Hard Disk Drives vs Solid State Drives

systems and what makes each one special. And there are a lot of different ways that computer scientists have created to store information, either temporarily or you know, permanently or semi permanently using computer systems. To go through all of them and to explain how all of them work would actually take a few episodes. A lot of them work in similar ways but with different manifestations. And also a lot of those methods are actually totally obsolete today, so

we're not gonna go over everything. Instead, we're going to have a quick refresher on ROM, RAM, cash memory, and then storage systems. ROM and RAM are both types of computer memory. The purpose of computer memory is to have a way to reference instructions quickly to run processes, and by that I mean for the CPU to be able

to get to the information it needs. Typically, we refer to memory as being a type of data storage that a CPU can access directly, as opposed to permanent storage, which must be retrieved before the CPU can access it. A processor needs two major things to carry out tasks. It needs a list of instructions also known as what to do, and then data that's the stuff you're performing

operations upon. So with an absurdly simple analogy, it would be like a teacher telling a student, Hey, I'm going to give you some numbers, and I want you to add those numbers together. So the student already knows the instructions, right, They know that they are to add any numbers that the teacher gives them. Then the teacher gives a list of numbers, which would be the data in our example, and the student would carry out the instructions adding them.

Computer processors do something similar, though at a speed and level of complexity that's a little harder for us to grasp. But without memory, the processor has nothing to draw upon to actually do anything. Wrong. Stands for read only memory, and as the name suggests, this is memory that the computer can reference, but it doesn't change it or add to it, at least not under normal circumstances. There's some extreme exceptions, but we're not really going to get into

them here. So you can think of this like messages that have been etched in stone, but you lack the ability or the tools to carve in anything into stone. So you can read these messages that already exist, but you can't change them in any way. Typically, read only memory contains basic instructions that a computer system needs in order for all of its components to work together and to boot up. So for a computer to actually be able to detect and interact with the various components the

physical hardware that make up the computer. That's a necessary part of ROM, and it really is just a basic set of instructions that allow everything else to happen, like going through the initial process of recognizing inputting output devices. Without those instructions, the computer wouldn't do anything meaningful. It would just be a bunch of pieces that don't actually work together. RAM or random access memory, is kind of

like short term memory for humans. This is where a computer can store information that's elevant to whatever the computer is doing at that very moment. So if you're running a program, a computer will load relevant data in RAM for quick reference. It's kind of like how I write episodes. I take a lot of notes and then I've got my notes to refer to when i need to, you know, reference something. Accessing RAM is fast generally speaking, though there

are some potential bottlenecks. I'll mention those late in this episode. But what does the random access part of RAM mean? It means that the processor can access the data on a RAM chip wherever that data might be physically stored on that chip, and that accessing any part of the memory should generally take the same amount of time regardless

of where the data is stored. In contrast, there are some types of storage that would require a computer to scan through all the data recorded from the beginning of the storage until hill it hits the relevant patch of information. It's kind of like the difference between using a chapter select on a DVD or Blu Ray or just fast forward scrubbing through a movie to get to a specific scene. If you have a DVD or Blue ray that has chapters, you can just jump right to the relevant section and

you access that specific part of the story instantly. Without chapters, then you have to go through the whole movie sequentially to get to the part you actually want. RAM is more like the chapter select approach. RAM has a limited capacity. Now this depends on the type of RAM you've got installing your PC or your computational device. Some machines, like a lot of PCs, are designed in such a way that you can upgrade RAM over time. You can add

to it and create greater RAM capacity. But even upgraded, there will be a limit as to how much data can exist in RAM at any given time. You can't just keep updating RAM forever. Motherboards won't accept that. Processors can't work with it, so there are actual limitations that are dependent upon outside factors. Even with upgraded RAM, there is a limit to how much data can exist in RAM all at a given time. You can't load every

single thing from storage into RAM. It wouldn't make sense for me to copy all of my sources word for word in my notes, right because then my notes aren't notes anymore. They are copies of the original sources, and I wouldn't really be able to refer to them very quickly. RAM is also temporary, by which I mean that the data that is inside RAM only sticks around for as long as the device is powered. Computer systems dump the information and RAM whenever the computer shuts down or restarts,

so effectively the memory gets white. RAM is thus a type of volatile memory that means it works as long as the power is going to the system. You need a non volu a toll form of memory, something that's a more persistent, permanent method to store data in larger volumes if you want to be able to access it in subsequent sessions. ROM is non volatile, but then again, it's also unchangeable, so that doesn't do you any good either.

You need something that you can actually update that is also non volatile if you want to be able to hold onto data between sessions. Before I move on to that, though, I should also mention cash memory c a c ch E memory. This allows processors to access specific, frequently referred to data at very fast speeds, faster than RAM. It has less capacity for storage than RAM does, but it can hold stuff that the processor is going to need to refer to a lot in order to complete whatever

the task at hand happens to be. RAM capacity tends to be in the gigabyte range these days, but CASH tends to be much lower, like in the megabyte range, and just for the purposes of clarity, A byte is a unit of information that's equal to eight bits, and a bit is a piece of binary information a zero or a one. A megabyte is essentially one million bytes, and a gigabyte is essentially one billion bytes. A terabyte

is essentially one trillion bytes. If you were to look at a computer motherboard, you would see the CPU or central processing unit, which is what executes the programs, and physically closest to the CPU would be the cash memory, which holds data that's going to be referenced frequently by the CPU. Next would be the RAM, So the CPU would check for information in cash memory first to see if it's there. If not, it would send a fetch request for information stored in RAM to see if it's there.

And if the data isn't there, then the CPU has to send out a request to fetch data from non volatile storage. Non Volatile memory is necessary if you want to save data for longer than the immediate present. The tradeoff is it takes a processor a little bit longer to access that data. So in my notes example, let's say that I'm doing this episode and there's something I wanted to talk about, but I didn't write it down

in my notes. I do happen to know, however, that it's in one of the large, dusty books that surround me at all times. I am cursed with them. So I would take a book aside, and then I would start searching through the book to find the relevant information. And this takes a bit longer than just glancing at my notes would. And that's kind of what it's like for a computer to reference information that's stored on a

hard drive or solid state drive. When I was growing up, my family's first real computer was an Apple to Eat, and that computer did not have a hard drive. Instead, you would save information onto five and a quarter inch floppy disc ets the computer had a disk drive. You would slide the floppy disk into the disk drive and then you could access whatever information was stored on it,

or you could save information to it. If the computer needed to reference something from the disk, everything would be pretty much put on hold while the computer searched the disks contents for the specific information, then pull it up loaded into RAM, and then the computer program could continue. This process is particularly noticeable if you're running something really process or intensive like computer game. More complicated games such as those that have like really nice graphics, take up

a lot of space. From a data perspective, the developers will typically design a game so that the computer running the game will load chunks of the game into its memory, but if you navigate to a new chunk, the computer has to reference the information in storage and then update everything, and that leads to the dreaded loading screen, and developers have found a lot of different ways to kind of

deal with this. A common one was to put in a loading screen whenever you would go through a door that represented a major change of environment, such as if you were to go from the outside world of the game and enter the inside world, like going into a castle. Between being outside and inside, you know, when you would hit that door and you'd say open, you'd get treated

to a loading screen. So part of what we're going to learn about today is why loading screens are even a thing and what type of storage results in different weight times. And let's start with hard disk drives a ka, the platter based drives. Alright, So back in the day, we used to store data on either floppy disks or hard disks. Although floppy disks are really a thing of the past at this point, unless you're using a truly

old computer system, like a legacy computer system. Hard disks actually predate floppy disks, and we didn't call them hard disks originally because there was no floppy disk to refer to. You wouldn't call one without the other, right, there can be no good without evil. Well, originally we called these fixed disks, or sometimes we even were to them as Winchesters. And no, it wasn't a pair of brothers who went around attacking supernatural bad guys. In this case, the term

Winchester actually came from IBM. It was IBM computer scientists who pioneered the design of the platter based hard drive back in the nineteen fifties, and the code name was Winchester. But then once floppy disks came along, folks would refer to fixed discs as hard disks. And then you had the differentiation. You had the floppy disks, which were external, then you would insert them into a drive and then remove them when you were done, and you had hard

disks which stayed inside the computer. So hard disks are disc shaped there around with a hub or or hole in the middle, and they are contained within a sealed container, typically made of something like aluminum. And the reason why is because aluminum is a material that is non magnetic under normal conditions. If you went to truly extreme conditions, you could magnetize aluminum, but it would be well outside

the conditions you would find someone's personal computer in. So old hard discs could only hold a few megabytes worth of data and they measured like twenty inches in diameter. They were huge, you know. The much later there would be closer to three and a half inches in diameter. So typically hard disk drives actually have stacks of discs. It's not just a single disc like a single platter, it's actually a stack of them, and each platter in that stack is separated by a small amount of space,

so there's actually free space between each stack. If you think of one, two, and three, you've got a little bit of space between each of those. And that's really important and I'll get into that in a second. But floppy disks are a disc of thin plastic that has a coding of magnetic material on top of it, and the plastic disc is inside an envelope or disket made of thicker plastic and there have been several sizes of

floppy discs over the years. There were eight inch discs, five and a quarter inch discs like my Apple to e had, and then three and a half inch diskts, which my IBM compatible computer used. The eight and the five and aquarre inch discs were pretty thin. They were made out of a thinner plastic material and that gave us the name floppy disc because they were flexible, though you were not supposed to bend them in any way that would possibly ruin everything. In fact, if you really

bent it, you had just destroyed that disk. Uh. This was a piece of information that would have been useful to a lot of people back in the early eighties when they weren't aware that floppy did not mean you

can fold it. But the terminology would become more confusing later on when three and a half inch discs, which are in a much thicker plastic case one that is not flexible, When those came around, it confused everything because those discs weren't floppy like the five and a quarter inch ones, So some folks would mistakenly refer to three and a half inch discs as hard disks, but they

were still a type of external storage. You would insert a floppy disk into a disk drive, you would read or write to that disk, and then you could inject the disc and replace it with another one. And that's how our old Apple to E worked. If you were to write a page of text, you would save that page to a floppy disk for later retrieval because the computer had no way to store information on it permanently.

Later on, c d s or compact discs would largely replace the need for floppy disks, particularly when computers began to include drives that could read or write to c d s. But by then we were also looking at computers that had internal storage in the form of a hard disk drive. And really the hard disk and floppy disk systems are fairly similar to each other, so rather than explain how each one works, I'll focus on hard disks so that we can contrast that with solid state

drives in a little bit. Before we get into any of that, however, let's take a quick break. The first thing to get into our heads is that hard disk drives and floppy drives for that matter, are electro mechanical systems, so they have moving parts and if you were able to see through a computer, you know, Superman style, and you were able to see it's hard drive in motion. You might think it bears some resemblance to how a turntable plays the tracks on a vinyl record, And there

is some similarity there, but only to a very superficial point. See, a vinyl record has physical grooves in it. The groove is a three dimensional groove with a little ridges and dips and edges, and the stylus or needle of the record player vibrates as it travels along this groove, and those vibrations passed to a piece of electric crystal or a tiny electromagnet, and that transforms the kinetic energy the energy get movement into electrical energy, and that electrical signal

then passes on to amplifiers that boost that signal. That then goes on to speakers and it plays out as the sound that's on the record. Hard disc doesn't have a physical groove in it. Instead, it's a platter made out of something like ceramic glass or an aluminum alloy, and it has a mirror like finish. In fact, it's highly reflective. The disc has ferromagnetic particles bonded to it.

These particles, if they are exposed to a magnetic field become magnetized themselves, and they will hold on to that magnetic property. So if you create a system where you give meaning to the specific magnetic orientation of domains of particles domains or sectors or regions of these particles on the platter, you can designate that as stuff like zeros

and ones. For example, you could say that a domain that is magnetized so it aligns in the north direction is a one, and a domain that's aligned in the south direction is a zero. And then by applying a precise magnetic fluctuation to the domains, you could arrange them into meaningful representations of information. So with a hard disk drive, you do in fact have a disk, or more likely several disks or platters in a stack, and there is a hole or hub in the center of these disks,

and those fit around a spindle. The spindle has a motor that can spend the disc super fast. I'll get into how fast in a second. Then you've got a mechanical arm and this has the little read right heads and those are transducers. These act kind of like the knee doll on a turntable, but there have their own special properties, and this arm can move from the inner edge of the disc to the outer edge in a fraction of a second. In fact, it would not be unusual to have one of these be able to move

between those two edges fifty times per second. The arm itself is split so that the right head, as in the w R I T E head, the head that writes data to the disc, fits on one side of the platter, and the read head that reads information off the disc can fit on the other side of the platter. So the platter will spend between these two heads and they will be separated from that platter by just a tiny, tiny,

tiny amount of space. This is one of those points where our vinyl record analogy really breaks down, because it would be like you would have a stylus or needle on either side of a record as it plays on the turntable, and that just doesn't happen. Now. Typically the arms motion controlled with electro magnets. Then you are likely dealing with a stack of discs, so you would also be working with a stack of read write heads mounted

on this arm. You would have one pair of read write head transducers for every disc on the stack, and the arms would be separated like timees on a fork, so they can fit between those spinning disks, and it gets pretty snug in those hard drives. So if you had three platters in your hard drive, you would have six read right heads right, one read and one right

head for each of the three platters. A transducer, by the way, is a type of electronic device that converts one form of energy into another form of energy, and there's a lot of stuff that falls into that category. It's a broad category. So a microphone has a transducer. It converts the kinetic energy from air pressure fluctuations a k a. Sound into electrical signals. A speaker does the

same thing, but in the opposite direction. It takes electrical signals and converts those into kinetic energy by driving the diaphragm of a speaker to create fluctuations and air pressure, and we experience that a sound. A digital thermometer converts thermal energy into electrical energy, and then that can be measured and displayed on a little screen. The transducers in a hard disk drives read right head convert electrical energy

into magnetic energy. The arm positions the read right head at a very specific point along the spinning platter, and those platters are spinning at like a hundred seventy miles per hour two d seventy two kilometers per hour. They could be spinning at a rate of thirty six hundred RPMs. Those are the old slow hard disk drives. If you can believe it, pms ten thousand revolutions per minute. It's

incredible how fast they spend. And the transducer on these read right heads applies a magnetic fluctuation to that spinning disk, aligning magnetic particles either in a north or south orientation to indicate those ones and zeros recording information in binary data. Now, to read data, a transducer works more or less in reverse.

The arm moves out to a certain distance from the edge of the disk as the disc spins up, and the moving magnetic particles traveling below the read right head induce an electrical signal to flow through the head, which then can be sent on to a processor. So instead of making a magnetic flux affect the platter, the actual magnetic field that is generated by the particles on the platter affect the transducer. It's a very elegant kind of solution. Now, The data on a hard disk falls into areas known

as sectors and tracks. You can think of a track as a concentric circle, sort of like an archery target. These circles get larger as you get to the outer edge. It also means that they travel at a different speed. The outer edge of a record travels at a faster speed than the inner edge of a record, which doesn't seem to make sense at first because you think it's

all rotating at the same rate. But you have to remember that outer edge represents a further distance, so the outer edge is going further in the same amount of time as the inner edge, which means it has to be traveling faster. So so sectors are like wedges within those concentric circles. If you think of the platter as like a pie, the sectors would be the slices of

pie along these concentric circles. Mm hmm pie. Tracks are numbered with zero being the closest to the outermost edge of the disc, and then counting upward from there until you get all the way to the inner part of the disc. Sectors can hold a set number of bites, like five twelve bites. That's not very many bites. At all, they have a limited capacity. So in addition, the computer typically groups certain sectors together into what are called clusters.

The computer has to keep track of which sectors in which tracks have free space in them before saving a file to the hard drive. So when you're looking at a file management system and you see you have limited space on a computer device that has hard disk drive, you know that that actually corresponds with actual available physical space on the platters themselves. Also, one way some machines

organized hard drive platters is in cylinders. So we've got our stack of hard drive platters right there, all one round top of the other, separated by a thin amount of space. If you were to look at one track, one concentric circle on the top platter, you could imagine that the corresponding concentric circle on platters two and three are grouped with that same circle on the top platter, And then you've got yourself a cylinder for um platter

one down to platter three. They'll remember, these platterers are not in contact with one another, so it's a virtual cylinder. Not all computer systems use this method for organizing information on a hard disc. However, ideally, files get stored on adjacent sectors within a cluster, or adjacent clusters or clusters that are vertically aligned within a cylinder. In other words, the group together kind of geographically. But as hard disk drive space fills up, that just might not be possible.

You might not have enough adjacent sectors to be able to do that, and then it becomes necessary for the drive to store sections of a file's data into different sectors on the hard disk itself. The system keeps track of where all these bits of the files are, but it does mean that the transducer has to move around a lot more to read all the relevant data stored on the hard drive in order to send that files information to the CPU, and that's something that can cause

a little tiny delay. I mentioned and that this is an incredibly precise technology, which is extra impressive considering the speeds we're talking about with regard to both the arms movement and the revolutions per minute of the platters. But the word precise, ironically doesn't give you an idea of what I'm talking about with modern hard disk drives. So again,

let's imagine the grooves on a vinyl record album. Those grooves are typically between point zero four millimeters and point zero eight millimeters wide, or between forty to eighty microns wide. The bands of information on a hard disc can measure less than one hundred nanometers in width. A nanometer is one billionth of a meter, a micron is just one millionth of a meter, and a human hair typically has a width of between eighty thousand to one hundred thousand nanometers.

So imagine that these bands of information are measuring less than a hundred meters wide. That is incredible. In fact, if you were to measure one inch in from the edge of a disk, you could fit around three hundred thousand tracts of information side by side in that space.

Based on that with we refer to the amount of data that a hard disc can store on its physical structure as aerial density, not aerial like doing tricks on the trapeze, aerial as an a R E A L part of area, and these days that that can be greater than a ter a bit per square inch, and a terra bit, like I said, as a trillion bits, that's a hundred twenty five billion bytes. By comparison, IBM S three fifty Raymack disc way back in nineteen fifty six could only hold two thousand bits per square inch.

The increase in aerial density over time has followed a path similar to what we see with semiconductors and with Boar's law. To make all this possible, numerous discoveries and advancements were acquired. Increasing aerial density meant not just shrinking down components, but also expanding our understanding of stuff like quantum effects and magnetism. It would take me an entire series of podcasts to go through the various parts and ideas and discoveries that all contributed to our ability to

store this much information on a hard disk drive. But one bit I do want to mention specifically, just because it's super cool. So you might know that one of the challenges of keeping up with Moore's law has to do with a quantum effect called tunneling. Well, in a

similar way, magnetic storage had its own physical limitation. Once you try to squeeze the magnetic domains or regions into smaller physical spaces, once you try to pack those zeros and ones in even more tightly, you encountered something called the super paramagnetic effect. Yeah, it's something that Mary Poppins

would pricing about. Super para magnetic anyway. The issue is that when it's packed into such a small space, the magnetization of individual domains could end up switching very easily, particularly if there was any heat applied to the area. So if your magnetization switches and your storage of information is dependent upon magnetization, that would mean some of your zeros would become ones, and some of your ones would become zeros, so your files would become corrupted and unusable.

But the solution to this problem was actually pretty straightforward. See. Up to that point, the magnetic direction of those little domains had been longitudinal with regard to the platter. That means the magnetic polls pointed along the same plane as the platter, and scientists decided to change this so that the magnetic fields were now perpendicular with respect to the platter. So you can think of the magnetic fields is pointing up and down from the platter surface, rather than say

forward or backward. This solved the superpara magnetic effect, and it meant that engineers could increase the aerial density of disks even further. Now, the fact that we're talking about a mechanical process means that whenever you want to write information to a disk, or you want to retrieve information

from a disk, that arm must move into place. The disc has to spin up, the arm has to go to each sector to pull up the relevant bits of data that make up that file, and this takes a little bit of time, and that explains part of the delay to get information from storage into the computer's random access memory where the CPU can make some use of it. Now,

it's not a huge amount of time. Typically, the seek time, that is the delay between a CPU requesting a file and when the first bite of data is sent from storage to memory typically falls in the ten to twenty millisecond range, so it's not like it's, you know, order out for a pizza because you just decided to open up a word document. However, the actual rate at which a hard drive can deliver data to the CPU is

a different story. This is called the data rate, and it tends to have a fairly wide range depending on the hard drive, topping out at around two megabytes per second. So if you're using a device with a hard drive like this, you've probably experienced some delays as a CPU requests data and then waits for it to be delivered. The bigger and more complex the file, the longer the weight tends to be, and because hard drives have moving components,

stuff can wear down over time. There are a few potential points of failure, from the mechanical arm with the transducers mounted on it, to the spinning motor that turns the disks, to the alignment of the bladders themselves. If you have a top that has a physical hard drive in it and you were to accidentally drop that laptop while it was working, there's a good chance that you could dislodge those platters and then you've got a ruined

hard drive. Also, if any dust gets into that hard disk drive, it can create read write errors or even be enough to cause the arm to collide with the hard disk and ruin everything. See these days, the read write heads might just only be a few nanometers away from the surface of the disk, so to us, if we were to look at it, it would seem like the two pieces are actually in contact with one another, because that that space between them is so small that

even visible light is too big to show it. The distance between them is about the distance of the width of a couple of bands of d N and A. It's tiny, so a single mote of dust would be like a gargantuan boulder by comparison, and it's really hard for me to get my mind wrapped around it, because once we start talking about this level of scale, I can kind of conceptualize it, but I can't visualize it now. That's one of the reasons that these hard disks are

sealed in aluminum cases. It's to protect the platters from dust and other contaminants. It's also why you should never open up a hard disk drive unless you're okay with the fact that it's never going to serve a useful purpose outside of perhaps being an instruction to others on how disk drives work or or showing people what it looks like, because the chances are it's never going to run again. This is also why stuff like clean rooms

need to exist. Clean rooms are facilities that use powerful filtration and h VAC systems, along with incredibly strict protocols to prevent the introduction of dust particles. Stuff like hard drives and semiconductor chips need to be produced in clean room facilities to avoid the possibility of even just one

moat of dust getting in there and ruining everything. Hard disk drives tend to be fairly heavy and they require a decent amount of power to operate, but they also are cheap and they tend to be pretty high capacity. Meaning we've advanced the science of designing hard drives to a point where you can store an enormous amount of

information on a physical hard drive. But now it's time for us to turn our attention to the alternative long term storage solution, that of the solid state drive or s s D. And when we come back, I'll tell you all about it. But first let's take another quick break with solid state drives. Were no longer talking about mechanical systems. There are no moving parts. We're also no longer talking about magnetic media, so we're not saving data by magnetizing small areas on a chip or anything like that.

It's a form of nonvolatile memory, so the data does stick around even if the computer or device is powered off. The secret sauce in this case is that an s s D follows into the storage medium of semiconductor chips. Ss D chips share some similarities with other chips that are on your computer. For example, remember when I was talking about rom and Ram at the beginning of the episode well. A ROM chip is a microchip that is physically programmed to carry out specific sets of instructions, including

those necessary to boot up a computer. RAM chips are microchips that can temporarily hold information for quick reference by the CPU. The RAM and RAM chips are mounted on the motherboard that's the main circuit board for a computer, and SSD is not mounted on the motherboard like a physical hard drive. It lives separate from the motherboard. It

connects to the motherboard via cables. In fact, if you had a PC with a hard disk drive, you could open up your computer, you could disconnect your hard disk drive and you could install a solid state drive in its place without really changing anything else in the computer or The type of storage ss d s provide has a somewhat confusing name. It's called flash memory. I say it's confusing because we talked about random access memory or RAM. But that stuff is volatile, right, It goes away when

you power the device down, that information is gone. But flash memory and ss d s does not go away. The data stays put. So we've got two different kinds of memory here, one of which is actually storage. But don't blame me because I don't come up with the names. I'm just reporting them. Flash memory can come in a couple of different varieties, and the type we find an SSD drives is nan flash in A and D, but there's also nor flash. So what the heck is up

with those names and how are these two things different? Well, let's start with the names because they're based on a very foundational component of computer science. It harkens back to logic gates, which depend upon Boolean functions or Boolean algebra. This is all about binary variables, so it's a variable that can represent one of two values, like a zero or a one. Logic gates are the practical implementation of Boolean algebra. The gates determine what output is sent out

based on the incoming input. And let's use a simple example with the and gate. The and gate accepts two variables two variables as input, and the values for those inputs can be either a zero or a one. The and gate will output a one only if both inputs are also ones. So if you feed two one bits into the input of the hand gate, you get a one bit as the output. But if you were to feed in two zeros or a zero and a one,

or alternatively a one and a zero. We do differentiate between these, then the end gate would produce a zero as its output. So it's a set of rules. It says, if I get two ones, I give you a one. If I get anything else, I give you a zero. By contrast, and or gate produces a one, also known as a high output if at least one input is also a one. So the or gate will send out a one if the inputs are one in zero, zero and one or one in one, and it only produces

a zero if the inputs are both zero. So this case, you give me two zeros, I give you a zero. You give me any other combination, I give you a one. Logic gates are a way to build out complex responses to inputs. They are the instructions that tell the computer what outcome to produce given a specific input. So let's talk specifically about nand and nor. These are sort of the bizarro versions of the and A or gates. A nand gate produces a one output with every pair of

inputs except for one one. So in other words, if you give me a zero, zero, a zero one, or a one zero, I will give you a one output. If you were to give me one one, I would give you a zero output. A nore gate will only produce a one output if both inputs are zero. So you give me a zero one, a one zero, or a one one. I give you a big fat zero. You give me a zero zero. Hey, it's your lucky day.

I give you a one. Now. I've done an episode on logic gates many years ago to explain how why these are important, how they work in the realm of computer science, and what this actually all means, and it may be time for me to revisit that and to kind of give it a deeper treatment, because it really gives you an appreciation of the logical design that you have to create so that computers will do the stuff you want them to do. But for now, let's just put that aside and go back to nand versus NOR

flash memory. With both nand and NOR flash memory cards, you have transistors arranged in cells. They're laid out in a grid format, so you've got rows and you've got columns of transistors. In NOR flash cells, the grids are wired in parallel to one another, so you can think of them as being wired side by side. In nand flash cells. They're wired in series, which means you go from one to the next one and you wire them

all in order in a sequence. NAND cells have a greater density of transistors and they also use fewer wires than NOR cells. They can read and write data faster than NOR flash memory, so nand flash is great for the solid state drive, whereas NOR flash tends to be used for read only purposes, kind of like the wrong

chips on a motherboard. If you were to put an SSD and a hard disk drive mint for the exact same drive bay in a computer case next to each other, like if you were to take out a hard disk drive at an SSD drive and you put them side by side, they would look fairly similar there both be and metal you know, aluminum cases, and they would be the same size. But the SSD would have no mechanical parts and it would likely have a good amount of

unused space inside the case. The reason for that is for a convenience, the solid state drive needs to match the physical shape and size of the hard disk drive so that it can fit into the computer case properly, so it's really just there so it'll it'll be able to fit the model of the computer case, it's not

necessary for the ss D to actually function. The nand semiconductor chips in an ss D have transistors arranged in a grid, which means that the grid has columns and rows, and a chain of transistors conducting a current would represent the value of one. A chain that is not conducting current represents a zero. And at first, before you've stored any data on a solid state drive, you haven't. You

haven't saved anything to it. All the transistors would be carrying currents, so they would all be set to one. Saving data to the drive means that the solid state drive will actually start to block current to specific transistors to switch them from a one to a zero. Now, at each intersection of this column and row, you get a pair of transistors that form a cell. One of the two transistors is a control gate and the other

is a floating gate. To quote the house Stuff Works article on it quote, when current reaches the control gate, electrons flow onto the floating gate, creating a net positive charge that interrupts current flow. By applying precise voltages to the transistors, a unique pattern of ones and zeros emerges. End quote that article. By the way, was written by William Harris, not written by me. It's a great article. I highly recommend reading How solid state Drives Work if

you want to learn more. One big advantage of solid state drives over hard drives is that with no moving parts, the computer can access data from any part of the solid state drive with the same speed as any other part. There's no arm that needs to move into position, there's no platter that needs to spend, and this means that data can move from storage to RAM or into cash memory much faster than it would with a hard disk drive,

and it's fast enough to make a noticeable difference. And they also use less power than hard disk drives do, so that's another bonus. Now, a few years ago, there were some pretty big differences in storage capacity between hard drives and solid state drives. For a while, the hard drive had a really good head start, and so for a few years if you wanted a lot of storage, really the hard drive was the way to go. You

can get much higher copa a city hard drives. But today solid state drives are really caught up and it's possible to buy a solid state drive with the same storage capacity as a high capacity hard disk. Drive. However, solid state drives are much more expensive now. The cost fluctuates based on numerous market factors, but you're likely to spend double or more than what it would cost to get a hard disk drive that has the exact same

storage capacity, so they are much more expensive. Interestingly, solid state drives actually do wear out over time, despite the fact that they don't have moving parts. So the application of voltages on transistors, you know, changing the charge of those transistors that slowly wears out the transistors, and after a number of cycles a cycle being going from say a one to a zero back to a one. After a certain number of those, the cells will start to

wear out. Now, the typical number of cycles ranges in the thoul posens of cycles, and computers are really good at using up available storage space that hasn't been through a lot of cycles already, so typically you don't have to worry about the solid state drive giving out before some other component on your machine gives out. So in other words, you're far more likely to need to upgrade your computer due to your processor or something else other

than the solid state drive. It would be unusual for you to use a solid state drive so long that that cycle thing becomes a real issue. One interesting thing to remember is that there's always going to be bottlenecks for data transfer. You might speed up in one area, but you will start to find restrictions in other areas. The limitation might be in the amount of RAM you

have in your machine. The RAMS capacity is going to limit how much can be loaded into memory, which is why a lot of folks advocate for adding more RAM to a machine if you want to make it go faster. Of course, this only works if the machine actually has the capability to accept more RAM. You might have a device where you can't upgrade the RAM, or you might have a device where you've got as much RAM in it as the motherboard can support. But then there's also the bus, and a bus in a computer is a

connection between different components within the computer itself. Can actually also be external components that are attached to the computer. Bus is a very generic term, but you can think of the bus as a highway between two different components, and data travels down this highway to get from one to the other. So like the memory to the CPU, and a lot of devices placed the memory physically close

to the CPU to improve data transfer efficiency. It's kind of blows my mind to think about that, that the difference between you know, a centimeter can make a big difference in and transfer efficiency, and it's it's kind of crazy, but like a highway, a bus has a capacity limit to how much data can actually cross it in a of an instant, a bus will have a limit on

how many bits per second can move across it. So if you're trying to build a fast PC, you've got to take a lot of different things into consideration, including the processors, which might include not just a central processing unit, but maybe one or more graphics processing units, the RAM that supports those processors, the storage system you're going to be using, and more so making your computer go faster. There are a lot of different approaches you can take.

Adding more rams usually a pretty good one, but switching to a different kind of storage if you're using a hard disk drive, if you switch to a solid state drive, that can really help out a lot. It's also generally more reliable than a hard disk drive. Fewer failures happen with them. In general, they're always exceptions, and it's always, always, always a good idea to back up your data. Back it up, on an external drive or back it up

on a cloud service. Back it up somewhere just in case one of those catastrophic failures does happen, you'll still be able to get to the important information. So I hope that all of this was useful. It's really interesting stuff. Like I said, we can do a full episode on things like logic Gates further down the road. Logic is one of those things I really enjoy because it's all about just learning basic rules, and those rules are solid, Like the only thing that changes is what you're feeding

into those rules. But the rules themselves are dependable. And in the world I live in now, when I find something that's dependable, I hug it, I hug logic Gates. Guys. Okay, well that was weird. If you have any suggestions for future episodes of tech Stuff, whether it's a technology, a trend in tech, a person in tech, a company, anything like that, reach out to me. You can get in touch over on Twitter. The handle for the show is tech Stuff HSB you and I'll talk to you again

really soon. Y. Text Stuff is an I Heart Radio production. For more podcasts from I Heart Radio, visit the I Heart Radio app Apple podcasts, or wherever you listen to your favorite shows.