Re: iSCSI: Decimal encoding - why 64 bits ?

[Martins Krikis <mkrikis@yahoo.com>]

--- "Julian Satran (Actcom)"
<Julian_Satran@actcom.net.il> wrote:
> Martins,
> 
> In fact reading your note I went back and found an
> error we may want to
> correct:
> 
> TargetPortalGroupTag is a 16 bit binary string and
> not an number (there is
> no TPGT that is lower or higher than another TPGT).

Again, I don't have draft 14 in front of me but
13 says that TPGT is "a simple unsigned-integer
between 1 and 65535" (2.4.1 (e)) and a "numerical-
value-from-1-to-65535" (11.9). I would prefer it if
you did not change this to a "binary string" just
to prove a point that there are binary strings
for which decimal encoding is natural. That, IMO,
would be a very profound change at an extremely
late stage. (If you do, I'll make sure all my
TPGTs start with 0x00 and deny all attemts to
encode them in decimal :-)).

> There are no good examples that need decimals other
> than TPGT but I see no

Even TPGT is not a good example, as it is defined
to be a number, for now at least.

> point in disallowing them for vendor keys and future
> extensions. Any
> implementation will have the conversion routines.
> Restricting the use of
> decimals beyond what we did does not strike me as
> useful.

Others (and there are many) here seem to be 
disagreeing with you.

The conversion, while possible, will likely
first use some common library routine, then
byteswap (if running on little-endian), then
do a pass to eliminate leading 0-bytes, which
are not representable in decimal. 

OK, my final argument. Here are two binary
strings, encoded in hex: 0x01 and 0x0001.
Can you give us an example of encoding both
of them in decimal in such a way that they
can be distinguished?

Martins Krikis, Intel Corp.

Disclaimer: these opinions are my own and may
            not be those of my employer.


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