Free Software Linux

"These patches allow data integrity information (checksum and more) to be attached to I/Os at the block/filesystem layers and transferred through the entire I/O stack all the way to the physical storage device," began Martin Petersen. He went on to explain, "the integrity metadata can be generated in close proximity to the original data. Capable host adapters, RAID arrays and physical disks can verify the data integrity and abort I/Os in case of a mismatch." He noted that support currently only exists for SCSI disks, but that work is underway to also add support for SATA drives and SCSI tapes, "with a few minor nits due to protocol limitations the proposed SATA format is identical to the SCSI". Explaining how this works, Martin continued:

"As you probably know there is a trend in enterprise computing towards networked storage. This is illustrated by the emergence during the past few years of standards like SRP (SCSI RDMA Protocol), iSCSI (Internet SCSI) and iSER (iSCSI Extensions for RDMA)," began Bart Van Assche, proposing that SCST be merged into the mainline kernel. He suggested that while similar to the STGT project which has been part of the mainline kernel since 2.6.20, "SCST is superior to STGT with respect to features, performance, maturity, stability, and number of existing target drivers. Unfortunately the SCST kernel code lives outside the kernel tree, which makes SCST harder to use than STGT."

SCSI subsystem maintainer, James Bottomley, was not convinced, explaining:

"Yes, I know ... another tree, just what everyone wants," quipped James Bottomley, announcing his new merge candidate (-mc) tree:

"This one has a specific purpose: It's my tree tracking everyone else's git and quilt trees so I get early warning if there are going to be any merge issues. However, it struck me it might be useful to anyone wishing to track what's going upstream more closely."

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Jeff Garzik posted a two patch series introducing an asynchronous event notification infrastructure, "enabling SATA Asynchronous Notification ('AN') for CD/DVD devices that support it." He summarized:

"For devices that support SATA AN (only very recent ones do), this means that HAL and other userspace utilities no longer need to repeatedly poll the CD/DVD device to determine if the user has changed the media."

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