RAID question

[MadMike]

First off, thanks to everyone who has helped with the questions I've had with the media center PC I'm working on. I'm hoping to order everything in the next few days.

I have one question about RAID, that I can't seem to find the answer to on the company's site. The card I'm ordering can handle up to 8 SATA drives, and I can see that they connect to the card using SATA cables that are included. But how do the drives get power? I don't see any kind of power connectors. Does the card take care of this, or is there some non-included part I need to get to hook them up to the power supply? :confused:

I'm trying to avoid any surprises, where I get my parts and can't do anything until the local computer shop opens the next day, since it closes at 7:00.

[Forgreatjustice]

your power supply has to have the SATA power cables.
not the card it self.

[Pedersen]

But how do the drives get power? I don't see any kind of power connectors. Does the card take care of this, or is there some non-included part I need to get to hook them up to the power supply? :confused:


Heya MadMike. First off, a quick picture from my favorite site for ordering computer gear: http://images10.newegg.com/NeweggImage/productimage/22-148-140-02.jpg

That should answer about the power, I hope (well, once you click on it, it will). Make sure the power supply for your computer has SATA power connectors. If not, you can buy adapters which will connect SATA to standard molex style power connectors. Here's a link from newegg for those as well:
http://www.newegg.com/Product/Product.aspx?Item=N82E16812123119

Hope that helps!

[MadMike]

I know about connecting a single drive to the power supply. I've done this before. But how do I go about connecting multiple drives (the card I'm looking to get can handle 8) to the power supply? Or do I need to use a different power supply?

This is the RAID card I'm looking at: http://www.newegg.com/product/product.asp?item=N82E16816115026

This is the power supply I've selected: http://www.newegg.com/product/product.asp?item=N82E16817182044

It says it has two SATA connectors. That's not nearly enough. How do I do this? Apologies in advance for asking stupid questions, I've never done a RAID before.

[Pedersen]

Don't worry about asking questions. It's failure to ask that makes us look like an idiot. You know, like I failed to ask for help with a program I'm working with for a few weeks, finally did, and got my resolution all within 60 seconds of asking. After wasting a few weeks.

Each drive needs its own power connector. If you're planning on hooking up 8 drives, you're hooking up a crapload of power requirements. The links were both to the raid card, so I don't know what power supply you were looking at, but I'd suggest making sure it's big. No, bigger than that. Power supply issues have been the bane of my existence lately. I've had computers fail to start, or behave unstably, due to insufficient power. I've had servers at work go down because we were trying to pull too much power at once.

Go big. I've seen thousand watt power supplies. You're probably going to want one of them if you're doing 8 drives. My home server is a dual core, dual chip Opteron, with 3 sata drives in a raid. I've got a 630 watt psu. And I don't think I'd put more in unless I could get a bigger psu.

[JustADude]

Each drive needs its own power connector. If you're planning on hooking up 8 drives, you're hooking up a crapload of power requirements. The links were both to the raid card, so I don't know what power supply you were looking at, but I'd suggest making sure it's big. No, bigger than that.

What he's saying is, basically, go to NewEgg's advanced search for power supplies and set it not to look for anything below about 1 Megawatt.

[MadMike]

Edited the previous post if you want to recheck it.

The card handles eight drives, but I'm starting out with just five for now.

It's a 500W. I glanced at a few 1000W ones, and they didn't have eight SATA connectors either. What do I do?

[JustADude]

I glanced at a few 1000W ones, and they didn't have eight SATA connectors either. What do I do?

Get the converters that Pedersen recommended. RELINKY (http://www.newegg.com/Product/Product.aspx?Item=N82E16812123119)

It turns one Molex connector into 2 SATA connectors, so you'll only need 3 or 4 of them to take care of things. Look for the best power supply, and don't worry about it's actual SATA count.

[MadMike]

OK, is the one I have selected OK, or should I go with a different one? If you could recommend one, that would be great. :)

[Pedersen]

What he's saying is, basically, go to NewEgg's advanced search for power supplies and set it not to look for anything below about 1 Megawatt.

Actually, I was thinking he might need a power supply in the 1.21 gigawatt range. Dunno if he has a broken town clock available to act as a relay, though... :)

And yeah, MadMike, 500W might be an issue for you, believe it or not. I found four drives and an Athlon 3GHz was not working so well on a 430W PSU. Without knowing the rest, you might get away with the 500W, but getting bigger will only help. To be totally serious, I don't think I'd go with less then 700W just to satisfy immediate needs. If you're planning on 8 in future, I'd get the 1000W, if for no other reason than to play it safe.

[MadMike]

OK, how's this one look? It's going to put the cost of the server up around 2 grand, but it's 1000W, and it has plenty of SATA connectors, so I shouldn't need any adapters.

http://www.newegg.com/Product/Product.aspx?Item=N82E16817189016

[Pedersen]

Let's put it this way: If I were building a system with 8 drives, and could afford it, I'd be buying that one. That's nice, and should hold you up for a very long time.

Heck, I've bookmarked it. When it comes time for me to build such a beast, I might wind up getting that PSU (assuming a newer model hasn't come out by then).

[MadMike]

OK, I've added that power supply to my wish list and removed the 500W one.

If you could take a look now, I'd appreciate it.

http://secure.newegg.com/NewVersion/wishlist/PublicWishDetail.asp?WishListNumber=4575345

[MadMike]

Damn it, I linked to the wrong PS.

This is the one I was looking at http://www.newegg.com/Product/Product.aspx?Item=N82E16817101023

One thing I like is it has 12 SATA connectors.

[Pedersen]

OK, I've added that power supply to my wish list and removed the 500W one.

If you could take a look now, I'd appreciate it.

http://secure.newegg.com/NewVersion/wishlist/PublicWishDetail.asp?WishListNumber=4575345

Very nice. Some small changes you might wish to make, but these are only ideas, and not nearly as important as the PSU.

First, the CPU is 64-bit. You might want to consider upgrading XP to XP64 bit. It adds $50 to the cost, but you get some added boost by having 64 bit. http://www.newegg.com/Product/Product.aspx?Item=N82E16832116378

Your memory setup is a 2 dimm set. If possible, you might wanna switch it down to 1 dimm. This way, if you go to upgrade memory later (which, with a server setup, is not necessarily likely, but as a Windows PC setup, is), you don't have to throw away a dimm.

You have a 160G drive and 5 750G drives. I'm assuming the 160G is meant for OS and programs, while the 750G is meant for data. It's a good setup. However, you could make things somewhat cheaper by dropping the 160G entirely. The 750G in RAID will provide you with 3 terabytes of space. Surely you could afford to give a few gigs over to the OS and programs? Oh, and I checked, that RAID card is bootable. You can do just that. Very likely, though, you will need a floppy drive, and a way to get the drivers for that raid card onto the floppy, so that XP can find it when you install. Small price to pay, and you get to drop $50 from the total.

Keyboard/Mouse: If this is going to be a media center type PC, go for a wireless keyboard and mouse. You're going to learn to hate having to walk over to your computer just to type on that keyboard, believe me. Personally, I do like Logitech, they make good stuff.

DVD-ROM Drive: Switch to this one: http://www.newegg.com/Product/Product.aspx?Item=N82E16827106073
It adds $20 to the cost, and you get burning capability. When you've got a recording and want to save it, you'll want the burner. The only reason not to do this (aside from monetary) is if you have a DVD burner elsewhere in the house.

I know, if you take all of my suggestions, you're going to add about $50 to the total, but I've got one other to make, and this one will really make you cringe.

Buy all eight drives. You're making a RAID array. You're going to want to have one large volume to store all your data on. Very likely, you do not have partition magic, or partition manager, or other such software, and were not planning on buying it in future. Under Windows, logical volumes (called Dynamic Disks) are horrible. I have never seen them work well. But I have had to undo them, and that can be extremely difficult.

If you get all eight drives all at once, you build your full RAID volume set all at once. You get the maximum space, and the least frustration down the road.

That last bit is the most optional of everything. The stuff above, I think is a really good idea, and will make you happy right away, without adding *too* much to the cost. The extra drives can not make you happy down the road, though they can frustrate you by their absence later.

The rest? Makes me wish I were building another system. I always forget how fun it is to make everything work :)

Oh, something else you could try, and this will cost you about $0.50, and an overnight download: http://www.ubuntu.com/ A variety of Linux. If you're not comfortable with the idea, don't do it. But if you're willing to experiment, it can be rather fun.

Hope any of this has helped!

[JustADude]

You have a 160G drive and 5 750G drives. I'm assuming the 160G is meant for OS and programs, while the 750G is meant for data. It's a good setup. However, you could make things somewhat cheaper by dropping the 160G entirely.

That was at my suggestion, Pedersen.

The logic there is to eliminate a potential I/O bottleneck with the system trying to compete with a streaming data file, as well as add maintaining integrity by placing files likely to be modified where they won't cause fragmentation to files that are, essentially, going to remain an unmodified archive.

[Pedersen]

That was at my suggestion, Pedersen. The logic there is to eliminate a potential I/O bottleneck with the system trying to compete with a streaming data file, as well as add maintaining integrity by placing files likely to be modified where they won't cause fragmentation to the Array drive.

Very good point. I've just gotten used to my system. I'm using MythTV on Linux, and have the whole thing on a RAID 0 array. No redundancy, no safeguards, but also I don't have issues like what you described there.

Windows, though, is a very different beast, and I forgot to take that into account with my suggestion. MadMike, JustADude is right: Keep the 160G drive. It's better for overall piece of mind with the rest.

[MadMike]

Re: the hard drives. Yes, the 160GB is for the OS. Someone -- I think it was Justadude -- suggested that I put the OS on a drive that's not part of the array, as write operations would slow it down.

I am building a media center PC, but this isn't it. This is just a server to store my vast DVD collection. I counted roughly 400 DVDs, and a recent sampling I did shows the average DVD to be about 6GB. I have a wireless keyboard and mouse for the actual media center PC, but I didn't see a need to have it for the server.

I don't see a need for a server to have a DVD burner, so I think I'll pass on that one. I don't have a burner for the media center either, but I do have one on the main computer, and I figure if I want to save any recordings, I can just use what I have.

I was looking at the manual for the RAID card, and you're right -- it does look like I'll need a floppy drive. Almost seems like a waste, but they don't cost much these days. Not like in the mid 80s when I paid over $300 for one.

I'll consider the extra drives, although I'm not sure if I'm going to go with it, since it's going to add quite a bit to the cost. I did have all eight at one time, but ended up changing it back. I figured when I need the additional drives, I can buy them then, and they'll most likely come down in price by then.

I would like to get into Linux at some point, but I'm feeling lost enough as it is. Not sure I want to pick this particular project to start on it.

[MadMike]

If you're curious, here's the Media Center PC: http://secure.newegg.com/NewVersion/wishlist/PublicWishDetail.asp?WishListNumber=5920326

[Pedersen]

Sorry about the delay, Mike, it's been hectic. Anyway, minor comments on the PC/Server setup, coming from my perspective with MythTV. Keep that in mind as you read this, as your experience under Windows may be significantly different.

First, I see a wireless card on the client. That leads me to believe that you are planning to stream the DVDs over wireless. Don't do that. Get a wired connection. Wireless is susceptible to outside interference, has lower bandwidth, and is altogether unsuited for streaming video. I've tried doing it myself, and for every hour of video, there was at least one noticeable pause (on the order of 1-2 seconds).

Switching to wired is more work in the home, to be sure, but the results are so much better.

Second, I see the WinTV401 card. I'm not familiar with it myself, as I use the WinTV PVR-250 (I think that's the model, anyway, it's been a while). The 250 has a hardware mpeg encoder, which means that the CPU does barely anything while the machine is recording to disk direct from cable. On average, the CPU will see about 5% usage for me. This compared to trying to have the CPU handle it on the fly, which would result in over 60% usage for me (at least).

What I'm getting at is this: Make sure that the WinTV401 has a hardware encoder on it. Much better results.

Finally, if you do both of these, consider putting the WinTV card on the server, and let recording happen there. You can stream TV shows around your house easily then.

Aside from that, I like the setup. Very nicely done. You've definitely done your research!

[MadMike]

I've already ordered the parts, and some of them have already arrived. I noticed your main concern was with the wireless, but I don't see a whole lot I can do about that. Ultimately, I want to build a media center for each of the TVs in the house (there are three.) Once I'm confident that everything's working out with the parts I've chosen for the first setup, I'm going to order the parts for the other two.

I've done a lot of testing with the computers I have now, and haven't seen any problems, except for the one time when the main PC went into screensaver mode and Diskkeeper started running. :doh: I even borrowed my son's laptop and accessed a movie wirelessly, even tried it with my wife's computer running the same movie at the same time, and it all looked good.

Not sure what I'm going to do if wireless doesn't work. Each TV is on a different floor of the house. The good thing is, the router is almost directly above both the TV and where I'm putting the server.

Thanks for your help, BTW. In appreciation, I fixed your title for you. :)

[MadMike]

I just opened the box and had a look at the parts that have arrived already. I just couldn't resist. I can't do much else, since no cases or processors have arrived.

I went with one of your earlier suggestions and bought all 8 750 GB drives instead of the five I had specified originally. They have them all in a shelf-shaped chunk of styrofoam, and damn! Eight drives together are kind of heavy!

[Pedersen]

I've already ordered the parts, and some of them have already arrived. I noticed your main concern was with the wireless, but I don't see a whole lot I can do about that. Ultimately, I want to build a media center for each of the TVs in the house (there are three.) Once I'm confident that everything's working out with the parts I've chosen for the first setup, I'm going to order the parts for the other two.

Ah, very cool. To explain some of what I was thinking/doing with my own, I built a networkable PVR system. One machine handles the recording, another (in fact, multiple others are possible, though I only use one) handles the playback. End result: Any place in the house I hook up to that server, I have all of the recordings available. This is why I put the capture card into the server.

As for running the wire, we just wired up our entire house. It really wasn't too bad. I did have to cut some holes into the sheetrock, but the sheetrock saw was all of $10. Definitely manageable. A little bit of paint, some drywall repair clips, and it's back to looking like nothing was there.

The hard part was using the flex bit to go between the floors. Still, if wireless works for you, then stick with it. No point in making more work when you don't need to, right? :) For me, I find I get too much interference, even though it's infrequent. I didn't wanna have any, so spent to make a wired network happen.

Thanks for your help, BTW. In appreciation, I fixed your title for you. :)

Hey, thanks! I always thought that putting "Admin" into the title was forbidden, so didn't try to fix it, and never bothered to figure out a new title. Very cool. Thanks :)

[MadMike]

As for running the wire, we just wired up our entire house. It really wasn't too bad. I did have to cut some holes into the sheetrock, but the sheetrock saw was all of $10. Definitely manageable. A little bit of paint, some drywall repair clips, and it's back to looking like nothing was there.


Oh, it's not that I don't know how to do it. I finished the basement almost singlehandedly, which included drywall, and I ran LAN cable from the router upstairs to the computer down here. If I end up having to also wire the server and the three media centers, that's going to require more ports than are on my router, and I like to leave one open for when I do repairs for people. I haven't seen too many routers with more than four ports.

Like you said, I'll see how it goes wirelessly, and go from there.

Hey, thanks! I always thought that putting "Admin" into the title was forbidden, so didn't try to fix it, and never bothered to figure out a new title. Very cool. Thanks :)

It's a security feature in the board software designed to prevent people from impersonating mods and admins. "Moderator", "Administrator", and "Admin" are censored from the title, as well as a few words that could potentially be security holes. I think "script" is one of them, but I'm too lazy to go look right now. ;)

However, mods and admins are exempt from the title censor, so I'm able to fix things like this. :)

[Pedersen]

I know what you mean. Gotta pick apart the boxes, see what came, and what can be done now. Been there, done that, man it's fun :)

And yeah, 8 drives weigh more than you would think. I should know, I just moved 30 of them for work today (and they weigh a lot more than you would think).

Anyway, have fun with it. Building your own is a blast, it really is. Some things that might happen to you on the way:

It's not likely to power up on the first try. Don't worry about it. Flip switches off, pull power cord, and reseat memory/cards/etc. You'd be surprised how often that fixes it.

You'd also be surprised how often that doesn't fix it. If, for some reason, it doesn't, remove all extra connections from the motherboard. This means you should only have these pieces plugged in:

CPU / Heatsink(Fan)
Power Supply
Power Button from case
Memory
Video card (if not using onboard video)
Monitor / Keyboard / Mouse


Nothing else allowed to be plugged in. Test to make sure it powers on. Power down, and add one component at a time. That will either fix the entire thing, or tell you which component is the problem.

Anyway, that's the tips for the day. I think I've got my IM contacts in my profile. Feel free to use them if you get stuck in the build process. I'll help out if I can.

[Pedersen]

If I end up having to also wire the server and the three media centers, that's going to require more ports than are on my router, and I like to leave one open for when I do repairs for people. I haven't seen too many routers with more than four ports.

Ah, I'm going to point something out to consider. The way that was phrased says (to me, anyway) that you either don't know this, or don't like the idea. On the off chance that it's something you don't know about, this could be of use: Get a switch. You'll use one port on your router, and gain as many new ports as your switch has. I've seen switches with hundreds of ports on them (they also cost tens of thousands of dollars, at the low end). I've seen switches with 5 ports. Your local Staples, Office Max, and Office Depot will all have low end switches for $40 or so which will give you an additional 8 ports you can use.

If you already knew about this, I'm sorry to have wasted time. If you didn't, well, hopefully it will help you somehow in future :)

However, mods and admins are exempt from the title censor, so I'm able to fix things like this. :)

Very cool. So, I'll state it here and now: If anybody is bothered by this, I'll change my title in a heartbeat. Let me know, either by PM or responding here. Otherwise, I'll keep it, and say thanks. It's nice to have that title, I admit :)

[MadMike]

I've done several builds and countless repairs in the past, so I have a pretty good idea of what to expect with that. That's not to say they've come out perfect every time. There's always some little thing.

Once, everything worked great, but the computer wasn't detecting the CD drives. Turns out I hooked them up to the power supply, but forgot to hook them up to the motherboard.

Another time, I fired it up and nothing happened. That time, everything was perfect, except that I forgot to connect the motherboard to the power supply.

The one I had now kept shutting off and crashing randomly, and I went nuts trying to figure out why. Turns out I forgot to remove the plastic cover to the processor. :doh: My son still hasn't let me live that one down.

And most recently, I built a computer for a friend and forgot to connect the floppy drive to the power supply.

Interesting idea about the switch. I really don't know much of anything about them, or even what the difference between a switch and a router is, but I took a quick peek at Newegg just now, and it doesn't look like they're that expensive. If the wireless thing doesn't work out, it's nice to see that there is a solution. I'd rather have a problem be a pain in the ass than a show-stopper. ;)

I checked my tracking numbers a minute ago, and everything is on it's way either to Harrisburg or Philadelphia. It looks like some or all of it will come tomorrow, or Friday at the latest. I'm going to be busy for awhile, I think.

[LostMyMind]

A switch is pretty much a very extreme simple router. No DNS, etc... It's been ages since I've worked with an switch. But I would see if you could find a switch that can "link" to your existing router thus making the current router have more ports. (Not all routers have a "link" port)

[Pedersen]

A switch is pretty much a very extreme simple router. No DNS, etc... It's been ages since I've worked with an switch. But I would see if you could find a switch that can "link" to your existing router thus making the current router have more ports. (Not all routers have a "link" port)

Okay, I'll simply say this: No, that's wrong. No simpler way of stating it. Every facet of it.

Now, to try and explain what a switch is, and why your router doesn't need a link port.

Every network has several layers. Believe it or not, there's actually an official description of these layers, but I'm not going to use that, because it needlessly complicates things.

First Layer: Physical. This is the wiring, the network cards, etc.

Second Layer: Hardest to define. Someone else who knows the official layer names will describe it better, but I'll call it signaling. Basically, these are the actual electrical signals that travel over the wires, and include some extremely basic information about the endpoints that are connected (such as switches, network cards, etc).

Third Layer: Protocol. TCP/IP is the most common, but IPX/SPX also is still used. Plenty of others that I don't know of.

Fourth Layer: Application. This is the level individual programs use, such as DNS, web browsers, ftp programs, etc.

Switches include everything up to layer 2, and thus cannot directly send your information to the internet. They need to speak to something that understands layer 3, and forward data there, to get data to reach the internet.

Routers include everything up to layer 3, thus allowing them to understand TCP/IP, and send your data to and from the internet.

This is a very simplified version of what goes on under the covers, so I'll post more of it if people ask, though I'll probably just go and find some good links for people to read instead. After all, large books have been written about this, and at least one company makes major money on these very topics (Cisco), and not just from hardware. You'd be surprised at how much they print, too.

Finally, it doesn't matter if your router has a link port or not. You can always attach a switch. In fact, you can attach a switch to a switch to a switch to a router, even if none of them have an uplink port.

You see, back at layer 1, there's actual standards for how the wires are to be made, and how the connectors are to be attached to those wires. Those connector types are known as TIA-568A and TIA-568B.

If you have a cable which has both connectors the (TIA-568A to TIA-568A or TIA-568B to TIA-568B), you have what's known as a straight through cable. If it is a very short cable (3 ft or less), it is a patch cable. This is what you use to connect your computer to a switch.

If you have a cable which has different connector types (TIA-568A to TIA-568B), you have what is known as a crossover cable. A crossover cable is what you use to connect a switch to a switch.

Many consumer grade switches have an auto-sensing capability that allows them to know what's on the other end, and act accordingly, so having straight through or cross over doesn't matter, but not all of them do.

Finally, your router that has 4 ports on it is actually two devices merged into one: A router and a switch. Those 4 ports are actually a switch. End result: You can always connect a switch to a router. In fact, there is no limit to how many you can daisy chain to make your connection work. You could string them from New York to California if you had enough money and switches. The main restriction is that the wires may be no more than 100m (about 330 feet).

Wow, that's more than I was intending to type. Sorry about the length of the post, but getting even a simplified (but still good) explanation can take time. Hope that it helps!

[LostMyMind]

Okay, I'll simply say this: No, that's wrong. No simpler way of stating it.
Not unless switches and gateways have change in the last 15+ years. I know all about the "new" way of confusing the matter. Switches are exactly that, switches. Which is what I said, you strip all of the "extra" out of a router, you got a switch. So my statement stands. Which you agreed at the end.
Finally, your router that has 4 ports on it is actually two devices merged into one: A router and a switch
With no "DHCP", no IP assignment. etc... you got a switch. A router more accurately is a switch and gateway. A router is just a switch with some bells and whistles (being the gateway). The router "link" port is where you connected the switch to the ISP network is simply a gateway port. Granted, a router has more sensitivity to a specific protocol (TCP/IP), due to the gateway.

Which is why.... Not all routers will work with other switches smoothly (with or without a cross-over cable). Some routers actually have push the gateway over into the switch (I dislike this), making it even more sensitive. I believe the fiber-optic routers that the local ISP is using does this. I hope I can figure a way around that (without doubling up gateways), when (or if) I switch to fiber.

I know because I've gone through a few switches that will only work with switches of the same kind (3com for one). You can use a cross-over cable, but that don't mean it will work. It might, but I wouldn't count on it. I've gone through enough 3com switches to know how fussy they can be.

As for your "2nd layer", I believe the normal standard communication protocol for ethernet is 802.x. Some switches even have a coaxial port (at least they did back then). But I don't know why you separate it from the 1st layer, you pretty much can't have the one without the other.

[Pedersen]

With no "DHCP", no IP assignment. etc... you got a switch. A router more accurately is a switch and gateway. A router is just a switch with some bells and whistles (being the gateway). The router "link" port is where you connected the switch to the ISP network is simply a gateway port. Granted, a router has more sensitivity to a specific protocol (TCP/IP), due to the gateway.

DHCP, DNS forwarding, port forwarding, and many of the other function that have been bundled into consumer "router" packages are extra items, and are, strictly speaking, parts of routers. Many routers can do it. Not all. To assume that all can is dangerous, at best.

I know because I've gone through a few switches that will only work with switches of the same kind (3com for one). You can use a cross-over cable, but that don't mean it will work. It might, but I wouldn't count on it. I've gone through enough 3com switches to know how fussy they can be.

Buying the same brand of equipment is always helpful to ensure things go as smoothly as possible. I know that from much hard won experience myself. I left that out of my original post, though, as I was more going for edification than I was trying to make recommendations.

As for your "2nd layer", I believe the normal standard communication protocol for ethernet is 802.x. Some switches even have a coaxial port (at least they did back then). But I don't know why you separate it from the 1st layer, you pretty much can't have the one without the other.

I was trying to remember the Data Link layer from the OSI stack, and just couldn't do it at that hour. I'm kind of surprised you didn't go for that opportunity to correct me, especially since I asked for that one.

For everybody else, A small change to the above:
Layer 2: The encoding layer. This is where all data is actually encoded onto the wire (or air, in the case of wireless), and given certain added attributes (such as a unique address for your network card), to aid in the send/receive of data meant for your computer.

So, switches still work at layer 2. Routers still work at layer 3. And they are very different beasts, which serve very different functions. Know which one you're buying, and why. And, where possible, buy from the same vendor, it makes life easier.