[geeks] Seagate buckles to math ignorant consumers

[Francois Dion]

On 11/2/07, Shannon Hendrix <shannon at widomaker.com> wrote:
> On Nov 2, 2007, at 10:53 AM, Francois Dion wrote:
>
> > On flash, they already are. Check df -h on a 256MB or 2GB usb stick,
> > you will be unpleasantly surprised. The 2GB usb stick I'm giving away
> > on my blog, with Belenix pre-loaded is showing:
> > /dev/dsk/c5t0d0s0      1.8G   833M   961M    47%    /media/JD FIREFLY
>
> Oh please, think for a moment.
>
> That's due to filesystem overhead.
>
> You should know better.
>
> This is a geeks list after all.

That's why I also listed rmformat's output.  This is raw, without
filesystem overhead. One might expect 5% overhead, but i'm showing
clearly 10% with df of which half is due to the manufacturer calling a
key 2GB but raw space is 1.9GB.

Similarly, my 320GB usb hard disk shows as:
 1. Logical Node: /dev/rdsk/c1t0d0p0
        Physical Node: /pci at 0,0/pci1028,1c1 at 1d,7/storage at 1/disk at 0,0
        Connected Device: MAXTOR S         9QF00FYG D
        Device Type: Removable
        Bus: USB
        Size: 305.2 GB
        Label: <Unknown>
        Access permissions: Medium is not write protected.

And my 4GB flash as:
     2. Logical Node: /dev/rdsk/c5t0d0p0
        Physical Node: /pci at 0,0/pci1028,1c1 at 1d,7/storage at 7/disk at 0,0
        Connected Device: LEXAR    JD FIREFLY       1100
        Device Type: Removable
        Bus: USB
        Size: 3.8 GB
        Label: <None>
        Access permissions: Medium is not write protected.

The loss is even more impressive on my 500.

As far as the size, in rmformat it is calculated based on the struct
smmedium_prop_t, specifically:

int32_t sm_blocksize;	/* Medium block size in bytes */
int32_t sm_capacity;	/* Medium capacity in no. of blocks */

And then displayed in human readable format (/1024 for MB and one more
time for GB). So 320,000,000 ends up as 305GB and 2,000,000 ends up as
1.9GB.

Francois