Join Mike Meyers for an in-depth discussion in this video Form factors, part of CompTIA A+ (220-901) Cert Prep: 2 Core Hardware.
- It's really cool that you can go to a computer store, buy a case, a motherboard, a power supply, a video card, all from different manufacturers and put them together, and they all actually fit. Well, that's important. Now, what I've got in front of me is a lot of very, very old stuff and a lot of very, very new stuff to explain the concept of what we call a form factor. Let's start with the new one, over here. Now, you understand that this case doesn't have anything to do with the manufacture of the power supply or the video card or the motherboard or anything.
Yet, I can buy a power supply and it fits in here beautifully. Do you see that? Every screw hole fits, it's absolutely perfect. The motherboard itself screws in. There are pre-set mount holes in the case itself that fit this motherboard and just about any other motherboard I would choose to buy. Also, if you take a look, we've got cards that are coming out. Now these cards, I can snap a card in and the card will screw in beautifully. Everything works absolutely perfectly. In order to pull something like this off, we have to make a standardized set of shapes, of forms, that define how big your power supply can be, where are the screw holes on your motherboard, how tall does the card have to be so it fits into a slot.
All of these, collectively, are known as a form factor. Now, form factors have been around for a long time. This is a great system, but it took us a while to get here. In order to appreciate the pain and suffering we went through, I need to go back in time a little bit. This little system unit you're staring at right here is a very famous one. This is the IBM 5170. This is actually one from my collection. I'm kind of proud of it. The IBM 5170, you may not have heard that term, but I'll bet you've heard another term.
This is an IBM AT computer. IBM came out with the AT as a successor to it's XT computer. When it came out, IBM designed it so that the cases, because IBM built the cases and the motherboards and the cards and everything, so IBM built this so that you had standardized holes for just about everything. Like right here is for a, this is a old style keyboard. But you can see we have slots and there's I/O ports that are coming in through the slots. Everything's fitting together beautifully. Clearly, we've got a big fan for a power supply.
And IBM, because they owned everything, they decided to call this form factor the AT form factor to go with this model of computer. The AT form factor was a very, very famous form factor. What made it really cool is that when IBM came out with this particular model of computer, they told other people and said to them, not directly, but in so many words, they said, "If you copy this, we won't sue you." And that's truly the big difference that separates Apple computers from what we now call IBM-compatible computers.
And that was because IBM said, back in the '80s, "We won't sue you." So, because of that, lots of people with names like Dell, and Gateway, and Hitachi, and Toshiba and all kinds of folks, started making computers that copied the AT form factor. Then, as a result, for almost the first 10 years of the computer world, the AT form factor was dominant. Well, AT was fine, but it had some issues. The way it ventilated, it didn't talk about where you had to put the CPU.
There were some issues with it that didn't make it an absolutely optimal form factor. One area that it fell really short in, was what we called low-profile computing. Instead of having a big, old system unit that was this high, the idea was that computers would shrink and we would start getting smaller and smaller computers that would pretty much just slide underneath your monitor and life was good. And for two decades, there were all kinds of attempts to try to supplant the AT form factor.
And we saw all kinds of stuff. I've got two also-rans up here, right now. One of these, oh they had names like NLX and LPX and all kinds of stuff. And what they would do is, well for one thing, you couldn't put full-size cards in them because they were lower. So one of the things they would do is they would put something like this in. And this is what we call a riser card. And the idea is that you would take a card like this and you would snap it into a particular slot and then you could put all your cards in sideways, and that way, you could keep your system lower.
Anyway, there was all kinds of attempts. And the bottom line is, is that AT triumphed over everybody because it worked and everybody knew the standards exactly, and everything was beautiful. It wasn't until the mid, arguably, late 1990s that Intel, using all its power that it could, came up with a new type of form factor called ATX. Once ATX came around, back in the 1990s, it took over the world by storm. It pushed AT, all the low profile ideas out of the way, and we've been living in an ATX world pretty much, every since.
The CompTIA A+ 220-901 exam is comprised of six key parts. The second, core hardware, is covered by this course. Instructor Mike Meyers explains the essential components and functions of motherboards, power supplies, and hard drives. He also shows you how to work with chipsets, troubleshoot electrical issues, implement RAID, and how to determine which hard drive technology to use depending on the circumstance.
Note: The six courses designed for the CompTIA A+ (220-901) exam preparation include core processing, core hardware, peripherals and building a PC, displays and printers, networking, and laptops and mobile devices.
We are a CompTIA Content Publishing Partner. As such, we are able to offer CompTIA exam vouchers at a 10% discount. For more information on how to obtain this discount, please download these PDF instructions.
- Working with motherboards, chipsets, and expansions
- Choosing a power supply
- Evaluating hard drive technologies
- Implementing RAID
- Troubleshooting issues