meant removing the drive from the computer, noting what the label said, then writing it down... Ah, old computers... So many ways to frustrate and confuse you. XD I think the best one was old VGA monitors since they were very restricted in the graphics modes they supported. And... The graphics cards often were not. Soooo.... It was fully possible to destroy your monitor by using an unsupported resolution... Just as well at some point monitors started to have protection circuitry for that. If your monitor went blank and says 'signal out of range' or something to that effect you could consider yourself lucky, because it meant your monitor was smart enough to not destroy itself. There were other things of course. IRQ and DMA conflicts could get amusing... And complicated. Especially when you had multiple devices that were rather inflexible with the settings they would support, and you had to somehow figure out a configuration that everything could actually live with... It can get very interesting when you have a graphics card, sound card and network card all deciding they need the same DMA channel...

[@pyotrleflegin7255]

Oh crikey! I remember doing this -- and setting up the BIOS by hand as well -- and it doesn't even seem that long ago! Thanks for the memories ;) !

[@antoniodesousa1731]

Great video, and great information. many thanks!!

[@nrjacobs2025]

yeah man great video, thanks for making it.

[@FernsDad]

At 4:29 - You say tracks per sector, don't you mean sectors per track?

[@shipguy55]

I contributed subtitles for this video, as a thank you for your awesome content.

[@Nostalgianerd]

Well, that's mighty kind. Thank you sir!

[@johneygd]

Sectors are still used today like in ssd drives, for instance a memory block can consists out of blocks of 4MB each but that also means that if you only put just 1MB of data on it or only just 512KB on it,then you wasted already 4MB of block space,with fat32 that block are only 2MB each while with fat64 each block is only 1MB sothat if you only throw 1MB of data on it,you only wasted that 1MB space,meaning there is more space left for other stuff.

[@moazahmed7650]

you are a life saver

[@Tarukai788]

As someone who works with a Mainframe, I did always wonder what a Cylinder meant, since it's referred to in regards to our DASD storage for it. Now I know. Thanks!

[@henrike8760]

Yes Byte Size my favorite. Thanx.

[@Jeetu0301]

Woww I MEAN just Wowww. Felt like I saw an interesting documentary which taught me a lesson of my exam.

[@K33n3]

Sneaky peak at Sheringham right at the start. Nice place.

[@krankymann]

I remember having to manually park disks before shutting the machine down - all you kids are spoiled with your self parking drives.

[@Nostalgianerd]

Yes indeed. I found one of my old DOS utilities... PrkDsk the other day. Used to give me supreme satisfaction running that before power off.

[@mittfh]

In my final year of High School, I was a volunteer student administrator for a BBC network (8x Master 128s, 3x Master Compacts) running on Ethernet connected to a Level 4 fileserver. On my last day, I shut down the fileserver but forgot to release the disks first. Unsurprisingly, I never found out what happened the first day back in September when the network manager would have tried booting it up again... Incidentally, elsewhere in the school was an English department Archimedes network, where the computers had been configured to play HAL 9000's "I am completely operational, and all my circuits are functioning perfectly" on boot - of course, as each computer took a slightly different length of time to boot, the end result was a chorus of 16 slightly out of sync renditions of that phrase...

[@ijabbott63]

I remember having old hard drives that suffered from "stiction", where the drive wouldn't spin up when you turned on the PC. The fix I used was to give the PC a sharp twist to loosen up the bearings before turning on the PC!

[@BertGrink]

mittfh i love your 'HAL9000' story :D

[@ironcito1101]

I believe I used the command "diskmon /park" or something similar. It wasn't really necessary on a home computer running DOS, however, because there was no swap file or anything like that. For most of my DOS years, I just turned off the computer without parking, and nothing ever went wrong. It became more necessary when swap files, multitasking, background processes, etc. were introduced with more modern OSs. I remember the orange-on-black "It's now safe to turn off your computer" on Windows 95, before I had a computer that could turn itself off.

[@BakoomishCips]

How's the song in the background called?

[@staticyrro]

I'm so glad we've left behind the horrors of CHS.

[@laharl2k]

but how did the controller address the data it needed? afaik the pata cable works with an address and data line. I've never read about having to specify a track sector or cylinder to get the data you want

[@BertGrink]

As you're referring to PATA, it means that you're talking about IDE drives which essentially had their own on-board computer. This computer in turn translates back and forth between the logical block numbers and the actual, physical CHS parameters. As Nostalgia Nerd mentioned, you'll never see a harddrive with 255 physical heads, although many, if not all, IDE drives report this value to the host PC (or MAC). IF there were such a beast, it would have 128 platters, and be perhaps 5 inches tall! Thus it's safe to say that the other values reported by the drive are equally fictitious! :D I hope this helps your understanding, but feel free to aks further questions. P.S. Incidentally the term 'IDE' stands for Integrated Drive Electronics.

[@magnum333]

KEEP IT UP

[@Architector_4]

That pixellated outro is iust plain awesome.

[@awilfox]

1:14 NetBSD! 😻

[@darrencafferty]

I notice by the beginning the shot of Sheringham, I didn't realise you were a local lad

[@mysmallcap]

Thanks

[@gogochannel1959]

finally someone actually says how hard drives works.

[@NeerajSharma-oz1mm]

Sir can you suggest a good book where I can read all about these sorts of things..

[@paulgascoigne5343]

don't cds write from the centre outwards? the animation showed the disc being written outside in..

[@georgegates526]

Nostalgia Nerd I still don't see the advantage of having a group of cylinder heads DIRECTLY below each other. Wouldn't it make more sense to stagger the heads on a contiguous slant on each level BY HAVING EACH OF THE HEAD ARMS LONGER ON EACH LEVEL.. The current, straight down view has the heads in need of being stored and organized because the information will all pass at the same time. On the other hand I don't know if the different lengths would cause "arm wobbling" because of ballistic speeds that the heads move. But they could possibly be counter balanced on the other side of the fulcrum. (Unless of course, they are written on a slant for each level??) . But that would require either more lines of code and/or hardware, and slow down the information being written/stored to the disk.

[@jnwms]

cool i learnt a new word, concentric!!

[@i_am_ironman1997]

Who decides track size and sector size while formatting the hard disk. Please answer this question

[@PinBallReviewerRepairs]

They do still sell platter hard drives it is only recently that there are Solid State Drives that get away from the old platter type that has sectors and clusters etc. I may get a SSHD when my Laptop regular platter HD goes poop and upchucks its silicon chips.

[@nonewmsgs]

But the question remains do I want to round to cylinders or MB when formatting a partition

[@HuntersMoon78]

Wonder if the person living at the last house in The Knob would be called a Knob End

[@GetMoGaming]

What's the 3 little bears rhyme?

[@sulzicamartinska274]

What is cluster?

[@LeeBondo]

I've heard of a clusterfuck!?

[@Nostalgianerd]

Basically the same thing. Usually the same number of heads.

[@bloodyl_uk]

Superb reply...

[@ijabbott63]

Physical heads or logical heads?

[@Jason-ti3zl]

yay early but my mom ask me to sleep....

[@1st_ProCactus]

I always thought an iphone was like a 10MB hardrive.

[@SproutyPottedPlant]

do you want to trade on the global financial market NO **skips ad** do you want to trade on the global financial market NO **skips ad** do you want to trade on the global financial market NO **skips ad** sorry 😁 anyone else get that ad over and over along with wix and uber?

[@Sb129]

Lolz, shopping trolley

[@TheJamieRamone]

Tracks per sector? Don't u mean sectors per track?

[@Nostalgianerd]

Jamie Ramone mayyybeeee

[@TheJamieRamone]

Oh, were u talking bout the drives that implemented freme-fraze technology? :P (Just never gets old XD)

[@Nostalgianerd]

Hahahahaha

[@okaro6595]

IDE drives used sectors and heads but these were just made up numbers. The actual geometry was different.

[@dagrubar]

Huh, tracks per sector? It's sectors per track, isn't it? kzbin.info/www/bejne/nZWYp36ll9KNabM

[@sarreqteryx]

I'm sure you mean sectors per track, not tracks per sector…

[@zoiuduu]

LIE!!!!, sektor is a character in mortal kombat

[@Nostalgianerd]

SEEEEKKKKTOOOOORRRRR

[@refractionpcsx2]

I think your hard drive is broken.. :P

[@azhorsley]

So hard drives are glorified record players then. I'll stick to my 33rmps.

[@Nostalgianerd]

Sound choice. Scratching platters with your hands doesn't equate to mad mixing skills.

[@Tarukai788]

Not with that attitude it doesn't. :P

[@chrisfeltner]

who formats there hard drive to 4096? 512 all the way

[@Conenion]

At 0:52 he is talking about *physical* sector size. Not logical (i.e. software only) sector size used by the file system of your choice. At around introduction of 1 tera byte drives, hard drive manufacturers went from 512b to 4096b sector sizes to save space. Space is saved since checksums (AFAIK reed solomon is used like the one used for CDs) are over 4096b now and thus 1/8th of the amount of bytes used for checksumming is being used. (The checksumming I am talking about here, is performed by the controller of the disk.) Most current drives (like 99% or so) do not present themselves as 4k logical drives. They do what is often called "512e" which means they use 4k internally but emulate a 512b sector size drive for backward compatibility with bootloaders, OSes and file systems that can't handle anything different than 512b blocks. This has a drawback: Every time you write a 512b sector the hard drive has to write a 4096b sector.

[@WillowAlchemist]

Is that the click of death :( Ive experienced that before

[@Nostalgianerd]

I believe it is. A sad moment for mechanical drives the world over.

[@ThrakaAndy]

Even worse is the "$&%# did I just hear a click?!!?" surprise followed by nothing and 10 minutes of trying to see if you can hear it again.