@connorsoliver said in An Overview of Storage Devices - CompTIA A+ 220-901 220-902 Video Training by Prof. Messer:

What did he mean when he said there's only a limited number or writes on a USB flash drive.

So this is a small mistake on the A+ material. They are making assumptions about the storage media based on the communications protocol. But it's based on very common things. A standard USB flash drive using a flash memory technology that "wears out" as you write to it, but essentially never wears out as you read it.

So the way that a USB stick is "meant to be used" is that you store things on it and read it a lot. You can change it, but it isn't meant for constant writes.

So under "normal" use, USB sticks last a long time. But it you write to it constantly (like when using it as swap) you will cause the memory chip(s) to die quickly.

@scottalanmiller said in Slow SSH Logins on Linux:

Often remote SSH logins on Linux can experience a lengthy delay. This is often caused by the SSH daemon on the server defaulting to attempting a DNS lookup of the SSH client attempting to connect to it. Typically we do not want this behaviour as client systems often cannot be verified in this manner but awaiting a DNS timeout can be rather annoying. Many systems configure this on by default. I see this in the Red Hat family including RHEL, CentOS, etc.

The fix is simple, just explicetly add the line:

UseDNS no

To the /etc/ssh/sshd_config configuration file. The default is “yes” and there should be a comment to this effect as well. After making the change, simply restart the SSH daemon for the change to take effect.

service sshd restart

Originally found in 2012 on my Linux blog here: http://web.archive.org/web/20140822224153/http://www.scottalanmiller.com/linux/2012/09/02/slow-ssh-logins/

Ran into this the other day. Windows to Linux was pretty slow, but Linux to Linux (using our Bind server) was super fast. Turned off DNS and GSSAPI and it was fine from Windows.

For testing I'd go with the manufacture tools, but to exercise the drive and possibly help it help itself.. I'd run a level 4 scan with Spinrite.