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One of my goals for this blog is to have regular installments of basic technical knowledge that I wish I had spelled out to me in one place instead of having to crawl Wikipedia.
I’m calling these nuggets of knowledge “Two Minute Tech Talks...” Because our attention spans can’t handle much more 😊
For the first post of this type, I’m going to start with a piece of knowledge that I am comfortable with: computer storage and memory.
I am not “certified” in storage, I don’t have any special qualifications that make me an expert in this field – which is why I’m writing this up. I simply always wished someone would explain this stuff to me in easy language.
What’s the difference between storage and memory?
First, let’s make the distinction between the two, because I’m darn tired of explaining to my mom that her laptop definitely does not have 256GB of memory.
I want you to picture yourself at your desk. You are on a conference call and need to take meeting notes. You have a nice notebook (for purposes of analogy, this one has gold-leaf pages) with some recent notes and a nice clean page to take new notes right next to you. That notepad is akin to your computer's memory. It is used for short term storage of information that the computer needs to use quickly.
In most computers today, there’s somewhere between 4 and 32GB of RAM installed on a really fast communication lane so the processor can access it rapidly.
Sidebar: Memory basics
RAM stands for "Random Access Memory" and currently, the latest revision of this memory is DDR4.
DDR is "Double Data Rate" and the "4" denotes "4th Generation." It's been a while since this was widely available to consumers (2014ish) and the previous generation, DDR3, was available in 2007 (these baddies stick around for a while). DDR5 is on its way for consumers in the near future. There's a few differences with each new generation, but the most important ones are that newer gens are FASTER and consume LESS POWER.
Memory comes in sticks known as DIMMs : Dual In-Line Memory Modules.
Sidebar: Storage basics
"Storage" is often referred to as a "hard drive" or a "disk". Nowadays, storage comes in a few different flavors.
Does it spin? It's an old-school "HDD" (Hard Disk Drive). These are inexpensive but prone to mechanical failure (read: not great for laptops because of how much we move them around) and (excruciatingly) SLOW.
On the plus side, you can get a really large capacity (multiple Terabytes) spinning disk drive to store stuff that you don't need to access very often, such as all that digital clutter from college I'll never clean out.
Today I found a 16TB option online for less than $400, and the 1TB option for about $40.
No moving parts? These we refer to as "SSDs" (Solid State Drives). They are much faster, but typically more expensive - even though the cost to make and buy these is coming down.
There are a few different types of media that are found in SSDs, and some of them are far more powerful (shameless plug for Intel(R) Optane(TM) here), but that's for another post.
Part of what makes the SSD faster is the type of physical media it is made of, but another part is the communication protocol it uses to talk to the computer.
SATA (Serial Advanced Technology Attachment): Until recently, almost all drives (HDD and used this interface. It was first introduced in 2000 and revised three times so the current version is SATA III, which itself has been revised four times... so the most recent is 3.4.
It's still pretty common to see SATA in use, and when coupled with a SSD, it's a pretty solid middle-ground for your storage needs.
You can get a 1TB SATA SSD for about $100 today.
NVMe over PCIe (Non-Volatile Memory Express over Peripheral Component Interconnect Express): NVMe was released in 2013 and it's designed specifically to work with those SSDs I mentioned. PCIe slots on the main computer board were originally designed for graphics cards, and they are incredibly fast.
If you're into gaming or content creation, you probably want one of these bad boys - note that they are generally more expensive than drives that use SATA.
A 1TB NVMe drive I found online for $140 today.
Anyway...
So now you’ve finished your meeting. You type up your notes, send them off to stakeholders, and close your golden notebook. If you’re anything like me, all that information you wrote down is cleared from your mind so you can focus on the next thing. This is kinda how computer memory works.
Still at your desk, someone asks you to show them your notes from middle school English class. The only copies you have are in a notebook… on a shelf… three thousand miles away. You must walk out of your office, get on a plane, grab the book, get back on the plane, go back to your office, scan your notes onto the computer, and BOOM 48 hours later you’ve shown them all your terrible haiku from 2001.
It seems outrageous because I’m trying to make a point.
That book you just flew to the other side of the country for is like your computer storage. It’s generally astronomically slower than the memory, but it can hold much more data. It’s also a lot slower because of the communication lane it sits on.
You need both for your computer to function correctly.
But, Rachel, why wouldn’t I just use all memory and no storage since it’s so fast and awesome?
Well, friend, there are a few reasons.
One, memory is traditionally VOLATILE.
This is the correct term to identify something that can’t store bits of data when it doesn’t have power. If you tried to store your middle school poetry on your memory, they’d be lost as soon as you shut down your computer for the day and we’d all be very sad. Storage, on the other hand, in NON-VOLATILE. It retains data when power is turned off. Rhyming couplets are safe for another power cycle.
Two, the processor can only handle so much memory.
There are size limits to how much the processor can work with at that fast pace. Your little notebook can only hold one page of info. That represents the memory limitation. With storage, we are much, much less constrained. You can get terabytes of storage on your computer in comparison to the couple of gigabytes of memory, like having ten thousand notebooks of sentence diagrams on that shelf three thousand miles away. (I think I just puked a little reliving that seventh grade class. Yikes.)
Three, memory is expensive.
VERY expensive. Maybe you thought I was being silly when I said you had a gold notepad, but again, I am silly for a reason. One can only afford so many gold notepads. Storage is traditionally much less expensive – like those piles of $0.10 70-page spiral notebooks your mom bought you back in the day.
If I've piqued your curiosity, you can visit the following links to learn more: