300Gb hard drive formatting to 249Gb - boo.

[Alex Teslik]

Hello,

   I have recently installed a new 300Gb Maxtor hard disk:

[root]/home/alex# dmesg -a | grep ^ad1
ad1: 286188MB <Maxtor 6B300R0> [581463/16/63] at ata0-slave UDMA100

This disk has a single partition on it and is formatted in compatibility mode:

[root]/home/alex# disklabel ad1
# /dev/ad1c:
type: ESDI
disk: ad1s1
label:
flags:
bytes/sector: 512
sectors/track: 63
tracks/cylinder: 255
sectors/cylinder: 16065
cylinders: 36482
sectors/unit: 586099332
rpm: 3600
interleave: 1
trackskew: 0
cylinderskew: 0
headswitch: 0           # milliseconds
track-to-track seek: 0  # milliseconds
drivedata: 0

8 partitions:
#        size   offset    fstype   [fsize bsize bps/cpg]
  c: 586099332        0    unused        0     0        # (Cyl.    0 - 36482*)
  e: 586099332        0    4.2BSD     1024  8192    22  # (Cyl.    0 - 36482*)

now, I understand that a Gigabyte to the Maxtor corporation is 300,000,000,000
bytes. So, I would expect this disk to format to 279Gb based on the following
math:

[alex]/home/alex# bc
bc 1.06
Copyright 1991-1994, 1997, 1998, 2000 Free Software Foundation, Inc.
This is free software with ABSOLUTELY NO WARRANTY.
For details type `warranty'.

(((300000000000 / 1024) /1024) /1024)
279

However, when I mount the drive it is formatted to 271Gb, 8Gb less than what I
expected. This wouldn't be so bad except that the available space on the drive
is only 249Gb. :(
Is this right? I feel like I am missing something. Can someone help me
understand this better? I would love to regain the 30Gb I feel I am missing if
possible.

[root]/home/alex# mount /dev/ad1s1e /1

[root]/home/alex# df -h
Filesystem    Size   Used  Avail Capacity  Mounted on
/dev/da0s1a    97M    62M    27M    70%    /
/dev/da0s1e   7.7G   6.2G   938M    87%    /usr
/dev/ad0s1e    72G    66G   817M    99%    /home
procfs        4.0K   4.0K     0B   100%    /proc
/dev/ad1s1e   271G   1.0K   249G     0%    /1

[root]/home/alex# df
Filesystem  1K-blocks     Used     Avail Capacity  Mounted on
/dev/da0s1a     99183    63614     27635    70%    /
/dev/da0s1e   8084746  6477062    960905    87%    /usr
/dev/ad0s1e  75744027 68847899    836606    99%    /home
procfs              4        4         0   100%    /proc
/dev/ad1s1e 284046628        1 261322897     0%    /1

I formatted this drive using the automatic settings in
/stand/sysinstall->Index->Partitions.

Thanks,
Alex