Hard drive FAQ

[Bobthelost]

HD FAQ
Contents:

1. 
   Introduction
   
   Background
   • What?s the difference between IDE, PATA, ATA and SATA?
     What's the difference between SATA and SATA 2
     Things that might confuse you (NCQ and 300MB/s)
     Do I need to install any SATA drivers?
     What are TLER, TCQ, do i need to worry?
   RAID
   • Do I want to use RAID?
     RAID0
     RAID5
     Would 2 smaller drives be faster than one larger one?
     Are you saying that RAID has no use in gaming?
   SCSI
   • 
     Is SCSI the fastest system there is?
     Does this mean my 36gb 15k SCSI Drive is faster than a Raptor 150?
   Which drive should I buy?
   • 
     Speed freak
     Performance on a budget
     Audiophile
     Warranties

Introduction
This is an attempt to answer some of the frequently asked questions about hard drives, it's not going to be all encompasing. For better and more detailed information about all of this, as well as the numbers that i base my statements on please go to http://www.storagereview.com. If you see any errors then please either post or PM me, if you can also link to a source then so much the better. If you have anything that you think should be added the same goes.

If you want more information then go to storage review, especially for topics such as SCSI or really high end performance

What?s the difference between IDE, PATA, ATA, SATA?
The first three: IDE, PATA, ATA are all names for effectively the same thing. The old fashioned system of connecting Hard Drives (HDs) to your motherboard to transfer data, it?s the same cable type (normally thick and wide) as you use for 99% of optical drives. I?m not going into too much depth, but there is no real benefit to SATA drives over PATA at the moment, however all the new drives are being made to use SATA, so as time goes by you won?t be able to get current generation PATA drives.

Is SATA2 faster than SATA?
Not as such no. The fastest SATA drive there is, the raptor 150, uses the SATA 150Mb/ interface, not the SATA2. If you want to know which drive is faster then the bit to look at is NOT if it has SATA2. The only way to tell if a particular SATA drive is faster than a SATA2 drive is to check benchmarks. The best source of which is:
http://www.storagereview.com/comparison.html

What's the difference between SATA and SATA II
There isn't all that much difference, they use the same connectors, they use the same wires, most if not all motherboards will support either. There are some differences that kick in for professional setups but for the home user there is no inherrent difference. Some speed increases have been seen comparing SATA to SATA2 drives of the same range/design, but this is more likely due to a revised firmware and design than an inherrent improvement due to the interface.

Things that might confuse you:
300MB/s transfer rates!
Lies, damn lies and marketing, the SATA II standard allows faster data transfer(300MB/s instead of 150MB/s), but no single drive can supply more than 100MB/s if that, this only becomes useful when you have several drives on one connector, you won?t do this as a home user.
NCQ: Allows you to access data faster!
Here it?s half true, NCQ (Native Command Queuing) does improve disc performance, when in a server environment. For a single user it hurts performance, every single user test and benchmark backs this up, you don?t want NCQ on unless you?re running a server. But not to worry, NCQ is something you?d have to turn on in your driver settings, ignore it and be happy.

Do I need to install any SATA drivers?
No, it?s not necessary 99% of the time. Just plug the drive in and turn on your computer, in fact with SATA you don?t have to turn the PC off to install a new drive, (but I well wouldn?t if I were you) I have heard of motherboard makers (shuttle) who tell you to install RAID drivers for SATA drives, but it's rather uncommon.

What are TLER, TCQ
TLER or Time Limited Error Recovery is a feature some drives have for RAID arrays, unless you have a RAID setup you won't be able to use it, although i'm not sure if it'll cause any performance problems. TCQ is an earlier attempt at NCQ, and should be turned off for single user performance.

 

[Bobthelost]

RAID

Do I want to use RAID?
If you have to ask the answer is nearly always NO! RAID is a fantastic tool, but rarely is it a good idea, and if you have to have what RAID is explained to you then it's almost certainly not for you. RAID (Redundant Array of Inexpensive Discs) is a way of ganging together several hard drives so that it looks like one big drive. There are several ways to do it but the most common are RAID0 and RAID5. All of them need at least 2 drives, some of them need more. There are advantages and disadvantages to all of them. For a fuller understanding i recomend looking here: http:/www.google.com
http://www.storagereview.com/php/cms/cm...=news_content&id=970&start=26&range=10

RAID0 (2 drives minimum)
This gives greater speed for reading and writing large files, you can expect to see an improvement in loading levels in BF2 or for large photoshop files. It does not increase speed for most things infact due to the way it works it?s often slightly slower for small file transfers and slightly less responsive. The big downside to this is that if one of your drives dies then you lose all the data on both drives.

RAID1 (2 drives minimum)
This gives slightly greater speed for reading files, but no improvement for writing, what it does is give you redundancy. If one drive in a RAID1 array dies then all your data is backed up in real time on the other one. Very useful for servers where you can?t afford to lose data, or for professionals who can?t afford to lose a day?s work, should show slight improvements over single drives for loading times, but benchmarks show that any improvement is slight indeed.

Would 2 smaller drives be faster than one larger one?
Almost always, no. While it?s easy to be led to belive that RAID0 would make 2x80gb drives the equivalent of a single 160gb drive in space, and a lot faster to use it just doesn?t work like that. You would get the same 160gb of space, but the performance is usually worse in all cases, with the exception of a slight (read very slight) improvement in large file transfers. As 2x80gb drives normally cost more than a single 250gb drive which is faster than the single 160gb it?s a rather silly thing to do. For the raptor family at least 2x36 raptors are slower in everyway than a single 74gb, and 2x74 are slower than a single 150gb.

Are you saying that RAID has no use in gaming/single user computers?
Not at all, but unless your budget allows you to start using RAID for very fast drives (Raptor 150 or the faster 7200 RPM drives) then you?re normally better off just going for a single faster single drive.

 

[Bobthelost]

SCSI
SCSI is a type of connection standard, like SATA or PATA. However SCSI is mostly used in server environments, high speed (10,000rpm to 15,000rpm) and high reliability are the trademarks of it, however they also come with high cost and the need for a separate SCSI controller to use the drives in a home system.

Is SCSI the fastest system there is?
Yes, undoubtably, even the wonderful Raptor 150 can?t keep up with 15k 147gb drives. For performance in any situation a top of the line SCSI system is unbeatable. There is a cost to this, the 147gb drive are anywhere up to 3x the price of a Raptor 150 when new, making them exceedingly expensive, if you can find refurbished ones then the price drops notably but for speed they are unbeaten.

Does this mean my 36gb 15k SCSI Drive is faster than a Raptor 150?
No, it isn?t. As I mentioned earlier smaller drives = slower drives. While 147gb SCSI drives are faster than a raptor in nearly every test 74gb SCSI drives are almost all slower than the Raptor 150, and 36gb drives are even slower than the 74gb drives. As such if you have a choice between a 36gb SCSI drive (and controller) and a Raptor 150 for the same price then you should really chose the Raptor, if it's a choice between a Raptor 150 and a 147gb fugitsu MAU then the SCSI option wins.
Source: http://www.storagereview.com/comparison.html

Why isn't SCSI best suited for single user applications?
The exact reasons are beyond this FAQ, and probably beyond me for that matter, but the short version is that SCSI has been optimised for a different task than desktop dives. In a server role the access paterns seen are very random in nature, whilst for single user applications the time spent "seeking" to the data you want to find is massivly reduced. Meaning that the main advantage of SCSI drives is not being used. The raptor 150 are designed to be a middle ground between SCSI and 7200rpm desktop drives, as such they were optimised for more predicatable access paterns. I cannot stress enough that if you want more information on this topic then google, storage review and wikipedia should be your next stops.

 

[Bobthelost]

Which drive should I buy?

Speed freak, already has top end components everywhere else money not really an object:
Western digital Raptor 150gb 10k.
The fastest SATA drive there is, but at around $300 (that?s 2$ per gb) it?s not economical in any way. This should be the last bit you shell money out on for gaming as hard drive performance will only really kick in for map loading times, and the difference there is often only fractions of seconds. But if you can get it then you?ve got great epenis waving ability.

Average user/gamer
Western Digital 400gb caviar edition 16mb cache (WD4000KD) or
Hitachi Deskstar 250gb 16mb cache (7k250)

The bigger the better is the rule here, the WD4000KD is almost as fast as the smaller raptor 74, and it has a lot more space on it. The Hitachi drive is the fastest 250gb drive around, also very quick. You may be tempted by a raptor 74gb as a boot disc, which is possible but it's not all that much faster than a normal 7200 rpm drive, not worth it imo.

Audio freak:
Samsung spinpoint, model dependant on how much size you need.
2.5? laptop drive

The Samsung spinpoints are the quietest line of 3.5? drives around at the moment, second choice is Seagate although the silent community is no longer as enamoured of them as they used to be. If you want really quiet then you should think about a 2.55400rpm laptop drive, they have terrible performance, but they are much, much quieter than desktop drives. For more information on quiet computing or on quiet hard drives check out http:/www.silentpcreview.com the forums are a great resource.

Waranties
At present the best warranties for home users is the seagate 5 year one. If you're not interested in blinding speed or ultra silent running the segate baracudas (which are still fairly fast and fairly quiet) are a very good option.
Western digital offer a 5 year warranty on thier raptor lines and some of thier other SATA drives, but generally they only give a 3 year warranty.
As far as i know all other manufacturers give a 3 year warranty across the board. Corrections welcomed.

 

[Bobthelost]

IDE drives, master and slave

IDE cables 40pin and 80 pin

IDE cable select
http://www.pcguide.com/ref/hdd/if/ide/confCS-c.html

PROBLEMS SECTION:

Why does my drive only show 132gb?
You're still using service pack one, this is a stub that i'll fill out later but don't worry too much. Upgrade to SP2 and then use a disk management tool to correct the problem.

 

[JimPhelpsMI]

Hi, This looks great! Don't forget to add a section about IDE Cables, Standard and Cable Select and how to set the jumpers etc. Jim

 

[poisonthewell]

great job. suggestion:

which drive should i buy?

a little surprised nothing is mentioned concerning warranties. for many people the length of warranty ends up as THE deciding factor when choosing one drive over another. it's certainly why a lot of people (including myself) go with seagate.

 

[bwnv]

How about mentioning the 132Gb limit of XP with no service packs, that comes up at least once a week.

 

[cleverhandle]

Without getting into too much detail, I think the SCSI section could use some explanation of data locality and firmware. The 150G Raptor is pretty much the absolute best drive around for single-user scenarios at the moment. To understand why, you need to understand that there's more to drive performance than raw speed. The Raptors are great drives not only because of their mechanicals, but because they're well-tuned for desktop performance. Server-class SCSI drives, while mechanically superior, have server-oriented firmware - that makes them, at best, an extremely expensive near-equivalent to a Raptor.

 

[Madwand1]

This would be fine if things, esp. performance questions, were as cut & dried as the FAQ makes them seem. Reality is very complicated, and the issues are hardly straightforward and amenable to universal rules or simple answers. If these are to be taken as some sort of reference, then they should be backed up by significant evidence and caveats where approriate.

For example, I have in my hands evidence of a SATA 3.0 version of a drive with greater sustained transfer rates than the SATA 1.5 version of the same drive in single-drive usage So this is not mere marketing, and it may well be worthwhile in some cases to pursue the the newer drive, and the statement about SATA 3.0 just being marketing hype is misleading.

My opinion is that this task is best left to boards which specialize in this area, such as Storage Review, which makes a continuous effort to back up assertions (which continue to be debatable) with signficant empirical evidence.

 

[Bobthelost]

Madwand1 you're right it is best left to sites like storage review, i'll make it more clear in the SCSI section (and RAID) that it's a very very simplified FAQ and that storage review will have more (and better) advice on all the topics.
I'm interested in this drive of yours, i'll add a bit to the effect that there are some small advantages seen with the 3.0gbs, but that it's mostly marketing hype (which it is imo).

Cleverhandle, yep, good point i'll add a bit to that effect in the SCSI section.

bwnv: I knew there was a reason i left that last post...

poisonthewell: Yep, that would be helpful wouldn't it.

JimPhelpsMI: Yep, another thing for the last post i think.

Taking a bit of a break, will update the stubs for IDE cabling and master/slave.

 

[alimoalem]

i agree, posting which drive to buy would be good. there are a lot of people with $500 budgets that can't afford the 250gb+ drives. maybe posting a "best hard drive" for each storage size would be nice.

i feel you could've gone a bit more in depth on a lot of topics. also, you mentioned your opinion in a lot of places so to keep the article neutral, i would just mention the benefits/negatives of 2 options instead of just saying "it's mostly marketing hype (which it is imo)" if you actually check out the benchmarks, the 3.0 is faster. you may be right it's not because of the 300mb/s transfer rate but the newer technology used for the drives. the way you say it makes it sound like there is no benefit, period.

i may be wrong but what i said is my understanding of the subject. nonetheless, this is a very well written FAQ and i feel it'll help many in the future, although the posts on "which hard drive should i get?" will continue to come in masses.