[Info-vax] Looking for suggestions for new $GETDVI item codes

[Stephen Hoffman]

On 2015-01-14 19:54:45 +0000, kenneth.randell at verizon.net said:

> Try a DVI$_MAXBLOCK on a drive over 1.0 TB capacity and you get a 
> negative number.  DVI$_FREEBLOCKS has the same issue.

FWIW, whatever programming language you're working with here (DCL?) is 
apparently defaulting to a 32-bit, signed longword, integer 
representation.

sys$getdvi[w] is returning an unsigned longword value, as that's the 
only way to fit a 2 TiB block value via a longword.

The DCL environment just doesn't implement unsigned integer values.  
Nor does DCL offer floating point values, quadword signed or unsigned 
integers, nor extended-precision math, nor arrays and dictionaries and 
data structures, definitely no objects, command line completion, 
immutable data, UTF-8 character encoding, regular expressions, nor 
user-written lexical functions or any other forms of extensions, or 
other increasingly-expected constructs.   And yes, there are some 
hack-arounds available for some of these.  But integers?  Those are 
signed values.

Part of the delay involved in extending the supported volume sizes to 2 
TiB was due to the need to ensure that existing OpenVMS system code 
always treated the disk size values as unsigned integers.  Prior to 
that work, the OpenVMS code had never been supported past 1 TiB, and 
was expected to have some "wrinkles".




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