Re: Draft of Binary module

On 14 March 2013 13:38, Florent Georges <> wrote:
> On 14 March 2013 12:39, Adam Retter wrote:
>> e.g. sm:chmod(xs:anyURI("/db/myfile.xml"), "0770")
>   Honestly, the Unix permissions octal representation is not
> representing a number.  I mean no one look at a number here, it just
> happens that the permissions have 3 values, for 3 different "persons",
> so an octal representations of 3 bits looked like a good idea.

Sure I realise that actually it us just a sequence of bits. But I am
concerned about the presentation of this, if I am going to call
something an 'octet' it should look and behave on the surface like an
octal number, of course it can be anything you like behind the scenes.

> And
> actually it was not because it constrained the value space to 3
> different permissions (R, W and X).  I always used the "symbolic" for
> that purpose (e.g. "rw-rw----", which is not more symbolic, just
> another representation), both as a user or to implement it (I don't
> remember where I needed that, but I did once).
>   But that is behind the point I think, the point is that a number has
> no base.  Each single one of its representation has a base (well, in
> position-based representations at least).  The base is then used to
> parse and serialize numbers, but not for the numerical operations in
> memory.

I think I follow, but what I am saying is that if you call something
an 'octet' it implies that it is a number in the Base 8 number system
i.e. an octal number, at least to me anyway. I am talking about the
presentation of that number. Of course I understand that in memory it
is all 1's and 0's.

Are you saying that octet does not mean octal number? If so, what does
octet mean? does it in fact mean byte? if so can we just call it a
byte please.

>   Regards,
> --
> Florent Georges

Adam Retter

eXist Developer
{ United Kingdom }

Received on Thursday, 14 March 2013 13:49:30 UTC