%used incorrect in df -v

The history of computer programming is just full of these silly assumptions about how big numbers need to be.

We hope that 64 bit computing eliminates this for a while - at least in new code. Most likely, rewritrs of old code will be hasty and 32 bit and even 16 bit assumptions will be left in logic if not in actual storage. If so, silly bugs will continue to pop up over the span of years.

32 bits is a 4GB address space. That "address" could be disk blocks, so of course a 1,024 byte block size is a 4 Terabyte drive and larger block sizes would allow larger drives. A 64 bit number is 18.45 Exabytes. That's 1,048,576 times larger than 18.45 Terabytes, so you could address a incredibly large disk with as small a block size as you liked.

Newsgroups: comp.unix.sco.misc
Subject: Re: df -v command..
References: <3B94F148.6EFB1D86@hotmail.com>
<9n2t9m$lqs$1@odin.john-richard.co.uk>
<3B950FC9.82283AA@hotmail.com> 
From: spcecdt@deeptht.armory.com (John DuBois)
Date: 05 Sep 2001 05:14:59 GMT
Message-ID: <3b95b4d3$0$325$8eec23a@newsreader.tycho.net> 

In article <3B950FC9.82283AA@hotmail.com>, gd  <parser99@hotmail.com> wrote:
>
>
>Ian Peattie wrote:
>> 
>> In article <3B94F148.6EFB1D86@hotmail.com>, gd <parser99@hotmail.com> wrote:
>> >df -v
>> 
>> Version of OS?
   ^^^^^^^^^^^^^
>> 
>> >Mount Dir  Filesystem              blocks      used      free   %used
>> >/          /dev/root             16431534   5546794  10884740    34%
>> >/stand     /dev/boot                30720     25084      5636    82%
>> >/DATA      /dev/data01          212266844  85758754 126508090     0%
>> >
>> >Any explanation as to why my "df -v" command would report 0% used for

The problem with %used being calculated incorrectly for large numbers of free
blocks (over 2^32/100, or about 43 million) was fixed in 5.0.6, which one hopes
is later than the still-unstated version you're using.

(Article continues after the break)

        John
-- 
John DuBois  spcecdt@armory.com.  KC6QKZ/AE  http://www.armory.com./~spcecdt/
 

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