Hard Drive Questions?

[Tracker]

I'm a newbie when it comes to many computer parts, but i'm tryin to learn little by little.

What's the Difference between SATA and SCSI?
I've noticed that the SCSI Drives are packing RPM and are either 68 or 80 pins? What is that?
Which would be the better choice for gaming / all around work? (Not thinking about money or space)

I guess those are the only real questions I have about this subject for the moment. I tried looking this stuff up, but i kinda suck at that too, lol. Anyway, Thanks in advance.

[Fozzik]

Well, this could turn into something really long...but I'll try to hit just the highlights.

SATA - This stands for Serial Advanced Technology Attachment.

Advanced Technology, or "AT" was a name IBM gave to one of their very early home computers. Although most of the standard things inside a computer have changed a lot since the early 80's, some things, like the basic layout of the connectors for hard drives and optical drives, have stayed the same for a very long time. So, the name "ATA", or AT Attachment, has stuck around.

Serial ATA is a fairly new specification for the connection of devices, and is meant to replace what was generally just called ATA...which was a parallel interface. In order to keep the older and newer specifications separate, people have started calling the old one PATA (short for parallel ATA).

The difference between parallel and serial busses is exactly what it sounds like. Parallel transfers multiple bits at a time across the cables and bus, Serial sends bits one at a time.

The basic physical highlights of SATA are a small thin cable, a simple and small connector, and nice high available bandwidth of 150MB per second or higher. Most desktop hard drives cannot saturate a bus with that much bandwidth. Here's a picture of some SATA connectors and their cables...you'll notice they are much thinner and more simple than the old ribbon cables used for PATA.

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SCSI stands for Small Computer Systems Interface, which is a very old name that has stuck around and come to describe very different things than it did originally. SCSI (pronounced skuzzy) was designed as a way to connect lots of devices (Internal and external) to a computer. The main benefits that SCSI offered for external device attachment are now covered by USB (and much improved over the old external SCSI chains).

Internally, SCSI was used to connect multiple hard drives or other devices together on a single controller, and it has changed over time to become faster and faster. SCSI is now used almost exclusively for hard drives, and is generally used in environments where very high throughput is needed (like servers). The latest SCSI specifications have transfer rates of 320MB per second or higher, which is a ton of bandwidth.

Having lots of bandwidth is only useful if you can fill up the pipe. Although you could get several 15,000 RPM hard drives and plug them into a SCSI controller on your desktop computer, the fact is that it's unlikely you would be utilizing the extremely high speed they are capable of when doing normal desktop things like playing games. SCSI hard drives have become more and more specialized, and really are meant for the kind of accesses and usage that comes in a server.

Also, it would be very expensive. Now don't get me wrong, 15k RPM hard drives would be faster than the 7200 or 10k RPM drives you can get for SATA...but I think it's reaching the point of overkill. You would be spending a ton of extra money for what would most likely be a small performance boost.

The number of pins which you saw for the various SCSI specifications refer to the number of pins in the connector which attaches the drive to the cable, and the cable to the controller. There are a LOT of different SCSI specs, and you would have to make very sure to match the controller card, the cable, and the hard drive.

To sum up... SATA is a great new spec, and is most likely the way to go for a desktop computer. Although SCSI might be faster in some cases using the high-RPM drives, it really isn't designed for desktops anymore and would be much more expensive for very little benefit.

[Tracker]

Amazing info, I love reading about tech stuff (Nerd much? Jeeze)

So out of that, Would SCSI be better off for a really big server? Or would SATA do the trick in the end?

Another thing, Could you explain what this means please

Recoverable Read Errors 10 per 10 12th power it looks like bits read
Nonrecoverable Read Errors 1 per 10 15th power bits read

Thanks, :)

[Fozzik]

SATA would probably be very effective for small servers, the 2 to 8 processor type used for small office database or file serving. RAID controllers are now very common on just about all motherboards, nearly standard... but a more robust hardware RAID controller would probably be better for a server. I would say that the latest SATA spec would provide plenty of bandwidth in those type of applications...but for larger mainframes and the like, the higher RPM hard drives that are available for SCSI would probably make more sense.


Another thing, Could you explain what this means please?
Recoverable Read Errors 10 per 10 12th power it looks like bits read
Nonrecoverable Read Errors 1 per 10 15th power bits read

Thanks, :)

I have no idea. Looks like the report from a hard drive scanning utility, perhaps returning info on the bad sectors on a drive. All hard drives ship with bad sectors, which are blocked off when the drive is low-level formatted. This is one of the reasons why hard drives never have their full capacity... a 250GB drive will probably format to 210-220GB, and some of the reason is bad sectors or blocks on the platters.

If this report is from a drive that's been working for a while, it might be showing that the drive is getting ready to fail. Without more information, it's hard to say...but generally drives that begin "losing" areas of their platters are in a bad state and probably need to be replaced.

[Tracker]

Alright cool. For the most part of me asking these questions were because i need to think of a powerful server idea in the next few months. It's for a small buisness not for gaming, but in the next 2 years i did want to get some kind of server to host CS or one of those type is games.

Thanks Fozzik, I think that's all of the questions that I have for now. If you've got any more input on this, Please do tell :)

[Slide]

SATA would probably be very effective for small servers, the 2 to 8 processor type used for small office database or file serving. RAID controllers are now very common on just about all motherboards, nearly standard... but a more robust hardware RAID controller would probably be better for a server. I would say that the latest SATA spec would provide plenty of bandwidth in those type of applications...but for larger mainframes and the like, the higher RPM hard drives that are available for SCSI would probably make more sense.


We have a bunch of Xserve-Raid arrays at the office which AFAIK are based on SATA. We aren't really a typical IT environment in that we are fairly small, but people are HEAVY users of diskspace and disk IO (20 TB for ~50 users + whatever is local). The RAIDS are configured as RAID 5 and are easily capable of handling HD recording and streaming. Everyone is connected via Gigabit Ethernet and the drive latency has never been an issue - our bottlenecks have typically been network or server based.

[Slide]

Alright cool. For the most part of me asking these questions were because i need to think of a powerful server idea in the next few months. It's for a small buisness not for gaming, but in the next 2 years i did want to get some kind of server to host CS or one of those type is games.


If your not adverse to Apple, I've found OSX Server (Unlimited Client edition) / Xserve G5 / Xserve RAID to be a very cost effective server solution. The hardware costs are pretty comparable / slightly higher than a PC solution - but the lack of need for client access licenses is fantastic.

It has an LDAP directory, can run as a PDC or BDC, supports Windows and NFS filesharing, has web server and application server built in, can operate as a Print Server, has a database if you need it and can handle your mail requirements.

Basically it does most things a Linux box could do, with much less of the hassle.