bootable ext. USB SSD for backup

[Ralf Mardorf]

On Thu, 16 Mar 2017 21:11:53 +0100, Martin S. Weber wrote:
>Toshiba is clearly underselling the  disk.

I don't think so, I suspect that some bytes are reserved to compensate
borked memory locations.

  [rocketmouse at archlinux ~]$ sudo smartctl -a /dev/sda | head -9
  smartctl 6.5 2016-05-07 r4318
  [x86_64-linux-4.9.13-rt12-1-rt-persianrug] (local build) Copyright (C)
  2002-16, Bruce Allen, Christian Franke, www.smartmontools.org

  === START OF INFORMATION SECTION ===
  Device Model:     TOSHIBA-TL100
  Serial Number:    Y69B703NKKEU
  LU WWN Device Id: 5 00080d c0061b7c8
  Firmware Version: SBFZ10.3
  User Capacity:    240,057,409,536 bytes [240 GB]

GParted mentions 223.57 GiB * 1024 * 1024 = 234,430,136.32 bytes.
MBR, file system entries might take some space, too. OTOH the complete
capacity shouldn't shrink ;).

Regards,
Ralf