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Thread: Hard Drives and my quest to be a tech geek

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    Hard Drives and my quest to be a tech geek

    OK here is the question:

    Let's assume I just bought an external hard drive: 100gb 7200 that can be hooked up as eSata, FireWire 800, FireWire 400 or USB 2.0

    How big a difference is there between running the drive off the different connections?

    If there is a big difference, and you don't have the fastest port, then is it worth buying the fastest drive?

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    Senior Member Robert Campbell's Avatar
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    Re: Hard Drives and my quest to be a tech geek

    This seems a very modest drive.
    I understood - I may be wrong - that eSATA isn't hot swappable, so it must be on all the time.
    I have a drive which can be connected by USB [2] or FW [400] and it seemed much quicker on FW.
    It isn't difficult to run out of USB ports - FW seems to have the advantage here.
    I also gathered that the limiting factor is the speed of the drive itself.
    Sláinte

    Robert.

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    Re: Hard Drives and my quest to be a tech geek

    That one is the modest "travel" drive. The others are 1TB.

    That is sort of the question, what hits the limit... So, for instance on USB 2.0 would you get the same performance from a 5200 and a 7200 drive? But on FireWire 800 you will see the difference in drive speed between the two?

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    Senior Member Robert Campbell's Avatar
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    Re: Hard Drives and my quest to be a tech geek

    Quote Originally Posted by TEBnewyork View Post
    That one is the modest "travel" drive. The others are 1TB.

    That is sort of the question, what hits the limit... So, for instance on USB 2.0 would you get the same performance from a 5200 and a 7200 drive? But on FireWire 800 you will see the difference in drive speed between the two?
    Get a USB 'travel drive' - you don't need any extra power source.
    For a PC reformat from FAT32 to NTFS - I know nothing about Macs

    Otherwise, I must pass...sorry!
    Last edited by Robert Campbell; 4th March 2008 at 15:33.
    Sláinte

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    Re: Hard Drives and my quest to be a tech geek

    Quote Originally Posted by Robert Campbell View Post
    Get a USB 'travel drive' - you don't need any extra power source.
    For a PC reformat from FAT32 to NTFS - I know nothing about Macs

    Otherwise, I must pass...sorry!

    Thanks,
    I'm on Mac.

    Actually, I can also run FireWire without power as well. I am changing around a lot of system stuff all at once and have some new drives and old drives so I really just want to get the right parings and make sure I understand what limits what.

    terry

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    Re: Hard Drives and my quest to be a tech geek

    # USB2 = USB 2.0 port rated at 48MB/s
    # 1394a FW400 = FireWire 400 port rated at up to 40MB/s
    # 1394b FW800 = FireWire 800 port rated at up to 80MB/s
    # SATA = SATA port rated at up to 150MB/s
    # SATA2 = SATA II port rated at up to 300MB/s

    So, in theory, your drive should be able to do up to 300 MB/s.

    Pick which one works best for your needs and go from there.

    Personally, I run USB 1.0 and 2.0. 2.0 is 'okay', but when I'm accessing stuff via eSata, I'm in heaven. It's like the external drive is an internal drive, it's so fast. I do this because I've only got a single fire-wire cable, but tons of USB cables. YMMV.

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    Re: Hard Drives and my quest to be a tech geek

    Well, you can't get it off the drive any faster than the platter rotates. Also it depends a lot on how you use it. I will assume that you are reading sequentially very large files (this is an optimistic assumption, since other usage modes will be slower)
    Assuming that it performs like a seagate 7200.2, then the maximum sustained transfer rate (sequential multi sector reads) is 59.0 MB/sec. That is rarely achieved because it requires that disk requests come in in just the right order and at the right time to reduce latency. More usual field experience might be somewhere about half of this.
    At USB2.0 rates, you will not be bottlenecking this drive so as long as you are at USB 2.0 or better, it won't make a difference.
    Compare this to say the seagate 7200.11 drive which transfers at 105MB per sec sustained actually might be bumping up a little on the USB2.0 rates, and thus might benefit from Firewire 800.
    I have measured eSATA and firewire 800 disk performance and found it to be more a function of the driver than the interface. I have a specific pc (a Toshiba) that transfers twice as fast across firewire 400 than my macbook pro, which is usually about twice as fast as most windows boxes (go figure). The main reason that most operating systems work better in eSATA is that 1) it is the native direct interface for internal disks and 2) It is a point to point interface which does not require arbitration to select a particular device. I would not be surprised to find the arbitration delays to be the major bottleneck in all USB and Firewire implementations and not the actual transfer rate. Bottom line, with that particular drive you will not be able to observe much difference between any of the "bus" type interfaces (USB2.0, Firewire 400 or 800) but might see a little difference in eSATA, but probably not enough to make a real difference.
    Now if you had a seagate Cheetah 15k.5 drive, which spins over twice as fast, it can sustain a transfer at up to 125 MB per sec even though its physical interface (4Gb Fibre channel) can support about 400GB/sec.
    Oh, folks might say "what about the cache in the drive...", well all that usually does is get your sector by sector read commands (as they come from the OS) begin to approximate the off-the-platter sustained read speed since the drive will fill the buffer (usually) with a full track of data even though a single sector might be currently at the head of the queue. It is far better to have it in a buffer than to suffer what might be nearly a full latency (time it takes the platter to come all the way around) before the next sequential sector comes under the heads again since probably the OS didn't quite make it in the inter sector gap. Note that even though buffered, the bits don't come off the platter any faster, you need that buffer to smooth out the synchronization delays between os, interface, seeks, and platters.
    One interesting example of how this really applies in practice is that the Lacie "BigDisk" (I think that is what is called) is formatted with a striped raid, so that there are two drives supplying data in parallel to the interface. They did this in order to take advantage of the firewire 800 interface. A single non-semiconductor drive cannot provide it data as fast as it can eat it today.
    Now if you are talking a raid controller card such as what is offered for the MacPro, then it has the capability of transferring from up to four drives in parallel over independent sata channels. Now that is now to take advantage of SATA!
    -bob
    Last edited by Bob; 4th March 2008 at 18:20.

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    Re: Hard Drives and my quest to be a tech geek

    I don't think MacBook Pros can use eSata drives. Or they might need a PC card. Anyone?

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    Re: Hard Drives and my quest to be a tech geek

    Quote Originally Posted by Maggie O View Post
    I don't think MacBook Pros can use eSata drives. Or they might need a PC card. Anyone?
    There is an eSata card that you can use....

    http://eshop.macsales.com/item/Apiotek/EC0003D/

    There is a lot written on it in this thread (it is a loooong thread):

    http://forum.getdpi.com/forum/showthread.php?t=875

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    Re: Hard Drives and my quest to be a tech geek

    Ah, I thought that might be the case.

    I just bought two OWC Mercury Elite Classic 500GB FW 800 drives, myself.

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    Re: Hard Drives and my quest to be a tech geek

    Bob,
    I'll say thanks right now but I am only on my third read through and it is going to take me some time to digest all that you have written. I'll probably be back with some more simpleton questions soon....

    terry

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    Re: Hard Drives and my quest to be a tech geek

    Quote Originally Posted by Bob View Post
    [SNIP] [SNIP]
    -bob
    Or what Bob said!

    FWIW, some online techy site (Tom's Hardware, Anatech, PC Extreme, or one of them) did a test between a striped Raid versus a mirrored raid to see performance differences. It was shockingly and appallingly small. Like 2-3% improvement for a pair of 7.2k spin drives. Going to a single 15k drive was significantly better than a striped raid. For multiple reasons (lose a single drive and lose all data (integrity). I'll see if I can find the info but I'm dash out the door right now to meet up for dinner.

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    Re: Hard Drives and my quest to be a tech geek

    I tested the same drive over a FW400 and FW800 interface on my MacPro, and found FW800 was 15% faster. I used IOMeter to test, with a typical file server load (80% read, 20% write, 100% random hard drive head seeks, lots of different block sizes), as defined by Intel. As was said earlier, a lot depends on the drive as well.

    That said, I have all of my images on an external USB drive at home, and just the Aperture catalog on my internal drive, and the speed is fine.

    It all boils down to what you need, and how fast is fast enough?

    -Scott

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    Re: Hard Drives and my quest to be a tech geek

    If there is a big difference, and you don't have the fastest port, then is it worth buying the fastest drive?
    I forgot - it was said earlier, but a faster drive will help on USB all the way to eSATA. The drive head will rotate faster, and you will, at the very least, get to your files faster.

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    Re: Hard Drives and my quest to be a tech geek

    Here is the bottom line...

    SATA speeds refer to maximum BURST rates in BITS (b) per second, NOT BYTES (B) per second. So, SATA2 runs at maximum BURST at 3 Gb/s, or about 300 MB/s. SUSTAINED read and write, like what we do with images, is MUCH slower even on SATA2 drives.

    My BEST SATA2 drives are capable of just over 100MB/s on SUSTAINED read or write tapering off to 70MB/s or so toward the slow end of the drive, so FW800 at 80 MB/s is for all practical matters pretty darn close... SATA1 drives only ran at about 50 MB/s to begin with, so not even significantly faster than USB2 or FW400... Fortunately, SATA2 drives are twice as fast. BTW, this is why you need to remove the jumper on Seagate SATA2 drives, as they default to SATA1 speeds if the jumper is left on

    The other problem with eSATA is it is NOT hot-swappable or hot-bootable. Hence, the only time I would say it makes a difference on an EXTERNAL drive, is on a desktop where it's permanently connected via eSATA, or for when you want to transfer more than a couple hundred GB and have limited time on a laptop. Otherwise it is not worth having to shut the computer off, connecting eSATA and rebooting to run it. By contrast, the convenience of plug&play FW800 is a breeze on a laptop or a desktop for transferring even a few hundred Gigs of images...

    These are the reasons I didn't recommend the eSATA version portable drive box for your laptop: I didn't feel it was worth the cost difference to gain a function you probably would only rarely or never use with your laptop. However, I feel the opposite is true for a desktop: I have my desktop external drives connected by eSATA since I don't need to disconnect them and use them just like internals, so the lightening fast burst and faster sustained R/W is welcome.
    Jack
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    "Perfection is not attainable. But if we chase perfection, we can catch excellence."

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    Re: Hard Drives and my quest to be a tech geek

    What Jack said.

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    Re: Hard Drives and my quest to be a tech geek

    Jack - if you wanted to use an external drive as a scratch disk for a laptop when traveling would you then recommend eSATA over Firewire 800 - or not bother at all?
    Last edited by cmb_; 5th March 2008 at 09:08.

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    Re: Hard Drives and my quest to be a tech geek

    I confess there was a dirty little secret built into my question. I was back to thinking about the MacBook Air as the only time I need Photoshop on a laptop is at a workshop and normally would do that type of work on my desktop. With the addition of RAM and a big Firewire 800 SATA2 for the desktop I'm feeling pretty good (or will tonight when I figure out what the jumper is and install the new drive - which arrived).
    On a MBP, I also understand what a good setup would be. I was trying to figure out if I would want to shoot myself being limited to USB2.

    Now, I have a much better grasp on the detail which makes my brain happier!


    Quote Originally Posted by Jack Flesher View Post
    Here is the bottom line...

    SATA speeds refer to maximum BURST rates in BITS (b) per second, NOT BYTES (B) per second. So, SATA2 runs at maximum BURST at 3 Gb/s, or about 300 MB/s. SUSTAINED read and write, like what we do with images, is MUCH slower even on SATA2 drives.

    My BEST SATA2 drives are capable of just over 100MB/s on SUSTAINED read or write tapering off to 70MB/s or so toward the slow end of the drive, so FW800 at 80 MB/s is for all practical matters pretty darn close... SATA1 drives only ran at about 50 MB/s to begin with, so not even significantly faster than USB2 or FW400... Fortunately, SATA2 drives are twice as fast. BTW, this is why you need to remove the jumper on Seagate SATA2 drives, as they default to SATA1 speeds if the jumper is left on

    The other problem with eSATA is it is NOT hot-swappable or hot-bootable. Hence, the only time I would say it makes a difference on an EXTERNAL drive, is on a desktop where it's permanently connected via eSATA, or for when you want to transfer more than a couple hundred GB and have limited time on a laptop. Otherwise it is not worth having to shut the computer off, connecting eSATA and rebooting to run it. By contrast, the convenience of plug&play FW800 is a breeze on a laptop or a desktop for transferring even a few hundred Gigs of images...

    These are the reasons I didn't recommend the eSATA version portable drive box for your laptop: I didn't feel it was worth the cost difference to gain a function you probably would only rarely or never use with your laptop. However, I feel the opposite is true for a desktop: I have my desktop external drives connected by eSATA since I don't need to disconnect them and use them just like internals, so the lightening fast burst and faster sustained R/W is welcome.

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    Re: Hard Drives and my quest to be a tech geek

    Quote Originally Posted by TEBnewyork View Post
    I confess there was a dirty little secret built into my question.
    Ah, female wiles again...
    Sláinte

    Robert.

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    Re: Hard Drives and my quest to be a tech geek

    Quote Originally Posted by Robert Campbell View Post
    Ah, female wiles again...
    That would be feminine wiles, Robert. Not all females are wily.

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    Re: Hard Drives and my quest to be a tech geek

    Quote Originally Posted by cmb_ View Post
    Jack - if you wanted to use an external drive as a scratch disk for a laptop when traveling would you then recommend eSATA over Firewire 800 - or not bother at all?
    Unfortunately, the answer here isn't as simple...

    The biggest issue with eSATA on a laptop is it is NOT a direct SATA connection to the MB, but rather goes through via the smart-card I/O port. Depending on the adapter and your system, the net transfer speeds may not be any faster than SATA1 and may in fact not even be that fast, meaning you'd be better off using FW800 or possibly even USB2/FW400(!) OTOH, if your system allows a flow though at true SATA2 speeds, then the combined burst and sustained rates will give eSATA a notable advantage even over FW800 on a scratch drive.

    If one feels the need for a true scratch disk on a laptop, I would suggest the techiest move would be to remove the internal DVD drive and replace it with a second laptop drive. Also probably best if that DVD drive is also SATA2 since IDE is slower enough that FW800 may be as good...

    Frankly, this is where we get to the point that a dedicated desktop delivers superior performance for digital imaging. A laptop has limited I/O bus speeds, limited RAM capacity and RAM bus, and does not generally support additional drives as conveniently. In addition, the biggest performance upgrade will be achieved with a direct-to-MB RAID array, again not supported very well in laptops...

    At the end of the day, this is why I don't generally worry about scratching on when on my laptop, and moreover, tend to work in 8-bit mode: I know I'm going to re-work my serious images on my big machine before printing or delivering to a client anyway.

    However, One thing I've considered is a really fast, larger capacity SD card might make a respectable scratch drive if connected via a fast smart-card reader/writer Don't know how well it will work, but need to pony up for a fast 16G card and try it...
    Jack
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    Re: Hard Drives and my quest to be a tech geek

    Quote Originally Posted by Maggie O View Post
    That would be feminine wiles, Robert. Not all females are wily.
    I stand corrected: but it reminds me of Mrs Margaret Thatcher, one time Prime Minister, whose deputy was Mr William Whitelaw. Mrs Thatcher is supposed to have said that 'every Prime Minister needs a Willie'.
    Sláinte

    Robert.

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    Re: Hard Drives and my quest to be a tech geek

    There a few different things that effect this;

    Drive speed (when using a single 7200 rpm drive and something other than RAID)
    ---
    USB -- 7200 is fine, USB is way slow
    1394a -- 7200 is fine, 1394 is a touch quicker than USB, but won’t tax a 7200 drive
    1394b -- Here 7200 starts to show it’s limits, 1394b as indicated earlier does cap out at 80MB/s for S800. At S800 you should get about
    60MB/s for writing
    70MB/s for reading
    eSATA -- 7200 drives are a bottle neck on eSTAT and I haven’t see a boxed product that ships with an 10,000rpm drive yet

    Bridge Controller
    --
    The bridge controller in the drive enclosure will effect the perf on the case. There are only a few companies that make storage bridges (InitI|O, Oxford Semiconductor, Prolific, etc…) and everyone else sells them in their case/product (be it LaCie Seagate, Western Digital, etc…). To my knowledge there is only one company that provides a ‘quad’ board – Oxford Semiconductor. In my experience, the chipsets that Oxford sells are great, but you need to watch the firmware rev to make sure you’re getting max perf. across all busses on the bridge.

    Non-obvious
    --
    CPU hit during transfers -- CPU impact varies wildly between BUS’. HDTune (http://HDTune.com ) is a util for PCs – they have freeware and ~$45 versions – that will show you the CPU hits range somewhat like this:

    eSATA ~ 10%
    1394a ~ 15%
    1394b ~ 30%
    USB ~ 35%

    with the same drive in a multi bridged enclosure running the same test on the same drive just changing the connection to the computer.

    At some point in the future, we might see Mutli-Core systems help off load some of the impact to CPU hits, but given Intel drives USB specs, and sells processors I could see USB CPU usage continuing to be high into the USB 3.0 range. 1394 is designed to share the transfer speeds between controllers and devices.

    Power Supply -- The power supply will effect speeds on these as well. When you are using these devices for travel, you should try to make sure you carry the actual wall wart that comes with your product and avoid using USB bus power. USB bus power is horribly taxing to battery life on a laptop that isn’t plugged in, and if you are using fast drives they will be thirsty. 1394a / 1394b both provide bus power provided the host controllers are powered correctly (e.g. 1394a ‘four pin’ adapters do not provide power). I can’t recall if eSATA does now, or will soon support power. And anything running over an ExpressCard or PCCard / PCMCIA adapter will be limited as to how much, if any, power will show up on that adapter.

    To Jack's thinking about as SD slot/card for swap – the reader in most laptops these days is attached via USB and it is an interesting trade off to put swap on the system if it impacts CPU. If you are using a 1394 based reader that’s ok and I haven’t seen a SATA/eSATA one yet.
    -- M.

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    Re: Hard Drives and my quest to be a tech geek

    Quote Originally Posted by MrSlezak View Post

    To Jack's thinking about as SD slot/card for swap – the reader in most laptops these days is attached via USB and it is an interesting trade off to put swap on the system if it impacts CPU. If you are using a 1394 based reader that’s ok and I haven’t seen a SATA/eSATA one yet.
    I'm actually suggesting trying it through the express card port, which is pretty fast -- 5Gb/s I think? Anyway, lots faster than usb2, FW400 and FW800... Using it, a good reader/writer and a fast 16 GB SD card might be interesting.

    Cheers,
    Jack
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    "Perfection is not attainable. But if we chase perfection, we can catch excellence."

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    Re: Hard Drives and my quest to be a tech geek

    Ah, ExpressCard might not be a bad route to take for swapping... That I hadn't considered (keep forgetting there are ExpressCard devices out there... )
    -- M.

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