People writing their own A/UX device drivers for a tape backup should be aware of a limitation on the physical I/O buffering between the kernel and the tape cartridge driver.
As an example: a fixed, 8K, physical, I/O buffer was built into the kernel. As a result of this limitation, any calls to "physio" split 64K blocks of data into 8K chunks. Any attempt to pass 64K to "physio" will result in 8 passes of 8K instead of one pass of 64K.
Article Change History:
23 Aug 1994 - Reviewed and updated.
27 Aug 1992 - REVIEWED for technical accuracy.
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