Re: Ultra10 problems with -current

[Mouse <mouse%Rodents-Montreal.ORG@localhost>]

> For SCSI drives some versions of OBP are limited to READ(6) or
> READ(10) commands.  READ(6) is limited to 16 bit block numbers or
> 33MB bytes.  READ(10) is limited to 32 bit block numbers or about 2T.

I'm fairly sure the 6-byte read operation has 21 bits of block number,
not just 16.  That's certainly what the NetBSD kernel code thinks:

struct scsi_rw_6 {
        u_int8_t opcode;
        u_int8_t addr[3];
#define SRW_TOPADDR     0x1F    /* only 5 bits here */
        u_int8_t length;
        u_int8_t control;
};

This puts the limit at 1G, not 32M, and that's certainly the limit I've
seen in practice.  Other Sun firmware versions have a 2G limit (I
speculate it's keeping byte offsets in signed 32-bit values); yet other
versions seem to have no limit, though I haven't tried anything
terabyte-sized, so they may well have a 2T limit.

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