OS Drive

[AriciU]

It's finally time to change my trusty, 3 year old, WD 160GB IDE HDD that i have used for XP and Vista. I'm looking for a drive that will really improve performance and startup time. The Velociraptor is too expensive for me at the moment.

I was thinking of getting an aditional WD 640gb as they are dirt cheap and the performance is very good as shown by reviews. Do you think i'll really see some noticeable improvement over my 160GB IDE drive? Do you recommend any other drive?

[MikeB12]

I do.. especially if you slice the first partiton off to like 100gb for the os only... so it spins up on the outside of the disk..

[stevecs]

Depends on your workload, but basically a higher bit density of a drive will give you better streaming speeds, and higher rotational latency will give better access times. What you can do is get a new drive (highest bit density/platter you can find in your price range) and then partition it so the first 10% or so is for your OS and the rest of the drive for slower access data. You can improve on this more by just clipping (only using the outer say 10%) of the drives and get a bunch of them to give you the space you need.

[Soulburner]

Depends on your workload, but basically a higher bit density of a drive will give you better streaming speeds, and higher rotational latency will give better access times. What you can do is get a new drive (highest bit density/platter you can find in your price range) and then partition it so the first 10% or so is for your OS and the rest of the drive for slower access data. You can improve on this more by just clipping (only using the outer say 10%) of the drives and get a bunch of them to give you the space you need.
This works only if you use an actual slice though right? How does windows determine what portion of the disk becomes a partition?

About the topic...if you were to upgrade your main disk from your 160 (which is like 2x80GB platters) to the WD 6400AAKS (which is 2x320GB platters) you would see roughly a doubling in transfer speeds and faster loading times for everything.

[WhiteFireDragon]

yeah im wondering the same thing. how can you actually tell Windows to install to only the outer portion of the platter?

[stevecs]

You create the partition (ie, when you install a fresh OS or if you plug the drive into another computer and go to your disk management program). A partition map is a logical construct which basically identifies what sectors to use. by default partitions are laid out starting from the outer track going inward on a drive, the outer tracks have the fastest linear velocity so in conjunction w/ high bit densities it gives the fastest streaming performance. By laying your first partition for your OS there you are basically setting a known performance rating of the speed (ie, sectors are /always/ within the tracks of that 10% or whatever you carved up so they all have the same performance. If you were to also ONLY use this part of the drive (ie, not even use the rest of the drive for anything, leave un-partitioned/formatted et al) then it would also increase your access times as you are not seeking to the other locations of the drive. (arm movement is less). This is how you would get the best performance out of a drive. If you can't or don't want to dot that your access times and IOPS are then spread out across everything on that disk.

[MikeB12]

I may be wrong.. but I thought the first partition created on a unpartitioned disk is always assigned to the outside...
so just install the disk, create one small partition for the os during install... and create the data (second) partition after windows is installed.
then the os always runs on that first partition, which resides on the outer part from the way it was created.

edit: too late, steve beat me to it..

[stevecs]

But yours is probably more concise of an answer. :P

[AriciU]

Wow. This thread filled up fast :) I'm gonna get a WD 640 tommorow and partition like this:

1st partition, 50Gb XP
2nd partition, 50Gb Vista
3rd partition, rest of free space for Games/Apps/Downloads/Torrents/ETC

Or since there are 2 x 320gb platters it would be better to make the XP/Vista partitions 160GB each?

[Soulburner]

Do you plan on having your two operating systems share the programs and games on the 3rd partition? If so, it may not work for some programs and games since they will only be "installed" to one and the other will not be aware of them, giving you errors when you try to launch them. Many things do work this way but some won't load until you actually install them within that OS.

Just something to think about.

[AriciU]

Do you plan on having your two operating systems share the programs and games on the 3rd partition? If so, it may not work for some programs and games since they will only be "installed" to one and the other will not be aware of them, giving you errors when you try to launch them. Many things do work this way but some won't load until you actually install them within that OS.

Just something to think about.

No, each OS'es programs will be installed on the OS's specific partitions. By programs on the 3rd partition i meant stuff like CPU-Z, application installers, things like that. Bassically, stuff :)

[khamsin]

You create the partition (ie, when you install a fresh OS or if you plug the drive into another computer and go to your disk management program). A partition map is a logical construct which basically identifies what sectors to use. by default partitions are laid out starting from the outer track going inward on a drive, the outer tracks have the fastest linear velocity so in conjunction w/ high bit densities it gives the fastest streaming performance. By laying your first partition for your OS there you are basically setting a known performance rating of the speed (ie, sectors are /always/ within the tracks of that 10% or whatever you carved up so they all have the same performance. If you were to also ONLY use this part of the drive (ie, not even use the rest of the drive for anything, leave un-partitioned/formatted et al) then it would also increase your access times as you are not seeking to the other locations of the drive. (arm movement is less). This is how you would get the best performance out of a drive. If you can't or don't want to dot that your access times and IOPS are then spread out across everything on that disk.


But on which platter? I'd assume that most (if not all) of today's high capacity drives are multi-platter disks. Then, the 'best' performance would come from the first partition as well as portions of other partitions that correspond to the outer edges of the other platters. Right?

How does NTFS know which platter to use? I don't think it does.

Or does it create the first partition equally across the platters -for eg: a 10GB partition on a 3 platter drive as 3.34 GB on each platter; or does it create a single 10GB partition on the first platter?

What about RAID? How does NTFS partition then?

AFAIK, the data mapping at the physical level of the block is done by the drive's in-built hardware/controller; not by NTFS which sees only the logical block and not the physical block. The logical block is translated into the physical block by the harddrive's driver (or maybe in-built controller, not sure exactly which one) when reading or writing data to the drive, and NTFS has no direct say in determining what goes where.

If I am wrong, I'll gladly be corrected.:)


As for the OP, I switched from a 250GB drive to a 500GB OS drive (yes, partitioned, but for other reasons) and performance has definitely improved. I suspect that has a lot to do with the increase in the areal bit density of the larger drives.

You should definitely see an increase when going from 160GB to 500/640GB, under normal circumstances.

[stevecs]

Don't worry about platters, you use both. Basically there are multiple heads so say you have 2 platters you have effectively 4 heads and 4 tracks you can read from the sectors are read with minimal head movement (assuming streaming/consecutive sectors). All the heads are attached to the same armature which is why this is done. So in real-world work you just need to know how much space is needed for your fastest partition (say 30GB or whatever) and as long as that is first, all of that will be on the fastest part of the drive.

NTFS or any filesystem has no clue about anything at the disk level. The partition map (the actual layout of the drive that you set up) is what is allocating the presented sectors to be used for that partition (note, there is no filesystem here at this stage this is just raw sectors that _whatever_ i/o driver can use for that construct). You then format that with a filesystem (ntfs or whatever) which since you are formating that partition it is locked into the sectors that the partition has.

RAID is another level. It does not change the above it just abstracts it more. For example you have 4 drives, if you add those drives to a raidset that now acts as your 'physical' disk. When you create a volumeset under that raid set (say you had 4 100GB drives and create a raid volumeset of 10GB) then assuming a RAID-0 here the first 2.5GB of each drive will be used. This is similar to partitioning in that respect but don't get confused as partitioning is not the same thing (layers would be basically, physical disk, raidset, volumeset, partition, logical volume managers, software-raid, filesystems, OS).

And not to throw to much of a mental wrench in here but for completeness the 'sectors' you see (anything outside of the physical drive itself like raidset, volumeset on up) are also abstracted, the only device that /really/ knows what sector it is is the drive controller itself, this is even more true for flash or SSD drives.

[khamsin]

Don't worry about platters, you use both. Basically there are multiple heads so say you have 2 platters you have effectively 4 heads and 4 tracks you can read from the sectors are read with minimal head movement (assuming streaming/consecutive sectors). All the heads are attached to the same armature which is why this is done. So in real-world work you just need to know how much space is needed for your fastest partition (say 30GB or whatever) and as long as that is first, all of that will be on the fastest part of the drive.

So, if a 2 platter (i.e. 4 surfaces and 4 r/w heads) drive of total capacity 400GB (100GB on each surface) is partitioned into 2 partitions of, say, 20 GB and 380 GB, then the 20 GB partition would correspond to the first 5 GB (starting from the circumference) of each surface. The rest of the 380 GB would correspond to the remaining 95 GB on each surface, but 5 GB worth of 'tracks' (i use the term loosely) away from the circumference.

This sounds logical.:yepp:

[stevecs]

Yup. :)