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  1. #1

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    The most common thing with tiger upgrades people have been facing is lack of Ram (Memory) as we all know putting memory in a powerbook or ibook isnt an easy process to do yourself and isnt a cheap process to get an apple centre to do it.

    The cheapest solution is one of the advantages of the BSD core OS.
    Plug in a USB 512Mb or 256Mb flash card.
    You need to setup a RAM Drive you can use an application which is the easiest way download (http://www.northernsoftworks.com/tigercachecleaner.html) their are other applications that can do this or you can use terminal to create it manually i may post a followup on creating it manually in terminal if people are interested.

    Once setup when your memory is full it will load data into the RAM drive instead of the swap file thus being a bit faster then an internal hard drive.
    Though memory would be faster this is an easy hack for anyone who doesnt have enough bays for a memory upgrade or doesnt want the machine opened.

  2. #2

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    Can this be done with 10.2.8? Would be interested, esp in the terminal version.

  3. #3

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    Isn't the throughput of USB2 really only about 50mb/s? Surely your internal hard drive would be faster than this.
    13 inch MBP :: 32Gb iPod Touch

  4. #4

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    Ok this program is alot more simple.

    http://www.donelleschi.com/ramdiskcreator/

    select the size of the ram disk
    select the mount point of the flash card or device your using and tell it to create.

    As for a terminal version its going to be a bit harder to do as the device names will be different and typing in the wrong name will format your hard drive

  5. #5

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    Originally posted by bergerac@May 25 2005, 02:05 PM
    Isn't the throughput of USB2 really only about 50mb/s? Surely your internal hard drive would be faster than this.
    USB 1.0/1.1 support data transfer at up to 1.5 Mbps for low-speed devices and up to 12 Mbps for full-speed devices.
    USB 2.0 will support up to 480 Mbps for high-speed devices. USB 2.0 is suitable for high-performance devices such as high-quality video conferencing cameras, high-resolution scanners, and high-density storage devices.

    I would suggest though check your system profiler under utils which will have a USB section that should tell you what speed your flash card will be running at.
    usb2.0 devices should be quicker then a hard drive since flash is instant access also if your hard drive is already maxed out with requests atleast the usb bus will have some spare grunt

  6. #6

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    The actual throughput of a USB 2.0 device would be much less than a internal HDD.
    Good in theory though - perhaps not practice.
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  7. #7

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    But you'd hate to accidentally knock it out of the port....

    EDIT: re. the speed, i'd imagine it would depend on the speed of the HDD to, ie perhaps better for laptop users with slow HDDs (who would be more likely to need an alternative to actual RAM, having less slots

  8. #8

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    A RAM drive is a virtual hard drive that is created by using a segment of RAM.
    Virtual Memory / swap file, uses a storage device (hard disk, usb key) as a RAM overflow.

    EDIT: typo
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  9. #9

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    in a powerbook a hard drive is 4200 RPM standard.
    4200 RPM drive is about 30 MB/s max throughput so flash will be faster then swap but slower then actual memory


  10. #10

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    If you do this, be prepared for the fact that you will kill your flash drive.

    Flash drives are designed for only a few thousand cycles. Using them as RAM means you will chew through this very quickly, as each change your make to "RAM" will cycle that bit.

    This is the reason when people build small PC's with Flash as HD's they turn off the swap file in windows, and make sure they have heaps of real RAM.
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  11. #11

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    Originally posted by josh64@May 25 2005, 02:16 PM
    A RAM drive is a virtual hard drive that is created by using a segment of RAM.
    Virtual Memory / swap file, uses a storage device (hard disk, usb key) as a RAM overflow.

    EDIT: typo
    thats what i mean it wont "replace" memory it will simply use it instead of swap, so when the ram is full it will use the ram disk as well.
    better using a ram disk of flash then your hard drive swapping while your loading an application and its trying to load it into the swap file as well.

    Its only a suggestion for those who want to get a little more speed without having to do an internal upgrade.

  12. #12

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    Originally posted by Mac Aid@May 25 2005, 02:17 PM
    If you do this, be prepared for the fact that you will kill your flash drive.

    Flash drives are designed for only a few thousand cycles. Using them as RAM means you will chew through this very quickly, as each change your make to "RAM" will cycle that bit.

    This is the reason when people build small PC's with Flash as HD's they turn off the swap file in windows, and make sure they have heaps of real RAM.
    yeah thats one downfall which makes me wonder about the ipod shuffle

  13. #13

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    480MBits/s, Your standard desktop hdd is still faster (ATA133 = 1064Mbits/s), about equal with an ibook hdd I guess (all in theory). But it would be of advantage if the application is using (reading/writing) to the HDD aswell, aviode thousands of seeks as it switches between tasks which can seriously hamper performance.

    EDIT: my bad. probably a fair bit faster than an ibook hdd, and maybe still a powerbook hdd, but the margin will be slim.

  14. #14

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    Plug in a USB 512Mb or 256Mb flash card.
    ...
    Once setup when your memory is full it will load data into the RAM drive instead of the swap file thus being a bit faster then an internal hard drive.
    Flash drives have *much* slower read and write times that HDDs. In addition, they have to go through the USB bus. Therefore, I can't see any way that putting the paging file on a USB drive would speed anything up, but I could see it slowing VM paging down significantly.

    Also, I can't understand how you could create a "RAM drive" on the USB memory stick in the first place (since it isn't RAM). USB memory sticks are just another form of secondary storage (and not a particularly fast one at that). They can't do anything to boost your primary storage.

    My suspicion is that all you are doing via this "upgrade" is creating a RAM drive, and hence lowering your total amount of available RAM, then (possibly) putting a swap file on the RAM drive. This simply doesn't make any sense, since you would be better to leave yourself with the full amount of RAM in the first place. I can't see how your USB memory stick has any connection to the RAM drive either.

    Perhaps I am just misunderstanding what you are saying, but this "upgrade" really doesn't seem to make much sense.

  15. #15

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    Originally posted by Maticks@May 25 2005, 02:20 PM
    thats what i mean it wont "replace" memory it will simply use it instead of swap, so when the ram is full it will use the ram disk as well.
    better using a ram disk of flash then your hard drive swapping while your loading an application and its trying to load it into the swap file as well.

    Its only a suggestion for those who want to get a little more speed without having to do an internal upgrade.
    No, calling it a RAM disk is inherently incorrect.

    It's virtual memory. RAM disk it ain't.

    RAM disk is a storage device emulated in RAM space.
    Virtual memory is RAM emulated on a storage device (i.e. USB Key).

    EDIT: I'm not trying to rubbish your hint, it's a great idea. It's just worded incorrectly and conveys the wrong message.
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  16. #16

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    Another thing, my VM page file is usually around 4GB in size. I can't imagine that spliting this between two drives would be a very good idea at any rate.
    13 inch MBP :: 32Gb iPod Touch

  17. #17

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    Originally posted by Maticks@May 25 2005, 02:22 PM
    yeah thats one downfall which makes me wonder about the ipod shuffle
    Even if you update the songs on the Shuffle every day, it should last you for years. It is writes, rather than reads which are the issue with Flash memory.

    Putting a paging file on Flash memory would involve near-constant writing. This would:
    1) Be slow because Flash memory is quite slow at writing
    and
    2) Run through all the cycles of the flash memory pretty quickly

  18. #18

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    Correct me if I'm wrong here -

    - Motherboards are hardwired so that the CPU accesses RAM directly via the system bus
    - Using a USB drive as virtual memory, data now takes the flowwing path:

    CPU -> system bus -> PCI bus -> USB controller -> USB drive.

    Also, RAM is accessed very frequently - not as a continuous data stream. Add to that the fact that USB flash drives have a horrendous writing seek time when comapred with HDD, and you have some *very* slow RAM.

    Anyone who owns an external USB HDD and USB flash disk will testify that the HDD is a lot faster when writing files. And anyone with internal and external HDDs running at the same speed probably knows that the internal drive is faster again. And real RAM is *much faster* than that yet again.

    bergerac: Splitting vitual memory across different phsyical drives actually speeds things up because the two drives can both read/write at the same time. *In theory*, using 2 HDDs could double the thoughput of your virtual memory.

  19. #19

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    How slow is this memory? USB flash drives are not made for memory, there made for storage! Has anyone actually noticiced a difference?????

    Sounds silly to me!
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  20. #20

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    Originally posted by Maticks@May 25 2005, 02:08 PM
    Ok this program is alot more simple.

    http://www.donelleschi.com/ramdiskcreator/

    select the size of the ram disk
    select the mount point of the flash card or device your using and tell it to create.
    So you're mounting the RAM disk on the same mount as the USB memory key (i.e. mounting it over the top of the memory key)? This could explain why the memory key seems fast, because it is actually RAM you are accessing, not the memory key.

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