The problem#

So you've built a new computer with fresh blank storage. How do you actually do anything with that computer that has no software? Navigating the BIOS menus can only hold your interest for so long.

The solution#

The old way of doing things was to have a bootable CD or DVD, but now that most computers don't even have an optical drive, the common way to handle this with bootable USB flash drives.

Most Linux distributions' default download is an image for a bootable "live" flash drive (or DVD) that runs the OS in addition to having an option to perform a permanent install. Some of the most popular ones are Debian, Ubuntu, Mint, and Fedora.

You can boot Windows off a flash drive using Hiren's BootCD, which also includes a lot of recovery and diagnostic tools.

While most boot drives will boot into Linux or Windows, there's a small set of specialized lower-level tools. One very useful one is Memtest86+ (included in many Linux distros), which will determine if your RAM is functional. As bad RAM can cause very weird and different to track down problems, you should always test new RAM.

The details#

The problem#

USB flash drives have gotten very cheap, especially if you don't care too much about the speed or capacity. It's convenient to buy multiple for no more than a few dollars each to always have one available or even to just give away. But sometimes very cheap hardware is non-functional or even counterfeit, claiming to be able to store more data than it really can, so when you try to read that data it will be corrupted or missing.

The solution#

f3 ("Fight Flash Fraud") is a tool for testing flash drives (including SSDs). The basic usage is

( f3write '/mnt/usb/' && f3read '/mnt/usb/' ) | tee f3-log

Replacing /mnt/usb/ with the directory your flash drive is mounted at. If you're testing multiple drives, give the log file a descriptive name to identify which drive the test is for.

(Or use the log-f3wr helper script included with f3 which does basically the same thing.)

That will write files to fill the flash drive and then read them back and verify they contain the same data that was written. This both checks for counterfeit drives as well as failing (or dead-on-arrival) drives. In addition to reporting if the drive is in fact capable of storing as much data as it claims, it will report the average write/read speeds while performing those operations, so it doubles as a simple benchmark.

You should always test new drives before trusting them with real data.

The details#