• Yokemate of Keyboards
    Yokemate of Keyboards
    Andreas_Wolf
    Posts: 12058 from 2003/5/22
    From: Germany
    >> MaxTransfer

    > Not 100% sure, but I think I read somewhere
    > that the option was deprecated after 2.x

    MaxTransfer has never been deprecated. In fact, it's only been made superfluous as recent as in AmigaOS 3.2 for internal scsi.device and GVP drivers specifically.

    AmigaOS 3.1.4 FAQ:
    "You need to change this setting for the built-in scsi.device using HDToolBox (select Partition -> Change), to 1FE00. This will limit block transfers to 255 blocks. In the case of third-party drive interface hardware, please consult the corresponding manual to find out the recommended max transfer setting."
    http://aminet.net/docs/help/AmigaOS_3.1.4-FAQ.txt

    AmigaOS 3.2 FAQ:
    "After some back and forth trying to solve this issue, fortunately enough, the HDToolBox "max transfer" value is no longer required on the built-in scsi.device driver of 3.2, and also on drive interfaces made by the manufacturer formerly known as "GVP". In the case of other third-party drive interface hardware, please consult the corresponding manual to determine the recommended max transfer setting."
    http://aminet.net/docs/help/AmigaOS_3.2-FAQ.txt

    > and is ignored by most controllers.

    Actually, it's the duty of the filesystem to implement MaxTransfer functionality, read the respective value from the RDB and act accordingly with data transfers to the device driver. Controllers or their drivers do not know anything about MaxTransfer as they only get in touch with it indirectly, namely by the size of the chunks they receive from the respective filesystem.

    > Lots of talk about data corruption with high values,
    > so probably best to leave it to default anyway.

    Default is too high for ATA-2 and newer drives, so it must be lowered to 0x1FE00.

    Interestingly, it was only in 2011 that Toni Wilen fully discovered the reason for the old issue that makes lowering MaxTransfer necessary:
    http://eab.abime.net/showthread.php?p=759918#post759918
  • »04.01.23 - 20:11
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