Hi welcome to Tear Down! Tuesday The Humble Hard Drive. You've seen them, You probably take them for granted. This is a modern 2 tbte, 3 1/2 in hard drive that you'd get in a typical desktop computer. And they're available in pretty small sizes these days, especially for their size.

Incredible! These can go up to 4 TB in 3 1/2 in size. this is the smallest Uh current form factor You can buy the 1 8 in and they're available in up to 300 odd gab in these sizes, but that wasn't always the case. These things have had an amazing Evolution back from the mid-50s when they were developed by IBM and well I can remember buying my first uh hard drive H mid 80s or thereabouts 20 megabytes. That's not 20 Gbt.

it's 20 megabytes, let alone terabytes that you can get in these things Incredible cost me about 300 bucks or thereabouts. Nowadays you can get like, what a terabyte for under a hundred bucks. Kidding me? So these are fascinating technology. There's uh, developed in density by orders many orders of magnitude over many decades, not to mention reducing in cost as well.

So I thought we'd crack One open have a look at the technology inside, but not one of these weird ass modern ones. No. I Thought we'd go a bit Retro late' 7s, early 80s great period. Let me get it for you.

Hang on. this could take a bit. Let me move the chair out of the way. This is a real hard drive folks.

The mother of all hard drives. Let's check it out Here we go. Hang on, Bend the legs. Taada.

This is a hard drive. It's an IBM hard drive. late 70s, early 80s not sure of the exact year. Whopping 10 megabytes.

And yes, it weighs 382 kilos or about 85 lb. It's an absolute monster. We're going to tear this sucker down and uh, don't worry about me dropping it. No worries, we're in.

Australian Safety boots Beauty Let's go. And if you're wondering what this thing was worth back in late '70s early ' 80s. About a quar of a million bucks. Beauty And yes folks, I wasn't kidding.

This sucker is really worth a quar of a million dollar. Or it was worth a quarter of a million dollars back in late' 70s, early 80s and uh, this particular unit, um, was used well into the80s because they didn't want to write off the cost of these things. They were cost so so much money to uh, install, service, and maintain. Even though hard drives were dropping, uh, even big server ones like this dropping by orders of magnitude, they didn't want to ride off that Co cost very quickly, so was still used for quite some time.

And this particular one is actually from a bank. It's from the A&Z bank here in Australia and it was used to, presumably, um, store store all of the banking records. and no, it has been securely wiped. so no one's credit card numbers are on here.

Not that we do, we have credit cards back in the ' 80s, maybe bank card? H Anyway, this is an IBM let's have a look. It's an got the original sticker on it here. IBM there it is. IBM Asteris 397 x So I assume it's like a I don't know a 397 x series or something or 397 x series something like that.

I'm not sure. um, haven't been been able to find much uh info on it. so if people have any information on that, please let me know and check out this funky little temperature dial here. they've actually got it is about halfway.

It is around about 23 24 here in the lab and this is completely passive. Now this thing is an absolute Beast it. It's actually designed, um on a slide in Chazzy hence the handle here. It's got the big carry handle and handle on the other side.

So this chunk of metal on the back here is actually a slideing frame designed to slide into a rack there. and uh, we can already see some of the stuff. Perhaps we got some uh Cable in with some beauty connectors on here. Absolute Classics Look at that and uh yeah.

So this thing was designed to slide in with the aid of a tool you can't have. you know, even o Back then they still had o Ands and you couldn't have people lifting up. uh near 40 uh kilo or 90 lb uh units and you know, shoving them into racks. So they had some sort of tool to help lift them up and put them into the rack and you can see that they had uh, shock and vibration mounts as well.

You can actually see the compliance in that one. if I give it a bit of a wobble, you can see the compliance in the rubber there. that would uh, dampen shock and vibration from the both from the Uh rack and into the hard drive and also outwards and you know that would be uh, very very cleverly designed so that it does. It avoids any resonant modes during operation and all sorts of stuff.

And these would be ultra reliable. uh hard drives so you know these are in Banks storing data. This is serious and this is why these suckers cost back in those days a quarter of a million each. Do you believe it? And you may have noticed on the unit this little Port here? they've actually got one here and one on the other side of the unit.

What was this for? It's actually for pressurized Halon gas uh which is actually quite a dangerous gas to be pumped into these hard drives. so they operate under that Halon gas and it's actually a fire suppressant. Now this Halon gas wasn't just used in the hard drive itself to save the data and uh, there's the other Port over on that side there so they would pump pressurized Halon gas into this thing but the entire rooms that these things were housed in the computer server rooms uh had Halon gas as well. uh not during operation but if there was any fire then they would uh a big alarm Bell would ring off and you've got like a minute to get out of there or put on your gas mask.

otherwise you would you know you would die because they would fill the room with this Halon gas fire suppressant. They were really serious about protecting the data in these hard drives and on the back of the unit here where it uh slid in, it would slide in forward like this. presumably there would be the mate in uh multipin uh bus connector under there like that it had mate with power and something else here I'm not sure what and uh, that would be how it slots into the rack so this would be the end that goes into the rack and the uh handle would be on the other end and on the front of the unit. Here they've got like another port.

Maybe that's a uh, some sort of test port I don't know. um as in like a test like a gas Porter it might be a pressure valve or something like that. I'm not exactly sure what and uh, we've got some power coming around to this side as well. maybe going into the uh, spindle motor or something cuz we got some heavyduty cabling going on in here.

So anyway, we'll find that out when we crack this sucker open And here we go. Let's take it open now. I Think we've got one big uh, sort of, you know, diecast. um SL machined um top on the thing.

So I think if we undo these uh, hex screws around here, we should just be able to lift up this top part at least for starters. And uh, see the good stuff, the pornographic stuff. which is the platins. So let's uh, crack this thing open.

see what we get here we go. Folks, this is going to be exciting I Think it seems to be lifting off here. We go. let me see.

I don't want to come crashing down Tada look at the porn in there and check this out. What a Bobby Dazzler fed inom it's an absolute cracker this one. Look at the uh, we got two four, 6, 8 nine platters in here. single sided, uh head.

so that'd be doing. you know, just over one. Uh, Meg per plate? Unbelievable. And if we get in there with the measuring tape, we're looking at 11 in or thereabouts, you're working the old money with these, uh, hard drives 11in platters in there.

Beautiful. So this is what a quar of a million bucks would buy you in. Super reliable storage technology in the late 70s, early 80s. and uh, if you compare and contrast that with, you may have noticed it sitting here.

A modern, well, modern. These came out in 19, uh, mid90s. so really only you know, a 10 15 years uh, difference kind of thing between this thing which is 10 megabytes to a couple hundred gig uh This was later on, but you know we're talking four orders of magnitude. Look at it.

Unbelievable. But if you break these things down, you'll find that they're still essentially working identically. Yeah, the encoding format and the densities and the data rates of all Uh changed I mean the data rates inside modern hard drives are absolutely incredible. The serial data rates in and out of the heads and all the physics with the magnetics is all uh changed, but there essentially the operation is still the same with we've got the platters um, coated with the magnetic material, We've got the Uh spindle, we've got the actuators, we've got the heads, we've got the Uh head.

there's probably a head preamplifier on there and uh, you know, and the decoding. Electronics There are going to essentially be identical to Modern hard drives. and look at the solid uh machined Shazis on these things. Absolutely incredible.

And if you check out inside the head unit itself fully o-ring uh, sealed of course. But you'll notice they also got air filters in there either side, so that air filter down in there would be uh filtering the Halon pressurized Halon gas which goes into this thing now on the bottom here. it looks like we're going to have our spindle motor down in here. That would be this uh, cover plate down in there.

If we take that off, we might be able to, uh, look at the spindle motor under there. it looks like a huge monster and we, this is almost certainly our Actuator motor down here now. I'm not actually sure how much Electronics we're going to find in this thing. I mean we'll have our Um amplifier, uh, head on the top here on the Uh actuator arm itself.

looks like these are just sort of looks like some sort of interconnect system. I'll try and get those out later and uh, flat? Flix uh ribbon cable coming over and um certainly doesn't have the processing in it like a modern hard drives due today, that's for sure. Here you go, that wasn't hard at all. Watch this just snap that open.

look at that. all the that customized connector solution that you know like you won't find you know solution like that off the shelf. It's just totally customized for this particular unit. No wonder they had to charging a quarter of a million bucks a pop.

They had to amortise all the R&D cost of this thing and it looks like all the data for our heads uh pops out along all these traces. There's a lot of traces down in there and it pops down into um looks like probably I don't know if there's any Electronics under that, but probably down to that main header connector we saw down there and these flat flexors here. They just pop off here and then going into these two traces down the bottom there, which probably go down to uh, the main interconnect connector down on the back there, presumably and check it out folks. I Found a genuine Hardware bug in this thing right inside the channel there maybe during servicing and down on the bottom of the unit.

Here you can see this custom plastic, a flat Flex connector sort of embedded in uh, some plastic like this that that big huge couple hundred pin bus connector uh joins onto. So that actually does. It looks like goes straight down to there and then straight onto this paneling down in here. There you go.

It goes straight down into there, straight into these connectors and then straight over into the Uh heads there. So um, yeah, this thing, you know it. It doesn't look like it contains any processing Electronics uh at all apart from the Um apart from the Uh Asic presumably that would be on the head driver in there, the head uh amplifier SL buffer. That'll be about it.

Well, check this out folks. look at that date code February 18th, 1991 So I don't know if it was manufactured in 91 or whether or not they retrofitted a new cable to this thing in 91. But there you go. That's fascinating that they're still manufacturing the if they were.

if it is 91, they're still manufacturing these 10 megab hard drives right up until that time. And it turns out this temperature strip on the back here which does actually uh, work. By the way, I've had it. uh, go up and down in temperature is just a peel off tape like that that they stick on it.

It's There's no mechanism at all inside that look at that. It's gone up to 28 now. so it claims 30. There we go, slightly going up 32 as I touch this thing, it goes up in temperature.

neat. And if we take the cover plate off the the spindle motor here, it looks like, uh, correct me if I'm wrong. but we have a nine pole 3phase induction motor because, uh, there seems to be three phases there. There we go.

We got three main uh windings. We've got black, red and white there with the big thick cables like that. there's a green earth wire presumably, and a couple of other signal wires as well. So there you go.

That's a bit of a beast. I'm not sure how much Mass it actually has to, uh, rotate and at what? uh, speed. What operational speed this thing would have worked at, but that's a pretty funky looking unit I Like it and once again, we seem to have that date code 9th week 91. So I think this sucker was actually manufactured in 1991.

but hey, IBM would have had uh, this, you know, big, you know, decade long or decades long service contracts for these things and they didn't want to rock the boat, they just wanted to replace them with exactly what they got. So looks like they was still manufacturing these in 1991. Go figure. But you know I guess if they you know did the contract and manufactured first.

Uh, designed and manufactured these back in the early ' 80s or late 70s. You know it's not much more than a decade uh, service life which where this kind of industry is not that uncommon at all. And on this interface board here you can clearly see what's uh, likely a positional sensor. probably some sort of uh Hall sensor or something like that.

So they've got one there, one there, and one there and I just love looking inside these platins. Look at that. Ah, it's a thing of beauty. Joy Forever You can see in here part of the Rubber seal as well, which actually goes all the way down the side, there, right down here and over and around that into a uh machined Groove in the shazzy like that.

So that seals this. uh you know the air of this section. uh cuz the filter is just in between here. so the filter the uh air comes in here and then has to go through the filter to get to the rest of it.

Now check out the really cool linear slides on here. Look, we've got them machined into these blocks here and you can see the rollers inside there. So obviously this um head which uh, likely contains like a uh, four or five heads on it is designed to slide out of this somehow. but uh, haven't quite figured it out yet.

I've taken some screws off here, but it's um, it's really quite a complex uh block. Overall, this whole head system. it really is quite amazing. So I'm still trying to figure out how to slide this damn thing out.

and if we take off this black cover here, there's actually a grub screw in the back of this which uh then goes onto this spring and pushes that in and you can see the linear slide in there moving back and forth now. I can't pull that out. but uh, what that does is that um adjusts the head here so you'll be able as I move that you'll be able to see the head, just move it tweaking back and forth like that. All right.

I Figured out how to get this whole module out and with hindsight, it was obvious you had to take out the Uh Actuator motor from the bottom first cuz that shaft was holding the whole thing in through that little hole down in there like that. So there it is there So once you get that out from the bottom, you can lift out carefully. You don't scratch the discs. I'm sure there's a better way to do it, but Tada We have entire head assembly now.

These things, of course, would be designed to be very serviceable. I Mean you aren't going to just, uh, throw out. You know if it fails, you're not going to throw out one of these huge, uh, machined, diecast, um, Shazis or anything like that. Massively expensive.

I Mean you know this thing costs a quarter of a million dollars. You're going to service the thing so everything is designed with servicing in mind. If the you know, if you need to replace the platters, you're going to replace the platters. If you need to replace the heads, you're going to replace those.

Any of the uh, you know, well, there's not much else in it. uh, that can fail really. cuz this is essentially just a uh, spindle motor with a platin, an actuator, and some heads. and uh, that's pretty much it.

It's uh, just raw data out. but yeah, these things. um, these are not today's consumer throwaway items and you can see why they've gone for this. uh Flex PCB sort of embedded in this plastic membrane.

here. it's to get uh, good, uh. ceiling. Around here you can see it all gunked up right around the bottom around there.

and that's you know, complete airtight seal. So that's how they, uh, penetrate this thing and also right around inside there as well. So that's how they, um, penetrate the main shazzy down here while keeping an airtight seal with you know how many you know, 32 heads or whatever having to go through and penetrate. Get all the data out of this thing.

So that's how they decide to do it. and it's a never really seen, um, anything like that before. It's a quite remarkable construction technique, and here's where all the Precision Engineering comes in with the head. Even though the tolerances on this hard drive huge compared to today's standard, you can see the heads, uh, are able to move very smoothly.

trust me, that is pornographically smooth. um, on those linear bearings in there. Absolutely beautiful. And we got a total of uh, 32 heads.

I Thought this was, um, single-sided I Was told it was a single-sided uh, platin. but it's not because if you get in here, you can see there is uh, 32 heads total. There's actually a head back here and there's a head up here. I'll show you these in more detail in a second, but you can see that that little Flex arm there and the one on the top the heads are a bit out of whack cuz they're designed to free float and I'll show you that closer in a sec.

But there you go. That one does the upper side of that top plate. This one does the underside of the top plate. So the top surface of the top plate is not uh used.

But we got 16 heads down there and we've got another 16 heads back here. So with hard drives, a lot of the access time is going to be taken up with the physical movement of the actual Uor arm back and forth like that, or swept across the disc. In modern hard drives, you've seen them, you know, sweep back and forth Really really quick. Well, this would do the same thing.

it would move in and out, in and out really very quickly. but it takes time to get to the position, settle down before it can read or write the data. So the the uh, less distance you have to move like that, the greater your capable your data rate is going to be. And if you got jeel heads, well you can write twice as much information while moving half the distance.

We have a look at these heads in a bit more detail. You can see the Armature there. There's really slight pressure, you can see the Spring Bar in there designed to just put the required amount of pressure onto the head. and in this example here you can see that the Uh platter would sit in between the two like that and then they would rest on the surface and you'll notice that they're really very compliant and designed to sit very flat on that surface with very minimal amount of pressure.

Can probably see one of the little wires on the back side there for the head. and when I said single wire, well, it's actually a jewel pair. Look at that you can see the red and the Green in there. Hopefully you can see the arm moving up and down and that's actually a twisted peir going over and solded onto the flat Flex membrane over there and very nicely clamped in there.

It's got some uh tubing over it so you don't actually, uh, short or pinch out the wires there. Really beautiful construction and these would all be uh, you know, hand assembled and somebody's tweaked it with their tongue at the right angle. Ah, beautiful. You might be able to see it a bit clearer there.

They've put some tape over the top of that just to, uh, anchor the Uh wires in place just to take the stress out of those before they're soldered because you don't want any, uh, flexion on that or any vibration, uh, ruining that solder joint there and getting fatigue on that so they're de-stressing that with some tape. There really is, um, beautiful fine construction technique. I Really like it. Imagine what today's modern hard drives are like? Don't even ask and if you have a closeup of the head there, you can see that.

If I can get the pointer in here, you can see that uh, the where the two wires were solded on to I've actually broken that one off and uh, that goes into a coil down in there and it looks like there's a second identical coil on this side, but it's not actually connected there. so if we flip it up like that, you can see. oh, look at that. We got an individual serial number on there individually serial numbered.

Isn't that sexy? I Love it. And uh, the back back side of course, is nothing, uh, special, but that would be a, um, rather obscure material. uh, Ferite head. Now you'll notice that the head here is not completely flat.

It contains these skids either side of it here. and there's two reasons for this. It um, raises the uh feri and head uh above the surface of the disc by a fixed amount. But the first reason is that it reduces the uh friction.

Of course, because the less surface area, the less friction you're going to have. But the second reason they do it is that it forms a little aerodynamic pocket inside there, which helps stabilize and level the head when it's flying over the surface. And that can be very important for repeatability. And that's why the head uh, floats on those little armatures you've seen in there.

because it's essentially a self-leveling device. It's not just in a fixed position, it just, you know, uh, floats just above the surface there under aerodynamic pressure. Really neat design. Now a lot of the early magnetic alloy materials used in these heads are things you've probably never heard of like Uh Molly denim perm, alloy, things like Sendust and Alol go figure.

but um, then they moved on to Uh, some more Morphus Ferromagnetic Alloys and pretty much Um Ferites dominate the industry these days for heads, even around this area so this era. So this is probably some form of Ferite material and these new Ferite materials are usually either like a Nickel, Zinc, or a Magnesium Zinc type Uh combination alloy. But they're certainly not just your regular Uh Ferites you'll find in your Uh inductors and stuff like that. these are pretty, you know, obscure Um materials.

uh, you know, alloy materials used for very specific properties and it all has to do with the Uh width and the density and the hardness and all sorts of things that you're trying to get in Modern hard drive the modern ones these days. H Who knows what they're doing doing? it's rocket science now. these heads have to have near zero Magneto Striction it's called. which basically Uh means that this thing can change shape based on the applied magnetic field very slightly.

But because this is a highly Precision engineered head even back then I mean the modern ones today order of magnitude more. uh, sensitive of course. but uh, even back then you have to be very careful that this thing when you're writing the Ones and zeros to it changing the magnetic field that it does not physically change shape and that can work uh, vice versa as well. So any strain on this thing can actually, uh, generate a magnetic field so they can be use it as a sensor in that respect.

So you don't want any of those type of effects in a magnetic recording head, so these materials will be chosen to have near Zero magnetostriction. Effect Now these heads actually have to perform three functions on these hardes because they've only got the one head. so they have to do both, read, write, and also erase as well. And uh, a basic, a very crude, uh, inductive.

uh. Ferite head like this will have a Ferite material with the Gap in there. The Gap is uh, the part that sits over the track and does the recording and we've got you know, a couple C of turns of coil in there and that generates a threedimensional. That's important, a three-dimensional magnetic field in here with primarily as much coming out the y direction.

Onto the platter because if the platter's you know this thing's flat against your platter like that, then you want it to go out there and you don't want much in the X Direction here because that's they're fringing effects. which then can you know if you track width is in there like that you don't want any any fringing effects to affect other tracks. I Mean they're not physical bumps like that. I'm You know, I'm just drawing the uh, the magnetic tracks in the platter.

Like that you don't want any fringing effects coming out the uh X Direction here and causing problems with adjacent tracks that you've just written. You know, if you're writing data to here, you don't want to accidentally write another bit into a track that you've just an adjacent track you've just written data to. So these are very complex and solving the three-dimensional magnetic field equations. There's their integrals over space and they, ah, there's all sorts of complex stuff that, uh, basically, you know you can't uh, solve them because um, they're finite distance.

They're not like an infinite space and stuff like that. Very difficult, very complex, uh. mathematical and three-dimensional field. uh, magnetic field solving stuff and you could do an entire PhD thesis on just magnetic heads.

Sure, many people have and the same thing goes with the Zed Direction here. I mean this platter might be. You know, spinning around in that direction. so you know you've got your track on your hard drive there, so your steeper motors come in here for your head and it's right into this track here.

and this disc is spinning in this direction. You need to write each bit and you don't want fringing effects in The Zed Direction either because that can interfere with the last bit you just wrote on that uh, you know, rotating magnetic disc and there's lots of complex interactions with the Uh. You know the width of the Gap and the distance between the Gap and the platter, and the type of Uh material on the platter. and the magnetic fields and all sorts of stuff whether or not the corals are laminated and oh man, you could analyze these until the cows come home.

Now, one of the issues with these Uh heads, especially across uh, these sort of distances is what's called thermal track shift and that basically Um means well. As it implies, there's a thermal shift When these things heat up, These heads can physically expand just minute amount, minute amounts, and then it changes. It affects the position of the head relative to where it's supposed to be on the track. So you know, as these things warm up, you get uh, expansion of these arms and that can, uh, cause issues with track alignment or track misalignment.

So uh, you can also get changes in ambient temperature causing the same thing and that can be a big deal even at these sort of densities. We'll take a quick peek inside the Actuator motor here and uh, let's have a look. There's the Uh model number for those playing along at home and let's pop this way. Got a bit of spring movement there there we go.

check that out. isn't that beautiful and there's our motor down there. We've got another couple of cogs in there and looks like we've got a Uh device you um, acting as a heat sink in there I'm not sure what that suck is doing at all, so it looks like we got a some sort of spring return uh, gear reduction mechanism here. The motor drives this reduction gear system which then winds up that spring and there's a lot of I mean I can't manually move that? there's a Hu huge amount of torque required to, uh, move that sucker.

It's a traditional linear actuator motor controlled by these two strips over here. D There you go. And what this is is this is a Uh lock mechanism to lock the heads. it.

It actually goes in here like this. so it comes in here and I can turn that and boom I can pull and lock those heads back into position like that. so that locks both sets of heads and once it's released, it's only like a half turn. like a quarter turn or something like that.

So it's you know. So that's why this thing has that spring return mechanism. It just I Guess if there's you know power fails or something, then it automatically bang locks the heads back into position like that. Ah, really obvious.

So what we've got is, we've got like a voice coil in here. It's like it very much like a speaker. Exactly how a speaker works. But instead of moving a car, we're using moving four actuator arms and they separate Banks like that of four arms so they can move independently with these two voice coils.

Let's check out the voice coil resistance here if we can get in there. Tada Your traditional 8 Ohms H Are you thinking what? I'm thinking absolutely. But of course, this sort of linear actuator is not going to have the same sort of bandwidth as a traditional loudspeaker purely because we've got a lot more mass in this actuator arm uh, mechanism here than you do in like a paper cone on your traditional loudspeaker. So this thing's probably only going to have a bandwidth of, you know, maybe a KZ or two at most.

just enough to get the access time required for the head, so we can just easily drive our linear actuator with our function generator here. Now put in a sine wave at 10 Hertz and Taada, There it goes. works just just like a loudspeaker. If I take it right down to 1 V for example, we're getting tiny little bit of movement there if you can see that.

and if I up that 5 Vol 10 volts maximum of 20 volts on this function gen. There we go and of course we can adjust the frequency that's 10 HZ at the moment. So let me, uh, adjust that down one Hertz Boom boom boom boom boom boom boom boom Fantastic. And if we do a one Herz triangle wave there, you can see the uh, the more linear motion of it because of the ramp instead of the sine wave.

That's a 1 Herz sine wave and you can see the difference in the ramp. And if we do a 1 Herz Square wave, it's going to go bang bang bang bang bang bang. And although we're not going to be able to see higher frequencies, we'll certainly be I Want to hear them? Here we go. I'll put the mic up to it and you'll be able to hear that's 1 khz and then two.

he hey, three, 4, 5, 6, 78, 9, 10 KZ Woohoo! and you probably can't hear that now that's 15 khz. So there you go. Beauty think I'm finally able to get this bastard out of here. Ah, there we go.

Oh man. I've been struggling with that locking bar for ages Mongrel Precision Engineering My ass. Anyway, check it out. We can now.

should be able to lift out the entire module. Beauty So each one of these linear actuators weighs all almost 3.4 kilos on its own. That's for four actuator arms and 16 heads. Unbelievable man.

But these are all solid machined. um uh. linear guides on these things. Absolutely incredible Now I've taken the screws on this thing off, but I can't seem to get the Uh two halves open I think they've been pressed in there.

You can see the uh, You can see those uh press fit studs in there. It looks like they've been actually you know, hammered together and squeeze fitted in there. So I might have to try and pry it open. It's uh, cuz you can kind of just see the Uh where you can kind of see the coil in here somewhere.

there it is. down in there, you can see that we can actually see that coil inside there going over that Central bar. take a look at that. Nice.

So um I don't think we're actually going to be able to see anything else by taking this thing apart. um, and I can't I've got the hammer out and used a bit of percussive Maintenance but I cannot force this thing open so I might leave it as is, but there's nothing more interesting in there than just that coil going over the Uh Central magnet in there. that would be that would be basically it. And we've got those uh linear bearings.

Look at those. they just pornographic. really? Ever seen a speaker that good? I've taken off one of the heads here. it's still connected via the flat.

Flex Here, there's no way to avoid that. You can see a custom IBM uh can under there that no doubt contains the Uh head preamp and Uh is solded directly onto the flat Flex there, which of course goes over to the main connector that we've seen before. So uh, might see if I can pop that can over open and uh, see what we can find I mean we've got four pairs going into this thing from the four heads and then we've got the pairs going out and that just carries the raw uh head data back to the main header connector into as we saw right at the start of the video into uh, the uh, big rack connector system. So jeez, you know it's basically just a raw data output hard drive.

Now please, please excuse these uh heads I've got them falling off all over the place and missing. They're very delicate. but look at this. Here's this, uh, interlock bar in here.

here. It is right here and if I pull that back, you can see the heads pinched together like that. so that's part of that uh lockin protection. uh bar.

That was the pain in the ass to get out. It's just a motor to, uh, pull the heads back, lock them in place, and shut them down. These spring head mechanisms. They're really very delicate little beasts.

They would have been carefully designed to apply just the right amount of pressure, you know and they would have thoroughly tested them. Really tweaked and uh, highly engineered. part of hard drive design is just getting the correct pressure there on the heads. I Was able to pull the head module out of the flat Flex there and ah, look at that looks like it is fully potted.

Bummer. But of course that could just be the bottom of it so we should be able to get in there and uh, maybe hey, probably open this I sense a ceramic hybrid coming on. Well, there you go that was hardly worth popping off at all. Ah, just a bare dye mounted on a ceramic substrate there with a couple of like 0603 caps.

a Anyway, that would No Doubt a custom Uh IBM Asic does all the head Drive functionality record read: arras the whole works. Now as for these platters, these are very carefully uh machined aluminium discs and the material on there is like a Cobalt based alloy usually and that will be spotted on there in a vacuum deposition process and you can see that uh, some of it's all just spilled on the edges of the disc there. which doesn't matter a rat's ass really. it's all about the Uh Conformity and the thickness of the coating.

Now of course I was going to try and get these uh platters out, but I just cannot get my Uh shifter on the top of that, my shifting spanner on there to open it up. I'm going to need some uh, more heavyduty tools I don't have here in the lab. One's done up good and tight unfortunately. but there you have it.

Um, that's pretty much all there is to this. uh, classic IBM hard drive and uh, as I said before, if you do have more details on this particular Uh model, we would, uh, love to hear about it. So please, uh, leave it in the comments or uh, go to the Eev blog Forum which is where all the action is going to happen on the talk of this sucker. So the technology in this thing is, uh, pretty basic as far as modern hard drives go, but it is incredibly machined.

These linear actuators? Fantastic. Just love it. Brilliant stuff. and uh, the magnetic uh density on these platters.

Used the 11in platters in this thing is absolutely nothing compared to Modern hard drives. and as you saw, there's no controller in this thing at all. The controller would be in the uh rack uh hard drive system because all we've got are these little uh, preamp head preamps in there which we saw and that's basically it. It's just, uh, amplifying the signal and then driving it along right into the uh, back plane bus and well, that's going to be one hell of a controller when it's got to control all these hard drives with all that raw data coming in.

but uh, this thing's only 10 megabytes. not huge data rate. but anyway, I Hope you enjoyed it. That is the most expensive tear down to date.

It's worth a quarter of a million. Doar, do you believe it? But hey, we're talking about Banks here. Catch you next time and of course no tear Downs Complete without sacrificing some blood to the tear down gods.