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tableau-parm frequently asked questions

Q. Why is Linux or FreeBSD required?

A. This project is designed to give free operating systems access to Tableau write blocking bridges' HPA and DCO features. A Windows program is provided by Tableau for this purpose, but no Linux/Unix program existed previously. Currently only Linux and FreeBSD are supported, but other free operating systems may be supported in the future either through the use of sg3_utils or through native platform SCSI code. Note that tableau-parm may work ok on other platforms currently supported by sg3_utils, but these simply haven't been tested. Please contact me if you have success on the other operating systems.

Q. How do I detect HPA and DCO sections using tableau-parm?

A. You will want to check the hpa_in_use and dco_in_use flags, in addition to the capacity values.

Q. I have a disk which, according to tableau-parm, contains an HPA section. However, my operating system reports the disk size as if this section isn't hidden. What's going on?

A. Tableau bridges automatically disable HPA sections temporarily, and the operating system is given full access to this area. The HPA section technically still exists, and would hide data in a normal situation (i.e. after a reboot with a normal disk controller, data will be hidden again). DCO sections cannot be removed temporarily. The information tableau-parm provides on HPA size will tell you how big the HPA is when the disk is accessed normally.

Q. Why can't I get HPA/DCO information from my SCSI bridge?

A. SCSI disks do not have HPA or DCO features. At least, this is not in the standards.

Q. Why do I need to update my Tableau bridges' firmwares?

A. Bugs were discovered in Tableau firmwares that prevented them from removing HPA and DCO sections on newer disks. It is strongly recommended that you upgrade in order to gain access to these devices' advertized features.

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