Speaker 1: Welcome to text Stuff, a production from my Heart Radio.
Speaker 1: Hey there, and welcome to tech Stuff. I'm your host,
Speaker 1: Jonathan Strickland. I'm an executive producer with I Heart Radio
Speaker 1: and I love all things tech and I recently had
Speaker 1: a couple of listeners right to me and ask if
Speaker 1: I could do an episode about solid state drives, which
Speaker 1: is a method of data storage. So today we're going
Speaker 1: to learn about different ways to store information with computer
Speaker 1: systems and what makes each one special. And there are
Speaker 1: a lot of different ways that computer scientists have created
Speaker 1: to store information, either temporarily or you know, permanently or
Speaker 1: semi permanently using computer systems. To go through all of
Speaker 1: them and to explain how all of them work would
Speaker 1: actually take a few episodes. A lot of them work
Speaker 1: in similar ways but with different manifestations. And also a
Speaker 1: lot of those methods are actually totally obsolete today, so
Speaker 1: we're not gonna go over everything. Instead, we're going to
Speaker 1: have a quick refresher on ROM, RAM, cash memory, and
Speaker 1: then storage systems. ROM and RAM are both types of
Speaker 1: computer memory. The purpose of computer memory is to have
Speaker 1: a way to reference instructions quickly to run processes, and
Speaker 1: by that I mean for the CPU to be able
Speaker 1: to get to the information it needs. Typically, we refer
Speaker 1: to memory as being a type of data storage that
Speaker 1: a CPU can access directly, as opposed to permanent storage,
Speaker 1: which must be retrieved before the CPU can access it.
Speaker 1: A processor needs two major things to carry out tasks.
Speaker 1: It needs a list of instructions also known as what
Speaker 1: to do, and then data that's the stuff you're performing
Speaker 1: operations upon. So with an absurdly simple analogy, it would
Speaker 1: be like a teacher telling a student, Hey, I'm going
Speaker 1: to give you some numbers, and I want you to
Speaker 1: add those numbers together. So the student already knows the instructions, right,
Speaker 1: They know that they are to add any numbers that
Speaker 1: the teacher gives them. Then the teacher gives a list
Speaker 1: of numbers, which would be the data in our example,
Speaker 1: and the student would carry out the instructions adding them.
Speaker 1: Computer processors do something similar, though at a speed and
Speaker 1: level of complexity that's a little harder for us to grasp.
Speaker 1: But without memory, the processor has nothing to draw upon
Speaker 1: to actually do anything. Wrong. Stands for read only memory,
Speaker 1: and as the name suggests, this is memory that the
Speaker 1: computer can reference, but it doesn't change it or add
Speaker 1: to it, at least not under normal circumstances. There's some
Speaker 1: extreme exceptions, but we're not really going to get into
Speaker 1: them here. So you can think of this like messages
Speaker 1: that have been etched in stone, but you lack the
Speaker 1: ability or the tools to carve in anything into stone.
Speaker 1: So you can read these messages that already exist, but
Speaker 1: you can't change them in any way. Typically, read only
Speaker 1: memory contains basic instructions that a computer system needs in
Speaker 1: order for all of its components to work together and
Speaker 1: to boot up. So for a computer to actually be
Speaker 1: able to detect and interact with the various components the
Speaker 1: physical hardware that make up the computer. That's a necessary
Speaker 1: part of ROM, and it really is just a basic
Speaker 1: set of instructions that allow everything else to happen, like
Speaker 1: going through the initial process of recognizing inputting output devices.
Speaker 1: Without those instructions, the computer wouldn't do anything meaningful. It
Speaker 1: would just be a bunch of pieces that don't actually
Speaker 1: work together. RAM or random access memory, is kind of
Speaker 1: like short term memory for humans. This is where a
Speaker 1: computer can store information that's elevant to whatever the computer
Speaker 1: is doing at that very moment. So if you're running
Speaker 1: a program, a computer will load relevant data in RAM
Speaker 1: for quick reference. It's kind of like how I write episodes.
Speaker 1: I take a lot of notes and then I've got
Speaker 1: my notes to refer to when i need to, you know,
Speaker 1: reference something. Accessing RAM is fast generally speaking, though there
Speaker 1: are some potential bottlenecks. I'll mention those late in this episode.
Speaker 1: But what does the random access part of RAM mean?
Speaker 1: It means that the processor can access the data on
Speaker 1: a RAM chip wherever that data might be physically stored
Speaker 1: on that chip, and that accessing any part of the
Speaker 1: memory should generally take the same amount of time regardless
Speaker 1: of where the data is stored. In contrast, there are
Speaker 1: some types of storage that would require a computer to
Speaker 1: scan through all the data recorded from the beginning of
Speaker 1: the storage until hill it hits the relevant patch of information.
Speaker 1: It's kind of like the difference between using a chapter
Speaker 1: select on a DVD or Blu Ray or just fast
Speaker 1: forward scrubbing through a movie to get to a specific scene.
Speaker 1: If you have a DVD or Blue ray that has chapters,
Speaker 1: you can just jump right to the relevant section and
Speaker 1: you access that specific part of the story instantly. Without chapters,
Speaker 1: then you have to go through the whole movie sequentially
Speaker 1: to get to the part you actually want. RAM is
Speaker 1: more like the chapter select approach. RAM has a limited capacity.
Speaker 1: Now this depends on the type of RAM you've got
Speaker 1: installing your PC or your computational device. Some machines, like
Speaker 1: a lot of PCs, are designed in such a way
Speaker 1: that you can upgrade RAM over time. You can add
Speaker 1: to it and create greater RAM capacity. But even upgraded,
Speaker 1: there will be a limit as to how much data
Speaker 1: can exist in RAM at any given time. You can't
Speaker 1: just keep updating RAM forever. Motherboards won't accept that. Processors
Speaker 1: can't work with it, so there are actual limitations that
Speaker 1: are dependent upon outside factors. Even with upgraded RAM, there
Speaker 1: is a limit to how much data can exist in
Speaker 1: RAM all at a given time. You can't load every
Speaker 1: single thing from storage into RAM. It wouldn't make sense
Speaker 1: for me to copy all of my sources word for
Speaker 1: word in my notes, right because then my notes aren't
Speaker 1: notes anymore. They are copies of the original sources, and
Speaker 1: I wouldn't really be able to refer to them very quickly.
Speaker 1: RAM is also temporary, by which I mean that the
Speaker 1: data that is inside RAM only sticks around for as
Speaker 1: long as the device is powered. Computer systems dump the
Speaker 1: information and RAM whenever the computer shuts down or restarts,
Speaker 1: so effectively the memory gets white. RAM is thus a
Speaker 1: type of volatile memory that means it works as long
Speaker 1: as the power is going to the system. You need
Speaker 1: a non volu a toll form of memory, something that's
Speaker 1: a more persistent, permanent method to store data in larger
Speaker 1: volumes if you want to be able to access it
Speaker 1: in subsequent sessions. ROM is non volatile, but then again,
Speaker 1: it's also unchangeable, so that doesn't do you any good either.
Speaker 1: You need something that you can actually update that is
Speaker 1: also non volatile if you want to be able to
Speaker 1: hold onto data between sessions. Before I move on to that, though,
Speaker 1: I should also mention cash memory c a c ch
Speaker 1: E memory. This allows processors to access specific, frequently referred
Speaker 1: to data at very fast speeds, faster than RAM. It
Speaker 1: has less capacity for storage than RAM does, but it
Speaker 1: can hold stuff that the processor is going to need
Speaker 1: to refer to a lot in order to complete whatever
Speaker 1: the task at hand happens to be. RAM capacity tends
Speaker 1: to be in the gigabyte range these days, but CASH
Speaker 1: tends to be much lower, like in the megabyte range,
Speaker 1: and just for the purposes of clarity, A byte is
Speaker 1: a unit of information that's equal to eight bits, and
Speaker 1: a bit is a piece of binary information a zero
Speaker 1: or a one. A megabyte is essentially one million bytes,
Speaker 1: and a gigabyte is essentially one billion bytes. A terabyte
Speaker 1: is essentially one trillion bytes. If you were to look
Speaker 1: at a computer motherboard, you would see the CPU or
Speaker 1: central processing unit, which is what executes the programs, and
Speaker 1: physically closest to the CPU would be the cash memory,
Speaker 1: which holds data that's going to be referenced frequently by
Speaker 1: the CPU. Next would be the RAM, So the CPU
Speaker 1: would check for information in cash memory first to see
Speaker 1: if it's there. If not, it would send a fetch
Speaker 1: request for information stored in RAM to see if it's there.
Speaker 1: And if the data isn't there, then the CPU has
Speaker 1: to send out a request to fetch data from non
Speaker 1: volatile storage. Non Volatile memory is necessary if you want
Speaker 1: to save data for longer than the immediate present. The
Speaker 1: tradeoff is it takes a processor a little bit longer
Speaker 1: to access that data. So in my notes example, let's
Speaker 1: say that I'm doing this episode and there's something I
Speaker 1: wanted to talk about, but I didn't write it down
Speaker 1: in my notes. I do happen to know, however, that
Speaker 1: it's in one of the large, dusty books that surround
Speaker 1: me at all times. I am cursed with them. So
Speaker 1: I would take a book aside, and then I would
Speaker 1: start searching through the book to find the relevant information.
Speaker 1: And this takes a bit longer than just glancing at
Speaker 1: my notes would. And that's kind of what it's like
Speaker 1: for a computer to reference information that's stored on a
Speaker 1: hard drive or solid state drive. When I was growing up,
Speaker 1: my family's first real computer was an Apple to Eat,
Speaker 1: and that computer did not have a hard drive. Instead,
Speaker 1: you would save information onto five and a quarter inch
Speaker 1: floppy disc ets the computer had a disk drive. You
Speaker 1: would slide the floppy disk into the disk drive and
Speaker 1: then you could access whatever information was stored on it,
Speaker 1: or you could save information to it. If the computer
Speaker 1: needed to reference something from the disk, everything would be
Speaker 1: pretty much put on hold while the computer searched the
Speaker 1: disks contents for the specific information, then pull it up
Speaker 1: loaded into RAM, and then the computer program could continue.
Speaker 1: This process is particularly noticeable if you're running something really
Speaker 1: process or intensive like computer game. More complicated games such
Speaker 1: as those that have like really nice graphics, take up
Speaker 1: a lot of space. From a data perspective, the developers
Speaker 1: will typically design a game so that the computer running
Speaker 1: the game will load chunks of the game into its memory,
Speaker 1: but if you navigate to a new chunk, the computer
Speaker 1: has to reference the information in storage and then update everything,
Speaker 1: and that leads to the dreaded loading screen, and developers
Speaker 1: have found a lot of different ways to kind of
Speaker 1: deal with this. A common one was to put in
Speaker 1: a loading screen whenever you would go through a door
Speaker 1: that represented a major change of environment, such as if
Speaker 1: you were to go from the outside world of the
Speaker 1: game and enter the inside world, like going into a castle.
Speaker 1: Between being outside and inside, you know, when you would
Speaker 1: hit that door and you'd say open, you'd get treated
Speaker 1: to a loading screen. So part of what we're going
Speaker 1: to learn about today is why loading screens are even
Speaker 1: a thing and what type of storage results in different
Speaker 1: weight times. And let's start with hard disk drives a ka,
Speaker 1: the platter based drives. Alright, So back in the day,
Speaker 1: we used to store data on either floppy disks or
Speaker 1: hard disks. Although floppy disks are really a thing of
Speaker 1: the past at this point, unless you're using a truly
Speaker 1: old computer system, like a legacy computer system. Hard disks
Speaker 1: actually predate floppy disks, and we didn't call them hard
Speaker 1: disks originally because there was no floppy disk to refer to.
Speaker 1: You wouldn't call one without the other, right, there can
Speaker 1: be no good without evil. Well, originally we called these
Speaker 1: fixed disks, or sometimes we even were to them as Winchesters.
Speaker 1: And no, it wasn't a pair of brothers who went
Speaker 1: around attacking supernatural bad guys. In this case, the term
Speaker 1: Winchester actually came from IBM. It was IBM computer scientists
Speaker 1: who pioneered the design of the platter based hard drive
Speaker 1: back in the nineteen fifties, and the code name was Winchester.
Speaker 1: But then once floppy disks came along, folks would refer
Speaker 1: to fixed discs as hard disks. And then you had
Speaker 1: the differentiation. You had the floppy disks, which were external,
Speaker 1: then you would insert them into a drive and then
Speaker 1: remove them when you were done, and you had hard
Speaker 1: disks which stayed inside the computer. So hard disks are
Speaker 1: disc shaped there around with a hub or or hole
Speaker 1: in the middle, and they are contained within a sealed container,
Speaker 1: typically made of something like aluminum. And the reason why
Speaker 1: is because aluminum is a material that is non magnetic
Speaker 1: under normal conditions. If you went to truly extreme conditions,
Speaker 1: you could magnetize aluminum, but it would be well outside
Speaker 1: the conditions you would find someone's personal computer in. So
Speaker 1: old hard discs could only hold a few megabytes worth
Speaker 1: of data and they measured like twenty inches in diameter.
Speaker 1: They were huge, you know. The much later there would
Speaker 1: be closer to three and a half inches in diameter.
Speaker 1: So typically hard disk drives actually have stacks of discs.
Speaker 1: It's not just a single disc like a single platter,
Speaker 1: it's actually a stack of them, and each platter in
Speaker 1: that stack is separated by a small amount of space,
Speaker 1: so there's actually free space between each stack. If you
Speaker 1: think of one, two, and three, you've got a little
Speaker 1: bit of space between each of those. And that's really
Speaker 1: important and I'll get into that in a second. But
Speaker 1: floppy disks are a disc of thin plastic that has
Speaker 1: a coding of magnetic material on top of it, and
Speaker 1: the plastic disc is inside an envelope or disket made
Speaker 1: of thicker plastic and there have been several sizes of
Speaker 1: floppy discs over the years. There were eight inch discs,
Speaker 1: five and a quarter inch discs like my Apple to
Speaker 1: e had, and then three and a half inch diskts,
Speaker 1: which my IBM compatible computer used. The eight and the
Speaker 1: five and aquarre inch discs were pretty thin. They were
Speaker 1: made out of a thinner plastic material and that gave
Speaker 1: us the name floppy disc because they were flexible, though
Speaker 1: you were not supposed to bend them in any way
Speaker 1: that would possibly ruin everything. In fact, if you really
Speaker 1: bent it, you had just destroyed that disk. Uh. This
Speaker 1: was a piece of information that would have been useful
Speaker 1: to a lot of people back in the early eighties
Speaker 1: when they weren't aware that floppy did not mean you
Speaker 1: can fold it. But the terminology would become more confusing
Speaker 1: later on when three and a half inch discs, which
Speaker 1: are in a much thicker plastic case one that is
Speaker 1: not flexible, When those came around, it confused everything because
Speaker 1: those discs weren't floppy like the five and a quarter
Speaker 1: inch ones, So some folks would mistakenly refer to three
Speaker 1: and a half inch discs as hard disks, but they
Speaker 1: were still a type of external storage. You would insert
Speaker 1: a floppy disk into a disk drive, you would read
Speaker 1: or write to that disk, and then you could inject
Speaker 1: the disc and replace it with another one. And that's
Speaker 1: how our old Apple to E worked. If you were
Speaker 1: to write a page of text, you would save that
Speaker 1: page to a floppy disk for later retrieval because the
Speaker 1: computer had no way to store information on it permanently.
Speaker 1: Later on, c d s or compact discs would largely
Speaker 1: replace the need for floppy disks, particularly when computers began
Speaker 1: to include drives that could read or write to c
Speaker 1: d s. But by then we were also looking at
Speaker 1: computers that had internal storage in the form of a
Speaker 1: hard disk drive. And really the hard disk and floppy
Speaker 1: disk systems are fairly similar to each other, so rather
Speaker 1: than explain how each one works, I'll focus on hard
Speaker 1: disks so that we can contrast that with solid state
Speaker 1: drives in a little bit. Before we get into any
Speaker 1: of that, however, let's take a quick break. The first
Speaker 1: thing to get into our heads is that hard disk
Speaker 1: drives and floppy drives for that matter, are electro mechanical systems,
Speaker 1: so they have moving parts and if you were able
Speaker 1: to see through a computer, you know, Superman style, and
Speaker 1: you were able to see it's hard drive in motion.
Speaker 1: You might think it bears some resemblance to how a
Speaker 1: turntable plays the tracks on a vinyl record, And there
Speaker 1: is some similarity there, but only to a very superficial point. See,
Speaker 1: a vinyl record has physical grooves in it. The groove
Speaker 1: is a three dimensional groove with a little ridges and
Speaker 1: dips and edges, and the stylus or needle of the
Speaker 1: record player vibrates as it travels along this groove, and
Speaker 1: those vibrations passed to a piece of electric crystal or
Speaker 1: a tiny electromagnet, and that transforms the kinetic energy the
Speaker 1: energy get movement into electrical energy, and that electrical signal
Speaker 1: then passes on to amplifiers that boost that signal. That
Speaker 1: then goes on to speakers and it plays out as
Speaker 1: the sound that's on the record. Hard disc doesn't have
Speaker 1: a physical groove in it. Instead, it's a platter made
Speaker 1: out of something like ceramic glass or an aluminum alloy,
Speaker 1: and it has a mirror like finish. In fact, it's
Speaker 1: highly reflective. The disc has ferromagnetic particles bonded to it.
Speaker 1: These particles, if they are exposed to a magnetic field
Speaker 1: become magnetized themselves, and they will hold on to that
Speaker 1: magnetic property. So if you create a system where you
Speaker 1: give meaning to the specific magnetic orientation of domains of
Speaker 1: particles domains or sectors or regions of these particles on
Speaker 1: the platter, you can designate that as stuff like zeros
Speaker 1: and ones. For example, you could say that a domain
Speaker 1: that is magnetized so it aligns in the north direction
Speaker 1: is a one, and a domain that's aligned in the
Speaker 1: south direction is a zero. And then by applying a
Speaker 1: precise magnetic fluctuation to the domains, you could arrange them
Speaker 1: into meaningful representations of information. So with a hard disk drive,
Speaker 1: you do in fact have a disk, or more likely
Speaker 1: several disks or platters in a stack, and there is
Speaker 1: a hole or hub in the center of these disks,
Speaker 1: and those fit around a spindle. The spindle has a
Speaker 1: motor that can spend the disc super fast. I'll get
Speaker 1: into how fast in a second. Then you've got a
Speaker 1: mechanical arm and this has the little read right heads
Speaker 1: and those are transducers. These act kind of like the
Speaker 1: knee doll on a turntable, but there have their own
Speaker 1: special properties, and this arm can move from the inner
Speaker 1: edge of the disc to the outer edge in a
Speaker 1: fraction of a second. In fact, it would not be
Speaker 1: unusual to have one of these be able to move
Speaker 1: between those two edges fifty times per second. The arm
Speaker 1: itself is split so that the right head, as in
Speaker 1: the w R I T E head, the head that
Speaker 1: writes data to the disc, fits on one side of
Speaker 1: the platter, and the read head that reads information off
Speaker 1: the disc can fit on the other side of the platter.
Speaker 1: So the platter will spend between these two heads and
Speaker 1: they will be separated from that platter by just a tiny, tiny,
Speaker 1: tiny amount of space. This is one of those points
Speaker 1: where our vinyl record analogy really breaks down, because it
Speaker 1: would be like you would have a stylus or needle
Speaker 1: on either side of a record as it plays on
Speaker 1: the turntable, and that just doesn't happen. Now. Typically the
Speaker 1: arms motion controlled with electro magnets. Then you are likely
Speaker 1: dealing with a stack of discs, so you would also
Speaker 1: be working with a stack of read write heads mounted
Speaker 1: on this arm. You would have one pair of read
Speaker 1: write head transducers for every disc on the stack, and
Speaker 1: the arms would be separated like timees on a fork,
Speaker 1: so they can fit between those spinning disks, and it
Speaker 1: gets pretty snug in those hard drives. So if you
Speaker 1: had three platters in your hard drive, you would have
Speaker 1: six read right heads right, one read and one right
Speaker 1: head for each of the three platters. A transducer, by
Speaker 1: the way, is a type of electronic device that converts
Speaker 1: one form of energy into another form of energy, and
Speaker 1: there's a lot of stuff that falls into that category.
Speaker 1: It's a broad category. So a microphone has a transducer.
Speaker 1: It converts the kinetic energy from air pressure fluctuations a
Speaker 1: k a. Sound into electrical signals. A speaker does the
Speaker 1: same thing, but in the opposite direction. It takes electrical
Speaker 1: signals and converts those into kinetic energy by driving the
Speaker 1: diaphragm of a speaker to create fluctuations and air pressure,
Speaker 1: and we experience that a sound. A digital thermometer converts
Speaker 1: thermal energy into electrical energy, and then that can be
Speaker 1: measured and displayed on a little screen. The transducers in
Speaker 1: a hard disk drives read right head convert electrical energy
Speaker 1: into magnetic energy. The arm positions the read right head
Speaker 1: at a very specific point along the spinning platter, and
Speaker 1: those platters are spinning at like a hundred seventy miles
Speaker 1: per hour two d seventy two kilometers per hour. They
Speaker 1: could be spinning at a rate of thirty six hundred RPMs.
Speaker 1: Those are the old slow hard disk drives. If you
Speaker 1: can believe it, pms ten thousand revolutions per minute. It's
Speaker 1: incredible how fast they spend. And the transducer on these
Speaker 1: read right heads applies a magnetic fluctuation to that spinning disk,
Speaker 1: aligning magnetic particles either in a north or south orientation
Speaker 1: to indicate those ones and zeros recording information in binary data. Now,
Speaker 1: to read data, a transducer works more or less in reverse.
Speaker 1: The arm moves out to a certain distance from the
Speaker 1: edge of the disk as the disc spins up, and
Speaker 1: the moving magnetic particles traveling below the read right head
Speaker 1: induce an electrical signal to flow through the head, which
Speaker 1: then can be sent on to a processor. So instead
Speaker 1: of making a magnetic flux affect the platter, the actual
Speaker 1: magnetic field that is generated by the particles on the
Speaker 1: platter affect the transducer. It's a very elegant kind of solution. Now,
Speaker 1: The data on a hard disk falls into areas known
Speaker 1: as sectors and tracks. You can think of a track
Speaker 1: as a concentric circle, sort of like an archery target.
Speaker 1: These circles get larger as you get to the outer edge.
Speaker 1: It also means that they travel at a different speed.
Speaker 1: The outer edge of a record travels at a faster
Speaker 1: speed than the inner edge of a record, which doesn't
Speaker 1: seem to make sense at first because you think it's
Speaker 1: all rotating at the same rate. But you have to
Speaker 1: remember that outer edge represents a further distance, so the
Speaker 1: outer edge is going further in the same amount of
Speaker 1: time as the inner edge, which means it has to
Speaker 1: be traveling faster. So so sectors are like wedges within
Speaker 1: those concentric circles. If you think of the platter as
Speaker 1: like a pie, the sectors would be the slices of
Speaker 1: pie along these concentric circles. Mm hmm pie. Tracks are
Speaker 1: numbered with zero being the closest to the outermost edge
Speaker 1: of the disc, and then counting upward from there until
Speaker 1: you get all the way to the inner part of
Speaker 1: the disc. Sectors can hold a set number of bites,
Speaker 1: like five twelve bites. That's not very many bites. At all,
Speaker 1: they have a limited capacity. So in addition, the computer
Speaker 1: typically groups certain sectors together into what are called clusters.
Speaker 1: The computer has to keep track of which sectors in
Speaker 1: which tracks have free space in them before saving a
Speaker 1: file to the hard drive. So when you're looking at
Speaker 1: a file management system and you see you have limited
Speaker 1: space on a computer device that has hard disk drive,
Speaker 1: you know that that actually corresponds with actual available physical
Speaker 1: space on the platters themselves. Also, one way some machines
Speaker 1: organized hard drive platters is in cylinders. So we've got
Speaker 1: our stack of hard drive platters right there, all one
Speaker 1: round top of the other, separated by a thin amount
Speaker 1: of space. If you were to look at one track,
Speaker 1: one concentric circle on the top platter, you could imagine
Speaker 1: that the corresponding concentric circle on platters two and three
Speaker 1: are grouped with that same circle on the top platter,
Speaker 1: And then you've got yourself a cylinder for um platter
Speaker 1: one down to platter three. They'll remember, these platterers are
Speaker 1: not in contact with one another, so it's a virtual cylinder.
Speaker 1: Not all computer systems use this method for organizing information
Speaker 1: on a hard disc. However, ideally, files get stored on
Speaker 1: adjacent sectors within a cluster, or adjacent clusters or clusters
Speaker 1: that are vertically aligned within a cylinder. In other words,
Speaker 1: the group together kind of geographically. But as hard disk
Speaker 1: drive space fills up, that just might not be possible.
Speaker 1: You might not have enough adjacent sectors to be able
Speaker 1: to do that, and then it becomes necessary for the
Speaker 1: drive to store sections of a file's data into different
Speaker 1: sectors on the hard disk itself. The system keeps track
Speaker 1: of where all these bits of the files are, but
Speaker 1: it does mean that the transducer has to move around
Speaker 1: a lot more to read all the relevant data stored
Speaker 1: on the hard drive in order to send that files
Speaker 1: information to the CPU, and that's something that can cause
Speaker 1: a little tiny delay. I mentioned and that this is
Speaker 1: an incredibly precise technology, which is extra impressive considering the
Speaker 1: speeds we're talking about with regard to both the arms
Speaker 1: movement and the revolutions per minute of the platters. But
Speaker 1: the word precise, ironically doesn't give you an idea of
Speaker 1: what I'm talking about with modern hard disk drives. So again,
Speaker 1: let's imagine the grooves on a vinyl record album. Those
Speaker 1: grooves are typically between point zero four millimeters and point
Speaker 1: zero eight millimeters wide, or between forty to eighty microns wide.
Speaker 1: The bands of information on a hard disc can measure
Speaker 1: less than one hundred nanometers in width. A nanometer is
Speaker 1: one billionth of a meter, a micron is just one
Speaker 1: millionth of a meter, and a human hair typically has
Speaker 1: a width of between eighty thousand to one hundred thousand nanometers.
Speaker 1: So imagine that these bands of information are measuring less
Speaker 1: than a hundred meters wide. That is incredible. In fact,
Speaker 1: if you were to measure one inch in from the
Speaker 1: edge of a disk, you could fit around three hundred
Speaker 1: thousand tracts of information side by side in that space.
Speaker 1: Based on that with we refer to the amount of
Speaker 1: data that a hard disc can store on its physical
Speaker 1: structure as aerial density, not aerial like doing tricks on
Speaker 1: the trapeze, aerial as an a R E A L
Speaker 1: part of area, and these days that that can be
Speaker 1: greater than a ter a bit per square inch, and
Speaker 1: a terra bit, like I said, as a trillion bits,
Speaker 1: that's a hundred twenty five billion bytes. By comparison, IBM
Speaker 1: S three fifty Raymack disc way back in nineteen fifty
Speaker 1: six could only hold two thousand bits per square inch.
Speaker 1: The increase in aerial density over time has followed a
Speaker 1: path similar to what we see with semiconductors and with
Speaker 1: Boar's law. To make all this possible, numerous discoveries and
Speaker 1: advancements were acquired. Increasing aerial density meant not just shrinking
Speaker 1: down components, but also expanding our understanding of stuff like
Speaker 1: quantum effects and magnetism. It would take me an entire
Speaker 1: series of podcasts to go through the various parts and
Speaker 1: ideas and discoveries that all contributed to our ability to
Speaker 1: store this much information on a hard disk drive. But
Speaker 1: one bit I do want to mention specifically, just because
Speaker 1: it's super cool. So you might know that one of
Speaker 1: the challenges of keeping up with Moore's law has to
Speaker 1: do with a quantum effect called tunneling. Well, in a
Speaker 1: similar way, magnetic storage had its own physical limitation. Once
Speaker 1: you try to squeeze the magnetic domains or regions into
Speaker 1: smaller physical spaces, once you try to pack those zeros
Speaker 1: and ones in even more tightly, you encountered something called
Speaker 1: the super paramagnetic effect. Yeah, it's something that Mary Poppins
Speaker 1: would pricing about. Super para magnetic anyway. The issue is
Speaker 1: that when it's packed into such a small space, the
Speaker 1: magnetization of individual domains could end up switching very easily,
Speaker 1: particularly if there was any heat applied to the area.
Speaker 1: So if your magnetization switches and your storage of information
Speaker 1: is dependent upon magnetization, that would mean some of your
Speaker 1: zeros would become ones, and some of your ones would
Speaker 1: become zeros, so your files would become corrupted and unusable.
Speaker 1: But the solution to this problem was actually pretty straightforward. See.
Speaker 1: Up to that point, the magnetic direction of those little
Speaker 1: domains had been longitudinal with regard to the platter. That
Speaker 1: means the magnetic polls pointed along the same plane as
Speaker 1: the platter, and scientists decided to change this so that
Speaker 1: the magnetic fields were now perpendicular with respect to the platter.
Speaker 1: So you can think of the magnetic fields is pointing
Speaker 1: up and down from the platter surface, rather than say
Speaker 1: forward or backward. This solved the superpara magnetic effect, and
Speaker 1: it meant that engineers could increase the aerial density of
Speaker 1: disks even further. Now, the fact that we're talking about
Speaker 1: a mechanical process means that whenever you want to write
Speaker 1: information to a disk, or you want to retrieve information
Speaker 1: from a disk, that arm must move into place. The
Speaker 1: disc has to spin up, the arm has to go
Speaker 1: to each sector to pull up the relevant bits of
Speaker 1: data that make up that file, and this takes a
Speaker 1: little bit of time, and that explains part of the
Speaker 1: delay to get information from storage into the computer's random
Speaker 1: access memory where the CPU can make some use of it. Now,
Speaker 1: it's not a huge amount of time. Typically, the seek time,
Speaker 1: that is the delay between a CPU requesting a file
Speaker 1: and when the first bite of data is sent from
Speaker 1: storage to memory typically falls in the ten to twenty
Speaker 1: millisecond range, so it's not like it's, you know, order
Speaker 1: out for a pizza because you just decided to open
Speaker 1: up a word document. However, the actual rate at which
Speaker 1: a hard drive can deliver data to the CPU is
Speaker 1: a different story. This is called the data rate, and
Speaker 1: it tends to have a fairly wide range depending on
Speaker 1: the hard drive, topping out at around two megabytes per second.
Speaker 1: So if you're using a device with a hard drive
Speaker 1: like this, you've probably experienced some delays as a CPU
Speaker 1: requests data and then waits for it to be delivered.
Speaker 1: The bigger and more complex the file, the longer the
Speaker 1: weight tends to be, and because hard drives have moving components,
Speaker 1: stuff can wear down over time. There are a few
Speaker 1: potential points of failure, from the mechanical arm with the
Speaker 1: transducers mounted on it, to the spinning motor that turns
Speaker 1: the disks, to the alignment of the bladders themselves. If
Speaker 1: you have a top that has a physical hard drive
Speaker 1: in it and you were to accidentally drop that laptop
Speaker 1: while it was working, there's a good chance that you
Speaker 1: could dislodge those platters and then you've got a ruined
Speaker 1: hard drive. Also, if any dust gets into that hard
Speaker 1: disk drive, it can create read write errors or even
Speaker 1: be enough to cause the arm to collide with the
Speaker 1: hard disk and ruin everything. See these days, the read
Speaker 1: write heads might just only be a few nanometers away
Speaker 1: from the surface of the disk, so to us, if
Speaker 1: we were to look at it, it would seem like
Speaker 1: the two pieces are actually in contact with one another,
Speaker 1: because that that space between them is so small that
Speaker 1: even visible light is too big to show it. The
Speaker 1: distance between them is about the distance of the width
Speaker 1: of a couple of bands of d N and A.
Speaker 1: It's tiny, so a single mote of dust would be
Speaker 1: like a gargantuan boulder by comparison, and it's really hard
Speaker 1: for me to get my mind wrapped around it, because
Speaker 1: once we start talking about this level of scale, I
Speaker 1: can kind of conceptualize it, but I can't visualize it now.
Speaker 1: That's one of the reasons that these hard disks are
Speaker 1: sealed in aluminum cases. It's to protect the platters from
Speaker 1: dust and other contaminants. It's also why you should never
Speaker 1: open up a hard disk drive unless you're okay with
Speaker 1: the fact that it's never going to serve a useful
Speaker 1: purpose outside of perhaps being an instruction to others on
Speaker 1: how disk drives work or or showing people what it
Speaker 1: looks like, because the chances are it's never going to
Speaker 1: run again. This is also why stuff like clean rooms
Speaker 1: need to exist. Clean rooms are facilities that use powerful
Speaker 1: filtration and h VAC systems, along with incredibly strict protocols
Speaker 1: to prevent the introduction of dust particles. Stuff like hard
Speaker 1: drives and semiconductor chips need to be produced in clean
Speaker 1: room facilities to avoid the possibility of even just one
Speaker 1: moat of dust getting in there and ruining everything. Hard
Speaker 1: disk drives tend to be fairly heavy and they require
Speaker 1: a decent amount of power to operate, but they also
Speaker 1: are cheap and they tend to be pretty high capacity.
Speaker 1: Meaning we've advanced the science of designing hard drives to
Speaker 1: a point where you can store an enormous amount of
Speaker 1: information on a physical hard drive. But now it's time
Speaker 1: for us to turn our attention to the alternative long
Speaker 1: term storage solution, that of the solid state drive or
Speaker 1: s s D. And when we come back, I'll tell
Speaker 1: you all about it. But first let's take another quick
Speaker 1: break with solid state drives. Were no longer talking about
Speaker 1: mechanical systems. There are no moving parts. We're also no
Speaker 1: longer talking about magnetic media, so we're not saving data
Speaker 1: by magnetizing small areas on a chip or anything like that.
Speaker 1: It's a form of nonvolatile memory, so the data does
Speaker 1: stick around even if the computer or device is powered off.
Speaker 1: The secret sauce in this case is that an s
Speaker 1: s D follows into the storage medium of semiconductor chips.
Speaker 1: Ss D chips share some similarities with other chips that
Speaker 1: are on your computer. For example, remember when I was
Speaker 1: talking about rom and Ram at the beginning of the
Speaker 1: episode well. A ROM chip is a microchip that is
Speaker 1: physically programmed to carry out specific sets of instructions, including
Speaker 1: those necessary to boot up a computer. RAM chips are
Speaker 1: microchips that can temporarily hold information for quick reference by
Speaker 1: the CPU. The RAM and RAM chips are mounted on
Speaker 1: the motherboard that's the main circuit board for a computer,
Speaker 1: and SSD is not mounted on the motherboard like a
Speaker 1: physical hard drive. It lives separate from the motherboard. It
Speaker 1: connects to the motherboard via cables. In fact, if you
Speaker 1: had a PC with a hard disk drive, you could
Speaker 1: open up your computer, you could disconnect your hard disk
Speaker 1: drive and you could install a solid state drive in
Speaker 1: its place without really changing anything else in the computer
Speaker 1: or The type of storage ss d s provide has
Speaker 1: a somewhat confusing name. It's called flash memory. I say
Speaker 1: it's confusing because we talked about random access memory or RAM.
Speaker 1: But that stuff is volatile, right, It goes away when
Speaker 1: you power the device down, that information is gone. But
Speaker 1: flash memory and ss d s does not go away.
Speaker 1: The data stays put. So we've got two different kinds
Speaker 1: of memory here, one of which is actually storage. But
Speaker 1: don't blame me because I don't come up with the names.
Speaker 1: I'm just reporting them. Flash memory can come in a
Speaker 1: couple of different varieties, and the type we find an
Speaker 1: SSD drives is nan flash in A and D, but
Speaker 1: there's also nor flash. So what the heck is up
Speaker 1: with those names and how are these two things different? Well,
Speaker 1: let's start with the names because they're based on a
Speaker 1: very foundational component of computer science. It harkens back to
Speaker 1: logic gates, which depend upon Boolean functions or Boolean algebra.
Speaker 1: This is all about binary variables, so it's a variable
Speaker 1: that can represent one of two values, like a zero
Speaker 1: or a one. Logic gates are the practical implementation of
Speaker 1: Boolean algebra. The gates determine what output is sent out
Speaker 1: based on the incoming input. And let's use a simple
Speaker 1: example with the and gate. The and gate accepts two
Speaker 1: variables two variables as input, and the values for those
Speaker 1: inputs can be either a zero or a one. The
Speaker 1: and gate will output a one only if both inputs
Speaker 1: are also ones. So if you feed two one bits
Speaker 1: into the input of the hand gate, you get a
Speaker 1: one bit as the output. But if you were to
Speaker 1: feed in two zeros or a zero and a one,
Speaker 1: or alternatively a one and a zero. We do differentiate
Speaker 1: between these, then the end gate would produce a zero
Speaker 1: as its output. So it's a set of rules. It says,
Speaker 1: if I get two ones, I give you a one.
Speaker 1: If I get anything else, I give you a zero.
Speaker 1: By contrast, and or gate produces a one, also known
Speaker 1: as a high output if at least one input is
Speaker 1: also a one. So the or gate will send out
Speaker 1: a one if the inputs are one in zero, zero
Speaker 1: and one or one in one, and it only produces
Speaker 1: a zero if the inputs are both zero. So this case,
Speaker 1: you give me two zeros, I give you a zero.
Speaker 1: You give me any other combination, I give you a one.
Speaker 1: Logic gates are a way to build out complex responses
Speaker 1: to inputs. They are the instructions that tell the computer
Speaker 1: what outcome to produce given a specific input. So let's
Speaker 1: talk specifically about nand and nor. These are sort of
Speaker 1: the bizarro versions of the and A or gates. A
Speaker 1: nand gate produces a one output with every pair of
Speaker 1: inputs except for one one. So in other words, if
Speaker 1: you give me a zero, zero, a zero one, or
Speaker 1: a one zero, I will give you a one output.
Speaker 1: If you were to give me one one, I would
Speaker 1: give you a zero output. A nore gate will only
Speaker 1: produce a one output if both inputs are zero. So
Speaker 1: you give me a zero one, a one zero, or
Speaker 1: a one one. I give you a big fat zero.
Speaker 1: You give me a zero zero. Hey, it's your lucky day.
Speaker 1: I give you a one. Now. I've done an episode
Speaker 1: on logic gates many years ago to explain how why
Speaker 1: these are important, how they work in the realm of
Speaker 1: computer science, and what this actually all means, and it
Speaker 1: may be time for me to revisit that and to
Speaker 1: kind of give it a deeper treatment, because it really
Speaker 1: gives you an appreciation of the logical design that you
Speaker 1: have to create so that computers will do the stuff
Speaker 1: you want them to do. But for now, let's just
Speaker 1: put that aside and go back to nand versus NOR
Speaker 1: flash memory. With both nand and NOR flash memory cards,
Speaker 1: you have transistors arranged in cells. They're laid out in
Speaker 1: a grid format, so you've got rows and you've got
Speaker 1: columns of transistors. In NOR flash cells, the grids are
Speaker 1: wired in parallel to one another, so you can think
Speaker 1: of them as being wired side by side. In nand
Speaker 1: flash cells. They're wired in series, which means you go
Speaker 1: from one to the next one and you wire them
Speaker 1: all in order in a sequence. NAND cells have a
Speaker 1: greater density of transistors and they also use fewer wires
Speaker 1: than NOR cells. They can read and write data faster
Speaker 1: than NOR flash memory, so nand flash is great for
Speaker 1: the solid state drive, whereas NOR flash tends to be
Speaker 1: used for read only purposes, kind of like the wrong
Speaker 1: chips on a motherboard. If you were to put an
Speaker 1: SSD and a hard disk drive mint for the exact
Speaker 1: same drive bay in a computer case next to each other,
Speaker 1: like if you were to take out a hard disk
Speaker 1: drive at an SSD drive and you put them side
Speaker 1: by side, they would look fairly similar there both be
Speaker 1: and metal you know, aluminum cases, and they would be
Speaker 1: the same size. But the SSD would have no mechanical
Speaker 1: parts and it would likely have a good amount of
Speaker 1: unused space inside the case. The reason for that is
Speaker 1: for a convenience, the solid state drive needs to match
Speaker 1: the physical shape and size of the hard disk drive
Speaker 1: so that it can fit into the computer case properly,
Speaker 1: so it's really just there so it'll it'll be able
Speaker 1: to fit the model of the computer case, it's not
Speaker 1: necessary for the ss D to actually function. The nand
Speaker 1: semiconductor chips in an ss D have transistors arranged in
Speaker 1: a grid, which means that the grid has columns and rows,
Speaker 1: and a chain of transistors conducting a current would represent
Speaker 1: the value of one. A chain that is not conducting
Speaker 1: current represents a zero. And at first, before you've stored
Speaker 1: any data on a solid state drive, you haven't. You
Speaker 1: haven't saved anything to it. All the transistors would be
Speaker 1: carrying currents, so they would all be set to one.
Speaker 1: Saving data to the drive means that the solid state
Speaker 1: drive will actually start to block current to specific transistors
Speaker 1: to switch them from a one to a zero. Now,
Speaker 1: at each intersection of this column and row, you get
Speaker 1: a pair of transistors that form a cell. One of
Speaker 1: the two transistors is a control gate and the other
Speaker 1: is a floating gate. To quote the house Stuff Works
Speaker 1: article on it quote, when current reaches the control gate,
Speaker 1: electrons flow onto the floating gate, creating a net positive
Speaker 1: charge that interrupts current flow. By applying precise voltages to
Speaker 1: the transistors, a unique pattern of ones and zeros emerges.
Speaker 1: End quote that article. By the way, was written by
Speaker 1: William Harris, not written by me. It's a great article.
Speaker 1: I highly recommend reading How solid state Drives Work if
Speaker 1: you want to learn more. One big advantage of solid
Speaker 1: state drives over hard drives is that with no moving parts,
Speaker 1: the computer can access data from any part of the
Speaker 1: solid state drive with the same speed as any other part.
Speaker 1: There's no arm that needs to move into position, there's
Speaker 1: no platter that needs to spend, and this means that
Speaker 1: data can move from storage to RAM or into cash
Speaker 1: memory much faster than it would with a hard disk drive,
Speaker 1: and it's fast enough to make a noticeable difference. And
Speaker 1: they also use less power than hard disk drives do,
Speaker 1: so that's another bonus. Now, a few years ago, there
Speaker 1: were some pretty big differences in storage capacity between hard
Speaker 1: drives and solid state drives. For a while, the hard
Speaker 1: drive had a really good head start, and so for
Speaker 1: a few years if you wanted a lot of storage,
Speaker 1: really the hard drive was the way to go. You
Speaker 1: can get much higher copa a city hard drives. But
Speaker 1: today solid state drives are really caught up and it's
Speaker 1: possible to buy a solid state drive with the same
Speaker 1: storage capacity as a high capacity hard disk. Drive. However,
Speaker 1: solid state drives are much more expensive now. The cost
Speaker 1: fluctuates based on numerous market factors, but you're likely to
Speaker 1: spend double or more than what it would cost to
Speaker 1: get a hard disk drive that has the exact same
Speaker 1: storage capacity, so they are much more expensive. Interestingly, solid
Speaker 1: state drives actually do wear out over time, despite the
Speaker 1: fact that they don't have moving parts. So the application
Speaker 1: of voltages on transistors, you know, changing the charge of
Speaker 1: those transistors that slowly wears out the transistors, and after
Speaker 1: a number of cycles a cycle being going from say
Speaker 1: a one to a zero back to a one. After
Speaker 1: a certain number of those, the cells will start to
Speaker 1: wear out. Now, the typical number of cycles ranges in
Speaker 1: the thoul posens of cycles, and computers are really good
Speaker 1: at using up available storage space that hasn't been through
Speaker 1: a lot of cycles already, so typically you don't have
Speaker 1: to worry about the solid state drive giving out before
Speaker 1: some other component on your machine gives out. So in
Speaker 1: other words, you're far more likely to need to upgrade
Speaker 1: your computer due to your processor or something else other
Speaker 1: than the solid state drive. It would be unusual for
Speaker 1: you to use a solid state drive so long that
Speaker 1: that cycle thing becomes a real issue. One interesting thing
Speaker 1: to remember is that there's always going to be bottlenecks
Speaker 1: for data transfer. You might speed up in one area,
Speaker 1: but you will start to find restrictions in other areas.
Speaker 1: The limitation might be in the amount of RAM you
Speaker 1: have in your machine. The RAMS capacity is going to
Speaker 1: limit how much can be loaded into memory, which is
Speaker 1: why a lot of folks advocate for adding more RAM
Speaker 1: to a machine if you want to make it go faster.
Speaker 1: Of course, this only works if the machine actually has
Speaker 1: the capability to accept more RAM. You might have a
Speaker 1: device where you can't upgrade the RAM, or you might
Speaker 1: have a device where you've got as much RAM in
Speaker 1: it as the motherboard can support. But then there's also
Speaker 1: the bus, and a bus in a computer is a
Speaker 1: connection between different components within the computer itself. Can actually
Speaker 1: also be external components that are attached to the computer.
Speaker 1: Bus is a very generic term, but you can think
Speaker 1: of the bus as a highway between two different components,
Speaker 1: and data travels down this highway to get from one
Speaker 1: to the other. So like the memory to the CPU,
Speaker 1: and a lot of devices placed the memory physically close
Speaker 1: to the CPU to improve data transfer efficiency. It's kind
Speaker 1: of blows my mind to think about that, that the
Speaker 1: difference between you know, a centimeter can make a big
Speaker 1: difference in and transfer efficiency, and it's it's kind of crazy,
Speaker 1: but like a highway, a bus has a capacity limit
Speaker 1: to how much data can actually cross it in a
Speaker 1: of an instant, a bus will have a limit on
Speaker 1: how many bits per second can move across it. So
Speaker 1: if you're trying to build a fast PC, you've got
Speaker 1: to take a lot of different things into consideration, including
Speaker 1: the processors, which might include not just a central processing unit,
Speaker 1: but maybe one or more graphics processing units, the RAM
Speaker 1: that supports those processors, the storage system you're going to
Speaker 1: be using, and more so making your computer go faster.
Speaker 1: There are a lot of different approaches you can take.
Speaker 1: Adding more rams usually a pretty good one, but switching
Speaker 1: to a different kind of storage if you're using a
Speaker 1: hard disk drive, if you switch to a solid state drive,
Speaker 1: that can really help out a lot. It's also generally
Speaker 1: more reliable than a hard disk drive. Fewer failures happen
Speaker 1: with them. In general, they're always exceptions, and it's always, always,
Speaker 1: always a good idea to back up your data. Back
Speaker 1: it up, on an external drive or back it up
Speaker 1: on a cloud service. Back it up somewhere just in
Speaker 1: case one of those catastrophic failures does happen, you'll still
Speaker 1: be able to get to the important information. So I
Speaker 1: hope that all of this was useful. It's really interesting stuff.
Speaker 1: Like I said, we can do a full episode on
Speaker 1: things like logic Gates further down the road. Logic is
Speaker 1: one of those things I really enjoy because it's all
Speaker 1: about just learning basic rules, and those rules are solid,
Speaker 1: Like the only thing that changes is what you're feeding
Speaker 1: into those rules. But the rules themselves are dependable. And
Speaker 1: in the world I live in now, when I find
Speaker 1: something that's dependable, I hug it, I hug logic Gates. Guys. Okay,
Speaker 1: well that was weird. If you have any suggestions for
Speaker 1: future episodes of tech Stuff, whether it's a technology, a
Speaker 1: trend in tech, a person in tech, a company, anything
Speaker 1: like that, reach out to me. You can get in
Speaker 1: touch over on Twitter. The handle for the show is
Speaker 1: tech Stuff HSB you and I'll talk to you again
Speaker 1: really soon. Y. Text Stuff is an I Heart Radio production.
Speaker 1: For more podcasts from I Heart Radio, visit the I
Speaker 1: Heart Radio app Apple podcasts, or wherever you listen to
Speaker 1: your favorite shows.